tag:blogger.com,1999:blog-84813754584030732252024-03-19T01:28:44.784-07:00Experiencing [L|N]ightA Timeline of Sorts about astro|photography Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.comBlogger296125tag:blogger.com,1999:blog-8481375458403073225.post-68384117102040278262023-09-07T11:18:00.005-07:002023-09-07T11:18:51.833-07:00Maintenance Results<p> Measurements in progress, here are a couple of pictures:</p><p>Mount pointing west, measuring the guiding settings and polar alignment via drift analysis.</p><p><br /></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_tdQi9rw6tKy2Bbq2rzgEA-vrkMJ9-W6QKUa-u1xo6-fFrXDqmOVzorM6y365mmRdyzJLVWWZyq0cx9cDpg8d4yVF2K7nPuo_Vibi_mXex2DTRsCMNenKNtvOafo0vq9bEb-heBC44qqkcNxtjh2Uzfpl7rWrn2GGZ--lWuP_9HZXUZqLHfiZAdTlOwM/s2048/53169959671_117c5f3c82_k.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="2048" data-original-width="1536" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj_tdQi9rw6tKy2Bbq2rzgEA-vrkMJ9-W6QKUa-u1xo6-fFrXDqmOVzorM6y365mmRdyzJLVWWZyq0cx9cDpg8d4yVF2K7nPuo_Vibi_mXex2DTRsCMNenKNtvOafo0vq9bEb-heBC44qqkcNxtjh2Uzfpl7rWrn2GGZ--lWuP_9HZXUZqLHfiZAdTlOwM/w480-h640/53169959671_117c5f3c82_k.jpg" width="480" /></a></div><br /><p>Here is the screenshot of the PHD2 Guiding Assistant window from that evaluation:</p><p><br /></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjc70SV0ttAR4DlYu5yIgALlzTaT93hZF4a5ait7vwB1SDnOeckM240J0k-Jz2UAeuCdDlTsyu-SH919d7xEiOtF1HXm6lziPqmxuQ5F_LXPgRskYRy1XlTUtYzP0n-ZWk0mwS34GUP0vzafYpw1fEDe7bnxPHF6y-Qo9cRJLxBP7VmctAEuf8_3aqMLGo/s1600/image%20(1).png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="900" data-original-width="1600" height="360" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjc70SV0ttAR4DlYu5yIgALlzTaT93hZF4a5ait7vwB1SDnOeckM240J0k-Jz2UAeuCdDlTsyu-SH919d7xEiOtF1HXm6lziPqmxuQ5F_LXPgRskYRy1XlTUtYzP0n-ZWk0mwS34GUP0vzafYpw1fEDe7bnxPHF6y-Qo9cRJLxBP7VmctAEuf8_3aqMLGo/w640-h360/image%20(1).png" width="640" /></a></div><br /><p><br /></p><p><br /></p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-84047212417422408332023-09-02T12:09:00.021-07:002023-09-07T11:14:59.571-07:00 Main Axis Bearings on the Losmandy G11 and GM8<p><br /></p><h2 style="text-align: left;">Why update the bearings?</h2><p>As I have found, the Losmandy mounts tend to have a strange behavior when performing a meridian flip. I've long noticed that when polar aligning on one side of the meridian, that a flip to the other side can show an error. This has usually been market up to "cone error."</p><p>Cone error is where the RA and or DEC do not follow a rotation axis that is in alignment with their respective dimension. When they spin around their axis, they show a wobble - or cone - when pointing to a part of the sky. This is usually apparent with Goto slews. </p><p>What's not readily apparent is that the RA cone error will impact polar alignment. If the alignment is dialed in to a precise amount on one side of the meridian, it will show a difference on the other side. I've seen this in logs from PHD2 as well as on the hand contoller. During GSSP, the error reported on the G11 mounts ranged from 7 to 22 arc minuntes.</p><p>In practice, this can be adjusted out by taking half of the error on each side. Thus the error is introduced on one side, leaving less error on the other side. Using the Polemaster, this could be done by swinging the RA through the CWD position during the rotation phase. That way the error is measured on both sides of the mount.</p><div class="separator" style="clear: both; text-align: center;"><br /></div><p></p><p>I got into talking with Michael Herman about the situation because of the heavy weight requirements of the 1200 project. His analysis of the alignment issue is that the cone error is also made worse by the choice of axis bearings i the Losmandy mounts. Because the bearings are made from pin bearings and not self-centering cone bearings, there can be slop or sag in the axis as it spins. Additionally, because the pins are loose, they can move relative to each other, possibly binding or going non-parallel which can add other issues.</p><p>One solution for this is to replace these pin bearings with cage bearings or to replace the pin bearings with a somewhat higher quality unit. Losmandy installs a bearing that is 3/4 long. These are smaller than the max size available (1 1/2 inch long). Several users have replaced them with the longer version to help with the load and improved handling.</p><p>With this in mind, I started working on one of the G11 for the bearing upgrades. Was able to pull the DEC bearings and install the new ones rather easily once I figured out the best method. However, I was unable to pull off the DEC ring gear. Somehow it had become stuck on the shaft. So, I ordered a gear puller - as the one that I had is not large enough to do the job. Should arrive after Labor Day.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjj9gGJb4oyUcIrE6nog1q90ssb-dfamxpcgIRf6uE-kcjUvD-xo3J9lBPGVuRY7PFmlI_SCOT7pCnKo5_FKbl6i2-Nz5DITTwUPlqD-wIE2fQvj5pnVRZVqsWtL-kzzh-OG8IIGHiq1WTmSpoYgkS0F2Koo346cwFBeO1EdteWhQMDIOfTIpFAAsHtAT4" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="3000" data-original-width="4000" height="300" src="https://blogger.googleusercontent.com/img/a/AVvXsEjj9gGJb4oyUcIrE6nog1q90ssb-dfamxpcgIRf6uE-kcjUvD-xo3J9lBPGVuRY7PFmlI_SCOT7pCnKo5_FKbl6i2-Nz5DITTwUPlqD-wIE2fQvj5pnVRZVqsWtL-kzzh-OG8IIGHiq1WTmSpoYgkS0F2Koo346cwFBeO1EdteWhQMDIOfTIpFAAsHtAT4=w400-h300" width="400" /></a></div><div><br /></div><div>The next day I was able to pull the ring gear off with some effort using a bearing splitter/puller and some other tools. However, the center bearing remained stuck on the shaft! So I had to pull that as a separate item.<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgVBpS94QXMX51PjJZYXyxePvNqAQMPNWiTLJ9e9HXPGz91XMjQiNgUoLlEECBbbayzCEYoDnjMebNuSy43on7-uJzcCvcysDR-ywqv2m-7WB0GuwC2aUT80F5wlhLCap9s0FVAKaThbk7xhUIA_A7g8c0cgVpU1gXhW_eq9lPUAIaSbzFCMg-PQy00XG4" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="4000" data-original-width="3000" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEgVBpS94QXMX51PjJZYXyxePvNqAQMPNWiTLJ9e9HXPGz91XMjQiNgUoLlEECBbbayzCEYoDnjMebNuSy43on7-uJzcCvcysDR-ywqv2m-7WB0GuwC2aUT80F5wlhLCap9s0FVAKaThbk7xhUIA_A7g8c0cgVpU1gXhW_eq9lPUAIaSbzFCMg-PQy00XG4=w300-h400" width="300" /></a></div><br /></div><div><br /></div>I expect the replacement thrust bearings to arrive on Friday or possibly next Tuesday. In the meantime, I have an older set that I may be able to use for comparison purposes. <p></p><p>The big worry about the thrust bearings is that because I've used the strap wrench to tighten the axes, I may have damaged these bearings. From what I can see on the wear pattern, there is no evidence of issues with these bearings. The races are polished nicely with no pitting or bad wear patterns. No need to replace the one that I have inspected so far.<br /></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEi4zmJMYivBq8sfnIAJ0fd30YOxemHUlurX-9bmBcjMIeLR7pjH_Pc1EU_A1w5DOUdxg-MKOA31-hiv6KN4Jsb0vRJB_Uo3xz2bAukNADBHLwr0gMwFtlHmCNV0J4NKg2CR06f5x3YBzs733G2V7kCeDPPxGMTerGrqb2XvWgEa4RtOupjsDetdGOc8Qxs" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="4000" data-original-width="3000" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEi4zmJMYivBq8sfnIAJ0fd30YOxemHUlurX-9bmBcjMIeLR7pjH_Pc1EU_A1w5DOUdxg-MKOA31-hiv6KN4Jsb0vRJB_Uo3xz2bAukNADBHLwr0gMwFtlHmCNV0J4NKg2CR06f5x3YBzs733G2V7kCeDPPxGMTerGrqb2XvWgEa4RtOupjsDetdGOc8Qxs=w300-h400" width="300" /></a><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjaetYyNXvg6zX9SstekM-5QmGFbKzBUWQ9LoTi20d5yMxPMczuOV_kVaV8HMVNe933kCOdtej0dZTTglX9aUaMmwVvjtn9gDbHChs4AoXEG3_1mz8BxnmFfFtv-a6Q81hxDckHFASrZKhtDcJahbNPztMzi6hwBaJlLYDttzYvwI9RSFUqxHRCWNwQZQM" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="4000" data-original-width="3000" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEjaetYyNXvg6zX9SstekM-5QmGFbKzBUWQ9LoTi20d5yMxPMczuOV_kVaV8HMVNe933kCOdtej0dZTTglX9aUaMmwVvjtn9gDbHChs4AoXEG3_1mz8BxnmFfFtv-a6Q81hxDckHFASrZKhtDcJahbNPztMzi6hwBaJlLYDttzYvwI9RSFUqxHRCWNwQZQM=w300-h400" width="300" /></a></div></div><p><br /></p><p>To avoid future damage, I will be using Michael Herman's increased friction pads. These will help with locking up the axes so that I don't need to use the strap wrench.</p>There was a large issue when replacing the DEC shaft bearings. Once I'd pressed in the new ones, the DEC bar did not drop down through it. I chalked this up to a learning experience and pressed onwards. Grabbing a bigger hammer (the 11 lbs counterweight), I pressed the it all the way down.<p></p><p>Well, that was a mistake. The rotation was marred by a repeating tight spot, almost as if the rollers were passing over a flat area. I figured that either the bearing was damaged or I'd manage to damage the bar.</p><p>I brought the DEC axis to Michael on Tuesday after work, we discussed it, and collaborated on some possible replacement parts. That evening when I got back home, I wailed on the axis to get it back out. Yes, the damage was obvious and clear.</p><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="361" src="https://www.youtube.com/embed/YFXDs8ov9Ow" width="434" youtube-src-id="YFXDs8ov9Ow"></iframe></div><br /><p><br /></p><p>See this video showing how the offending bearing catches on that part of the shaft. The best I can figure is that it may have been cocked during installation and caused binding. </p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjbdOw4xyBj3C5LjUTgknurDHmp2S6SAUq1U6PeOg3JBld9G2UREFcZ0PlUtcDY8Q_KK3FmWOuZRvrzK0EPDnZfe9cQGYrbTHhinUgqhjB3HfLxB9p6wjTeJ5L8DgYJckbLnKd1f7U0uiRifX9Ogc-oDoYUDnYj7D8EeyS1ekZ4eCrXTtiG6vqz-uglPxM" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="4000" data-original-width="3000" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEjbdOw4xyBj3C5LjUTgknurDHmp2S6SAUq1U6PeOg3JBld9G2UREFcZ0PlUtcDY8Q_KK3FmWOuZRvrzK0EPDnZfe9cQGYrbTHhinUgqhjB3HfLxB9p6wjTeJ5L8DgYJckbLnKd1f7U0uiRifX9Ogc-oDoYUDnYj7D8EeyS1ekZ4eCrXTtiG6vqz-uglPxM=w300-h400" width="300" /></a></div><br /><br /><p></p><p>To fix these grooves in the stainless metal, I used some emery paper in in the painting supplies. I rolled the bar in the paper by hand and repeatedly inspected so that the amount of material removed was not too much. This made it possible to polish out the smallest of the damaged areas. Only the deepest cuts remained. Of course, I am concerned that this may introduce a bigger error on this DEC as the lower end could have the freedom to wobble. I may install a wider bearing at this place to mitigate the problem. Also, I could note that this mount should not carry the heaviest payloads.</p><p>I put back the standard pin bearings and found that the DEC shaft now dropped into place easily.</p><p><br /><br /><br /></p><p>Next steps: </p><p><br /></p><p>Repeat for the RA axis and for the second G11.</p><p>The parts from Misumi are expected to arrive today.</p><p><br /></p><p>Also to be done: RA4 bearing upgrades for the worms with specific belleville washers for these bearings. This should reduce the backlash as measured by PHD2.</p><p><br /></p><p>Also to be done: Assembly of belleville stacks to implement a "spring loaded" worm for the DEC on the three mounts. This should also reduce the backlash as measured by PHD2.</p><p><br /></p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-66282722670826614852023-09-01T13:31:00.001-07:002023-09-01T13:31:00.155-07:001200mm Project: Custom Bellows<h2 style="text-align: left;">Bellows Installed </h2><p>As can be sees from the pictures, the 1200mm project has the custom bellows installed.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEh3BJvymaR072aFp1Lwnsb8F61Y0piANkBQpHyQVC8bCOCYqLwNCf-V8VGeVrLV4shOGdRboDf6jTAzpHtuVN7nGeZ_BCad-afZhYc5oSCw2LFpa6OX2z1t3y8053K6wvWaUBrxZK4ToHS5G9FdBnU0cc8puTAO1_oKtNETazqmqCY3KTfKI-_R09ar8dI" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="4000" data-original-width="3000" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEh3BJvymaR072aFp1Lwnsb8F61Y0piANkBQpHyQVC8bCOCYqLwNCf-V8VGeVrLV4shOGdRboDf6jTAzpHtuVN7nGeZ_BCad-afZhYc5oSCw2LFpa6OX2z1t3y8053K6wvWaUBrxZK4ToHS5G9FdBnU0cc8puTAO1_oKtNETazqmqCY3KTfKI-_R09ar8dI=w300-h400" width="300" /></a></div><br /><br /><p></p><p>I'm glad that I waited. I'd received the bellows in mid-August. I was not fully ready to install as I had not received the material for the front standard and installing the rear standard early would be too limiting. So I was patient and considered the process I would take.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjWXY_i6dMIKjNwKkMEkQibjyZFV95EPXSyNArq3Uyt-2GpvZ65loVQN2-c3pIydZtIY1stXdjM4mzyoGiN_J9qrttjO39qTuZKAssDRX4MlItBVIfJR-p6UnzhhVu_s62GBDpOAj7fYixm3A5LAtzSZIutS2TcQUICbBe6Pk3fWEpx9PhjeisBtvfWPL8" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/a/AVvXsEjWXY_i6dMIKjNwKkMEkQibjyZFV95EPXSyNArq3Uyt-2GpvZ65loVQN2-c3pIydZtIY1stXdjM4mzyoGiN_J9qrttjO39qTuZKAssDRX4MlItBVIfJR-p6UnzhhVu_s62GBDpOAj7fYixm3A5LAtzSZIutS2TcQUICbBe6Pk3fWEpx9PhjeisBtvfWPL8=w240-h320" width="240" /><br /></a></div>On Saturday, I was thinking about the measurements required to use the compass attachment on the dremel tool. Was walking to get some burrito for supper and it was a good opportunity to think about the dimensions and what would be required to make the hole. The box of the attachment was a bit misleading - it suggested that the device could only carve a circle up to 7 inches in diameter. I mis-read this and it is actually 7 inch radius. Still, the thoughts helped me prepare for the task.<p></p><p>No pictures of the actual cutting process. My work area is the floor of the shed - no table, no vise, no clamp - just what I can handhold and manipulate. Cutting the delrin was interesting. The routing bit was able to push through the plastic and there were times when it was going smoothly. Then other times when I had to back off. For whatever reason, I did not clamp down the radius as tightly as it should have been and the circle got a little bit too large. You can see where the ends did not meet up:</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEirUq_msZB95tEDh7kmYjkbF-efzMV__-CEzYHTM0BALE3pptwSlJm4tyh2PKngkoVH2hrzqbTOJ5-3aP6dIZKdcjg3ltu_RP7EJbWe7Z1TaLT2zMmQ2q2P5EpajIQVuKXsUUxNkc99Oi85G-m8kb6t-fSvzf608Rt-p5sxqEumXqM4lzaAbbxkMDNwCDw" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/a/AVvXsEirUq_msZB95tEDh7kmYjkbF-efzMV__-CEzYHTM0BALE3pptwSlJm4tyh2PKngkoVH2hrzqbTOJ5-3aP6dIZKdcjg3ltu_RP7EJbWe7Z1TaLT2zMmQ2q2P5EpajIQVuKXsUUxNkc99Oi85G-m8kb6t-fSvzf608Rt-p5sxqEumXqM4lzaAbbxkMDNwCDw=w240-h320" width="240" /></a></div><p></p><p>The edges were furry and ragged. I went over the whole thing with a sandpaper block to round them to prevent sharp bits from biting me in the dark. The brushed look is very attractive.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEhE6fNWWwf6CLHS3Zw9lIzG62gTm6YbFKvosKjoJV4JQPSPbdZGSO9j0K0vEepLgdkTLmWR00qf8DCCC37Gh5KpxQlF5hj8mlktjOOmgjGB3AqZDzjJDtQ4IMujIY9PUX44-3xBdpZ9qFpY-c9rlUOgMosAqV6b9I-xsYdUdnZACx5XgpeQXquiQ3VAxpk" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="4000" data-original-width="3000" height="240" src="https://blogger.googleusercontent.com/img/a/AVvXsEhE6fNWWwf6CLHS3Zw9lIzG62gTm6YbFKvosKjoJV4JQPSPbdZGSO9j0K0vEepLgdkTLmWR00qf8DCCC37Gh5KpxQlF5hj8mlktjOOmgjGB3AqZDzjJDtQ4IMujIY9PUX44-3xBdpZ9qFpY-c9rlUOgMosAqV6b9I-xsYdUdnZACx5XgpeQXquiQ3VAxpk" width="180" /></a></div>Putting the bellows on this frame was pretty easy. I just cut down the end of the bellows - the maker ETone had left extra fabric for me to use. (I have quite a bit of fabric now for patching.) Glued this large end to the delrin frame with some strong silicon glue. Let it cure overnight with a weight providing pressure on it.<p></p><p>Putting the Toyo frame on the small end was muc<br />h easier than in the past. I've learned a lot about how to handle this task over the last few projects. I've learned to trim extra fabric away from the corners and clear the screw holes. A tiny bit of superglue works well to stick the bellows onto the metal frame before screwing it down. Super easy and it was done in less than an hour total.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEhuzREVLUrc3bPBHNA1_F7ZKdw6TFNL6UO0MQVSJOtTazjN_MGp8WlGA-Vn4SfLwtGz1DH8epvZU8PYi6jmhs40r8wj6gDYwMWT4fYCYBRH1ZtcI4pCM1qR_G-n1BRIgJs5aCorQJyPZ3yWYTq42e81s9sMXOLBJKv-iUbAcbd95nWoa1-EPhejOM27BjM" style="margin-left: 1em; margin-right: 1em;"></a><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEhuzREVLUrc3bPBHNA1_F7ZKdw6TFNL6UO0MQVSJOtTazjN_MGp8WlGA-Vn4SfLwtGz1DH8epvZU8PYi6jmhs40r8wj6gDYwMWT4fYCYBRH1ZtcI4pCM1qR_G-n1BRIgJs5aCorQJyPZ3yWYTq42e81s9sMXOLBJKv-iUbAcbd95nWoa1-EPhejOM27BjM" style="margin-left: 1em; margin-right: 1em;"></a><a href="https://blogger.googleusercontent.com/img/a/AVvXsEigeQvRbIuc7-ZPYPVIEifI_PvZLDNLfnPp3sdGTFl_7GnHopTIPfO56eRos3cdlFV2R8Z0ySeRKn0HHAEjGomUFy9n1-9m2kdasCb75H--R-6lrEyp5NYQzHdVKSDLkTURnmDYqJEB4U-hrj8FMdYrwPMo9QmLebyKNHODvp8GOTJ0qoSG02XF3JGju5I" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="4000" data-original-width="3000" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEigeQvRbIuc7-ZPYPVIEifI_PvZLDNLfnPp3sdGTFl_7GnHopTIPfO56eRos3cdlFV2R8Z0ySeRKn0HHAEjGomUFy9n1-9m2kdasCb75H--R-6lrEyp5NYQzHdVKSDLkTURnmDYqJEB4U-hrj8FMdYrwPMo9QmLebyKNHODvp8GOTJ0qoSG02XF3JGju5I=w300-h400" width="300" /></a></div><br /></div><p></p><p>The bellows looked great - the 9 inch square delrin frame is ideal size.</p><p>The front standard fit snugly over the back of the lens. I put a strip of flocking material around the lens so that there was no light leakage. In thinking, I may need to put a bit more flocking on one more surface just to make sure that there are no additional leaks. Given the use of this at night I doubt there will be any issues - the path of light around these areas requires a single right angle reflection, so I'm not sure how much could get in. Direct light shining on the scope body at the flange would be enough - will have to check with a bright light.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEhGS-FeAnNjOnl9WvXKj91Qosyf4HRtCKYR-uThqzibvzyFeY8PzgIFdRjzZN3r5Uzz794EVfo1-FU7rMvcbgHx20CWxaNeMgvxKEPR4kR7r4uZ-3GE6Wji8Ey8SvjSNTlO7ehQI-a26MIhZCy-0y1Z7zkEqZwtx_Q8GDgSMOcFduVhxK8-xgGE9rTq6B0" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="4000" data-original-width="3000" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEhGS-FeAnNjOnl9WvXKj91Qosyf4HRtCKYR-uThqzibvzyFeY8PzgIFdRjzZN3r5Uzz794EVfo1-FU7rMvcbgHx20CWxaNeMgvxKEPR4kR7r4uZ-3GE6Wji8Ey8SvjSNTlO7ehQI-a26MIhZCy-0y1Z7zkEqZwtx_Q8GDgSMOcFduVhxK8-xgGE9rTq6B0=w300-h400" width="300" /></a></div><br /><p></p><p><br /></p><p><br /></p><p>Stretchy bellows.</p><p><br /></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEgebbyoeisWeoFeuqt__Q2CY6OQz91pS8pVQiGC-yt18xlSxt0mcAJ0jZxPVjm7wTO__4bIizFHOnHDtvhFnJMiNy5snwu8dQXkz-FJSYgwdrf5sUmE-HK6VPi4fEFW4XYwxspr2FOfrtDCjGS8lH0vvwHRhj5i6JKR2hZEp1B1i3SiTUoIjktNsL1EGPo" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="4000" data-original-width="3000" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEgebbyoeisWeoFeuqt__Q2CY6OQz91pS8pVQiGC-yt18xlSxt0mcAJ0jZxPVjm7wTO__4bIizFHOnHDtvhFnJMiNy5snwu8dQXkz-FJSYgwdrf5sUmE-HK6VPi4fEFW4XYwxspr2FOfrtDCjGS8lH0vvwHRhj5i6JKR2hZEp1B1i3SiTUoIjktNsL1EGPo=w300-h400" width="300" /></a></div><br /><p></p><p>The front standard is glued to the bottom half of the rings. The top surface has no adhesive and this is the spot that might need some felting. When I put the scope horizontal again I will check.</p><p><br /></p><p>Next steps:</p><p><br /></p><p>Make the dew shield from the aluminum plate. Not sure if I am going to pop rivet it together or use adhesive. The pop rivet seems fast and secure - however it will put the ugly bit of the rivet on the outside of the shield - the smooth part of the rivet must be on the inside so that it does not protrude into the light path. This is where an adhesive would be preferable - no protrusion into the light path to cause diffraction spikes.</p><p><br /></p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-56259009805249415942023-08-31T10:17:00.004-07:002023-09-01T08:55:34.483-07:001200mm project: guide scope<p> </p><h2 style="text-align: left;">August 14 I did the following:</h2><p><br /></p><p>Unwrapped the guide scope from Astromania. </p><p>Early thoughts:</p><p></p><ul style="text-align: left;"><li>Small overall size for a 400mm guide scope. Not much smaller than a strippled down ST80. Given the small space inside the square tube, there was not enough room for the larger device.</li><li>Uncoated optics. Not happy about this. Will see how it performs. It's mostly about controlling flare and keeping the stars from being too bloated.</li><li>The focuser has a thumbscrew that locks it down. Will have to look at the rest of the body to ensure that I'm not missing grub screws.</li><li>The ring thumbscrews were not the best. Two were missing the nylon inserts. Glad that I won't be using them.</li></ul><p></p><p><br /></p><p>Did a trial fit of the guide scope inside the 6x4 box. The scope fits but not the rings. This was expected and I had ordered an extra finder foot holder to go with this project.</p><p><br /></p><p>Removed the rings, marked the position of two holes on the body of the scope, drilled holes for the M5 screws, and then mounted the Synta foot dovetail on the scope body. To access the inside of the scope, I needed to unscrew both the lens and the focuser. This allowed my fingers to hold the nut that went inside the body. These will stick out into the possible light path. Not much that I can do.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEj30R1cJGYDKaf_Bw8h4bFZIdNx4KkRPRGftLtdvv8-oVd3tzv1iid22uEICMZjIjsaRnQTgk5d6d7sdMChzVtI-0t4heuR5BIU1bnxMJdPlg0FAghQBx9r0vJ22lsIx0TGzYARKcwxKycPwrVTQrowQNABSxi2AikPnGHvjNroXB-gr03Qfcxri4iMA78" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="4000" data-original-width="3000" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEj30R1cJGYDKaf_Bw8h4bFZIdNx4KkRPRGftLtdvv8-oVd3tzv1iid22uEICMZjIjsaRnQTgk5d6d7sdMChzVtI-0t4heuR5BIU1bnxMJdPlg0FAghQBx9r0vJ22lsIx0TGzYARKcwxKycPwrVTQrowQNABSxi2AikPnGHvjNroXB-gr03Qfcxri4iMA78=w300-h400" width="300" /></a></div><br /><br /><p></p><p>Then, I marked the place where I could run two screws though the bottom of the box. This needed to be drilled. Did it freehand with the dovetail bar as a guide. Was patient and the drill went well.</p><p><br /></p><p>Then, I assembled the mounting bar and tightened it down with M6 bolts with a jam screw. Looks good.</p><div class="separator" style="clear: both; text-align: center;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjcH_gBvJn1a1E62ZLGfAX3Aj9ihgwbj_KaefktTmbPfT5lOxElj0aen8-zhoiaf0aY37thuf2ujlmWjWBYpvEH0Q5Ux21w-uGKoVv1nvGB2ajPaSZUrcxVaHIP3TGYrcO4cQo9ENZ8waKXiR7dBPxKuZFK5M1eo40n4XG4rx_4ly5-Tu9K7tu1cB743v8" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="4000" data-original-width="3000" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEjcH_gBvJn1a1E62ZLGfAX3Aj9ihgwbj_KaefktTmbPfT5lOxElj0aen8-zhoiaf0aY37thuf2ujlmWjWBYpvEH0Q5Ux21w-uGKoVv1nvGB2ajPaSZUrcxVaHIP3TGYrcO4cQo9ENZ8waKXiR7dBPxKuZFK5M1eo40n4XG4rx_4ly5-Tu9K7tu1cB743v8=w300-h400" width="300" /></a></div><br /></div><p></p><p><br /></p><p>Unfortunately, my hand was not large enough to fit into the square tube and manuipulate the thumb screws. I borrowed Abby to see if her hand was small enough. She was not able to do it either. The option now is to put the scope on the dovetail bar outside of the box, then assemble it.</p><p>To do this required attaching the bar with the nuts glued in place and run the screws up from the bottom. This was done the next day as I had run out of time on the first effort.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEg6HhAisbMSjwcznhSAfhY9Zg0Iukr-zGS7XoKkgIKsK1xkz09Oh_HRGbYLXRuzYC7W5gybWb_2MBs-9HyzkYxaPWDwq6BSPbnVwKPqYYOe1Ispu5GvQNU5ytsiOIzZOsKNYWFqqP96u0zVmA2MLREVd2F37x7sYRcZyU4xeFvoWyAKFWmjetj7tHjikB4" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="8000" data-original-width="6000" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEg6HhAisbMSjwcznhSAfhY9Zg0Iukr-zGS7XoKkgIKsK1xkz09Oh_HRGbYLXRuzYC7W5gybWb_2MBs-9HyzkYxaPWDwq6BSPbnVwKPqYYOe1Ispu5GvQNU5ytsiOIzZOsKNYWFqqP96u0zVmA2MLREVd2F37x7sYRcZyU4xeFvoWyAKFWmjetj7tHjikB4=w300-h400" width="300" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/a/AVvXsEjdifCOuuHEqGhYbd_qKnwV1Q2hVh0P59z7khN-Dpw_1XnSpzvbbaNPYy8eo8T--EdPJQF2tUQrE9F1OLghYr1PSjnyG5ViqnScufJ6rJZzKwfCPrFHzMqR1yhEmys3yI9dJumgPJmUth6NSjGv7kdBCAeUWfUGDI3GeAIlDg5KHzAVloPibJvKI_5_qu4" style="margin-left: 1em; margin-right: 1em;"><img alt="" data-original-height="8000" data-original-width="6000" height="400" src="https://blogger.googleusercontent.com/img/a/AVvXsEjdifCOuuHEqGhYbd_qKnwV1Q2hVh0P59z7khN-Dpw_1XnSpzvbbaNPYy8eo8T--EdPJQF2tUQrE9F1OLghYr1PSjnyG5ViqnScufJ6rJZzKwfCPrFHzMqR1yhEmys3yI9dJumgPJmUth6NSjGv7kdBCAeUWfUGDI3GeAIlDg5KHzAVloPibJvKI_5_qu4=w300-h400" width="300" /></a></div><br /><br /><p></p><p>See the above pictures on how it looks installed. Pretty snazzy!</p><p>Eventually I put a red dot finder on the top of the main scope and it would be nice to put an RACI finder on it as well for precise centering.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhgdMFTaaf6sxVgcZ48QP9iVNAhKm0F0P5_5eurc2qbyAj4nc_KwuRAksuEsdbdsOYaeYQ_q7kSXrpQPDYli4fWBUgBNxRvwgjbYas6ESNxFkRn69H4fpAQ6pl6wNAn0R5siSXqKuIRyyiIcURKLBefW0dSGaVdumYpm-Fzrz9HD123SmU6CO1zTejTqyo/s8000/red-dot-finder_53119636581_o.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="8000" data-original-width="6000" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhgdMFTaaf6sxVgcZ48QP9iVNAhKm0F0P5_5eurc2qbyAj4nc_KwuRAksuEsdbdsOYaeYQ_q7kSXrpQPDYli4fWBUgBNxRvwgjbYas6ESNxFkRn69H4fpAQ6pl6wNAn0R5siSXqKuIRyyiIcURKLBefW0dSGaVdumYpm-Fzrz9HD123SmU6CO1zTejTqyo/w300-h400/red-dot-finder_53119636581_o.jpg" width="300" /></a></div><br /><p><br /></p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0North Fair Oaks, CA, USA37.474382299999988 -122.19663199.1641484638211423 -157.3528819 65.78461613617884 -87.0403819tag:blogger.com,1999:blog-8481375458403073225.post-90258142270719800242023-08-15T13:44:00.000-07:002023-08-15T13:44:02.104-07:00Setbacks and Recovery<p> During the second week of August, I experienced some setback on the 1200 project and was able to recover.</p><p><br /></p><p>Early in the week, I had the chance to perform the test to find the infinity focus point for the lens. It was a convenient 30 inches past the flange. How nice!</p><p><br /></p><p>Unfortunately, when I reached out to Parallax for the quote on a custom aluminum tube, Joe advised that they would not be able to meet the design requirements. Bummer. Back to thinking about alternate ways to provide a light-tight back to the lens.</p><p><br /></p><p>When I was taking the setup down the following day, I found a few things that were less than pleasing. </p><p><br /></p><p>First, I saw that the position of the rear standard was significantly off from where I'd expected it to be. Turns out that it had drooped due to a loose screw. Easy enough to fix once I found an insert to bring the 3/8-16 thread socket to another 1/4-20 thread. With two mounting screws, it's unlikely that it will move in the future.</p><p><br /></p><p>Second, I saw that the rotating film back that I'd picked up on ebay was not very tight. The film holding elements were loose and allowed rotation or movement with just a finger touch. As this was part of the early Toyo design, there didn't seem to be a way to lock down the rotation. Luckily, by the time I searched on ebay again, I was able to find a more modern back both domestically and in JP. Ordered them both and between the three I should be able to cobble together a precision back with ground glass.</p><p><br /></p><p>At this same time, I decided to reach out to Michael Herman for his network to find a Losmandy Titan. This started a long email exchange, talking about the methods to improve the Losmandy mount design. Suffice to say, the Titan is a great mount, but it suffers from being based on the lesser choices from the family. Specifically, the choice of pin bearing instead of a centering bearing can give the RA axis a chance to flop when the meridian is flipped.</p><p><br /></p><p>The amount of movement is low, yet enough to show up in pointing model from one side to another. This is probably the source of the polar alignment error from east to west.</p><p><br /></p><p>One way to eliminate this flop error is to check the polar alignment WITH the flop in mind - understand the cone error and measure the polar alignment on both sides of the meridian. Split the difference and accept the error on both sides.</p><p><br /></p><p>Another way would be to replace the bearings. </p><p><br /></p><p>Michael shared a document that he'd been making that covers much of the methods that can be used to improve the mount. I ahve done many of these steps - including the McLennan gear boxes and some of the RA4 bearings. I had found less than optimal use of the belleville washers - mostly because I had installed incorrect ones incorrectly. I also may have installed the thick and thin thrust bearing races in the wrong order.</p><p><br /></p><p>With some back and forth, additional research and shopping, I have ordered the following parts:</p><p><br /></p><p>From McMaster:</p><p>RA4 belleville washers</p><p>RA4 high precision bearings</p><p>Caged versions of the RA and DEC shaft pin bearings, longer than standard.</p><p><br /></p><p>From Amazon:</p><p>Bearing puller and press</p><p><br /></p><p>Also from Amazon but unreleated to the rebuild - the guide scope that will go inside the rectangular tube.</p><p><br /></p><p>From Misumi:</p><p>Thrust bearings with races - it's likely that by using the strap wrench to tighten the clutches that I've damaged the thrust bearings. </p><p><br /></p><p>From Michael: </p><p>His high friction clutch pads so that I don't have to use the strap wrench.</p><p><br /></p><p>From Newark (aka Fastenal):</p><p>4 more McLennan gear boxes to upgrade the G11 and to have a spare.</p><p><br /></p><p>The parts will slowly drift in over the coming weeks. When Michael is back in town at the end of the month I may have the chance to rebuild one of the G11 with the newer parts.</p><p><br /></p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-17061608105672821942023-08-11T15:17:00.002-07:002023-08-11T15:18:02.548-07:00Progress on the 1200<h3 style="text-align: left;">The big project lens has moved forward significantly in the past week.</h3><p><br /></p><p>I received the rings last week and after mounting the lens into them, it was plain that the lens needs to be raised higher to meet the center point of the rear standard.</p><p><br /></p><p>I ordered a 6 inch by 4 inch aluminum rectangular tube that is 12 inches long. Learning from the 900 project, I did not expect to cut the tube and left it as a single item. Thus, no mis-alignment would happen from front to back. Online Metals was able to provide the cut tube and have it in my hands by Thursday. Thus, the heat was on...</p><p><br /></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrr1rCGV_h-Z4D6dxGXP2gu5N4TI2kRga4pvky5iSWFwOBGSvWGTqgsiN2o_FBxUehhYOADsFh4k1aptYLpfPH4FntUh2RnQdo7wi3zzBTUDQElUmBD3oY_-nv4EfFTkXK6uNtDaorjPxsnuDUD9VgyWJGNlM4_iOQxPl33ijO4_8S7vYXogdFFvLMeEY/s4000/IMG_20230807_205359.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjrr1rCGV_h-Z4D6dxGXP2gu5N4TI2kRga4pvky5iSWFwOBGSvWGTqgsiN2o_FBxUehhYOADsFh4k1aptYLpfPH4FntUh2RnQdo7wi3zzBTUDQElUmBD3oY_-nv4EfFTkXK6uNtDaorjPxsnuDUD9VgyWJGNlM4_iOQxPl33ijO4_8S7vYXogdFFvLMeEY/w300-h400/IMG_20230807_205359.jpg" width="300" /></a></div>I didn't want to repeat the same errors that I had made in drilling holes that plagued the 900. On that effort, I had marked where I wanted the holes to be with a sharpie. Unfortunately, because of my inability to measure properly and the inability to drill properly, the holes were at bad spots. So I had to make the holes larger to get the openings to where they should be.<p></p><p><br /></p><p>I did some reading and found out about transfer screws. These are screws that go into the holes of a device that allow you to mark your other items for the proper drilling spots. Wow, what a simple concept and they work very well! Ordered 6x of the ones for 1/4-20 holes so that I could mark all the holes in the Parallax rings. They came from McMaster in 48 hours and I was ready to do some drilling.</p><br /><p><br /></p><p>On Monday after work, I was able to make the marks, do the drilling (yay for sharp bits), and was surprised at how well the hole placement worked. The screws dropped right into their holes and everything came together perfectly. See the picture above for the example of how it looks and compare to the view of the 900. </p><p><br /></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjxHdSLai4_JIJfcNcKd-FtFrBrwWLTh50v7A3rSTIHD8DoK9SgLGxx0M3yaY21CMGx6RI6_QoDYINFNxcfXRa1dHSsWUnCulOp0c71bkXNggNcP2YYz0jV6OKxT1_1irUw0K1FlzdOOJpMVmG0RoiVFBK0oJr3riwhhTxWGq2k4LnyzhbQKcKNV3t9jEo/s4000/IMG_20230807_205531.jpg" style="clear: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" data-original-height="3000" data-original-width="4000" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjxHdSLai4_JIJfcNcKd-FtFrBrwWLTh50v7A3rSTIHD8DoK9SgLGxx0M3yaY21CMGx6RI6_QoDYINFNxcfXRa1dHSsWUnCulOp0c71bkXNggNcP2YYz0jV6OKxT1_1irUw0K1FlzdOOJpMVmG0RoiVFBK0oJr3riwhhTxWGq2k4LnyzhbQKcKNV3t9jEo/s320/IMG_20230807_205531.jpg" width="320" /></a></div>By 9:30 that night I was able to put the scope on the GM8 and attempt to counterbalance it. The idea was to use the moon as a bright target to find infinity focus. Monday was pretty much the last shot to get it before the marine layer became too strong and would cloud out the week. <p></p><p><br /></p><p>Balancing the scope required four of the 21 lbs counterweights - all the way out at the end of the bar. The GM8 was very overweight. I was only using it as an assembly stand. </p><br /><p><br /></p><p>Once the moon had cleared the local horizon at 1 am, I was able to find it easily and then used a piece of paper to align the ground glass position with the moon. Even without a loupe it was easy to see the craters along the terminator. The cell phone pictures do not show the view as visible to my eyes.</p><p><br /></p><p>Locked down the focus position and was satisfied. Made a single picture of the status.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnE8rACcEeemzFe0lfFx1WhBVufUIvN-HPrbOcN08qxiWELUCUAhOwqw73mQKDimK3V0Dm5RYpk_cTht-h6rPscLLvUVF6zV-1coo3fYoSMD9TMgaVumxY00MT6bhVsk7Dd-Bnl-Y4Ox1F9VRcwSJKUG2G71THKUExh9DU5us59p_8FWqGLm0cMrBgnD4/s4000/IMG_20230808_011537.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="640" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnE8rACcEeemzFe0lfFx1WhBVufUIvN-HPrbOcN08qxiWELUCUAhOwqw73mQKDimK3V0Dm5RYpk_cTht-h6rPscLLvUVF6zV-1coo3fYoSMD9TMgaVumxY00MT6bhVsk7Dd-Bnl-Y4Ox1F9VRcwSJKUG2G71THKUExh9DU5us59p_8FWqGLm0cMrBgnD4/w480-h640/IMG_20230808_011537.jpg" width="480" /></a></div><br /><p><br /></p><p><br /></p><p>The next day I put the scope down and put it away. Snapped this reference picture of the rear standard so that I could note the position of infinity.</p><p><br /></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhUQ2FpAAbnBgczqesUaAPHM9W0olLaKBo1mP_CiEwX1kHOTRcK__XZRfPo55wte7jwtBN5aoc9ZkytbUv9PtxdZTI0nU2NuwycZUPV5SgiUTZUapXv1c-tuvfmbQ-eIQY7ToxtHZEBtFUPJiEMS1UBrvpccqJsS-M-efljRm1Pb5HCBEToakov0FR_-c8/s4000/IMG_20230809_193527.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhUQ2FpAAbnBgczqesUaAPHM9W0olLaKBo1mP_CiEwX1kHOTRcK__XZRfPo55wte7jwtBN5aoc9ZkytbUv9PtxdZTI0nU2NuwycZUPV5SgiUTZUapXv1c-tuvfmbQ-eIQY7ToxtHZEBtFUPJiEMS1UBrvpccqJsS-M-efljRm1Pb5HCBEToakov0FR_-c8/w300-h400/IMG_20230809_193527.jpg" width="300" /></a></div><br /><p><br /></p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-8654614120962197322023-08-04T08:47:00.000-07:002023-08-04T08:47:12.919-07:00Summer Project Progress<h2 style="text-align: left;">The 1200 lens project is coming together quickly.</h2><div><br /></div><div>I received the Parallax rings for the 1200 mm lens on Monday. They fit nicely - I will need to put an additional layer of cork or a thin layer of rubber to help with the grip on the lens. When I first put the rings on, the lens could slide out under its own weight. I put a temporary shim of some styrofoam padding to give a little more grab. Once the rings were in place I measured the center line of the rear standard and noted how much the lens needed to rise. Just like the 900mm, it needs 6 inches to meet the height of the rear standard. Luckily, I already have a solution in mind and I ordered the extruded aluminum tube just like last time. </div><div><br /></div><div>I put the bar assembly on a pair of jack stands just for the sake of keeping it at a decent working height and being able to access the screws both above and below the bar. I'm not going to keep it like this, just for the sake of testing. </div><div><br /></div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmH9p04ohidE1B4W9gE88_NWLq_psc_VWQmTvKFXl7fpkoUVkiL1ohnHLsG3Uiiy9BjEre4d0JAE6gAw_dLSDCWYQee7bbOchdcnwHwhbrdEAj1umnkCxlxyYjUhGF24KjxZYw5IEQH-hQTVt5ze3X-T6Y9ZdSNj8lx3DHybugqWg-FtrpMGtEUmF_LVM/s800/53085802015_2df59bbdcf_c.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="600" data-original-width="800" height="300" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhmH9p04ohidE1B4W9gE88_NWLq_psc_VWQmTvKFXl7fpkoUVkiL1ohnHLsG3Uiiy9BjEre4d0JAE6gAw_dLSDCWYQee7bbOchdcnwHwhbrdEAj1umnkCxlxyYjUhGF24KjxZYw5IEQH-hQTVt5ze3X-T6Y9ZdSNj8lx3DHybugqWg-FtrpMGtEUmF_LVM/w400-h300/53085802015_2df59bbdcf_c.jpg" width="400" /></a></div><br /><div><br /></div><div><br /></div><div><br /></div><div>It's heavy. I can see that I'll need a helper to put this up.</div><div><br /></div><div>I looked through the glass for the first time last night and saw that it's already blackened on the inside. Some flecks of paint have fallen onto the inner surfaces. Once I get this assembled, I may consider unscrewing the halves and cleaning it up. I'm also wondering if there is an adjustment that will need to be made between the halves. Will see how the images look once I can get this mounted on a G11 to look at the full moon. I will try projecting an image onto a sheet of foamcore to know the proper backfocus. Once I have this dimension, I will order a custom tube for the back to span most of the distance. The last bit will be bridged with wide angle bellows so that I can put an eyepiece or film holder in the rear standard and be able to bring both to focus.</div><div><br /></div><div><br /></div><div>On Thursday:</div><div><br /></div><div><br /></div><div>I found out that the metal bar will be waiting for me when I get home today after work. This reminds me that I will need to get the hardware to bolt it together. I am extremely lucky that I can buy the hardware at a discount and have it waiting for me to take home at the end of the day.</div><div><br /></div><div>I have not had the motivation at the end of the day to put the lens on a mount to be able to check for focus at infinity. I would like to think that I will get to it tonight - or at least while viewing the moon will be an evening activity.</div><div><br /></div><div>I looked at the fig tree this morning and I'm going to need to cut it back just to properly view Polaris. Long term project will see this tree and the mandarin going away in the favor of a larger custom shed within 18 months so I'm not too worried about trimming a few branches now.</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjRvcswWInxIc3AprLT67HY0A4AyGkAq0sm5e1qlBr37gnPivD-LB7dQ-4odB6_Ss9ApmDhsT2WKe4E79TIuaCraqK-_Jm_UQHjTP5xGvsiCiQXnACycZhlxu85I2x05d_mDp6n9uiqU9Y34sF3rIR8Uvv2eacZ2W549fQYMesStaFhmHWKTFkM5fdUktg/s725/image.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="725" data-original-width="533" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjRvcswWInxIc3AprLT67HY0A4AyGkAq0sm5e1qlBr37gnPivD-LB7dQ-4odB6_Ss9ApmDhsT2WKe4E79TIuaCraqK-_Jm_UQHjTP5xGvsiCiQXnACycZhlxu85I2x05d_mDp6n9uiqU9Y34sF3rIR8Uvv2eacZ2W549fQYMesStaFhmHWKTFkM5fdUktg/w294-h400/image.png" width="294" /></a></div><br /><div><br /></div><div><br /></div><div><br /></div><div>The next big star party is in September. I'm hoping to have most of this project completed by then - the big unknowns are the metal tube dimension and how the transition from an 8 inch diameter circle to a 160mm square will be accomplished. One option is to get some sheet metal and cut it with a sabre saw. It'll be ugly but will work fine. Another option is to get a professional-look with a 3d printed truncated cone. That will probably cost $300 but will look the best. I think that could be a second step depending on how it goes.</div><div><br /></div><div><br /></div><div>There are many projects that are on pause that have something to do with astro:</div><div><br /></div><blockquote style="border: none; margin: 0px 0px 0px 40px; padding: 0px; text-align: left;"><div>1. hypering fomapan - stuff to do to improve the process (thermal control) and to test the results.</div><div>2. cutting the roll of aerographic film (aviphot 200) into sizes to use in the holders (and hypering depending on performance) - depends on blacking out the bathroom so that I can work in total darkness.</div><div>3. peeling another few layers off the polar alignment onion - requires time and a view of polaris at home (see above picture)</div></blockquote><div><br /></div><div>I looked at the original scan of the TMax and I can see two things for improvement:</div><div><br /></div><div>1. slight trailing - there is a tiny amount of oblong stars in the central region where the image is sharpest. I would say that the length of the trail is maybe 2-3 pixels - about 8-10 microns at the surface of the film. Most of the star images outside of the sharpest region are not tight enough to show this error. This trailing could be field rotation or it could be the balance issue that I've attacked before. What it tells me is that I can refine the balance a bit more than I have already.</div><div>2. coma is not centered - this tells me that the optical center of the lens is not centered on the rear standard. I will try to figure out which way they need to move to bring it true. </div><div><br /></div><div>I am tempted to send off the remaining C41 and E6 film from the last star party to get developed rather than waiting for myself to mix the chemicals and do it. I keep trusting my future self to do the effort. There's a lot of emotional baggage that comes with putting all the chemicals into the kitchen, handling the film, and then putting it all away. It's a very obvious focus of my energy onto something that has nothing to do with house work or garden work. It's a thing that I have to rationalize and manage. </div>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-12962522533083487192023-07-31T07:38:00.003-07:002023-07-31T07:38:26.743-07:00Barnard E on Tmax 400 at GSSP 2023<p> Finally Scanned the Tmax</p><p><br /></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiY5FJ0F05su544PA42Wngex6vHE-pibNqv0tJDRChTPBcKPkvXYKS5-UNaJ8z2gau0-QoMmA9zPKu2eqsSzPkhMIzRWYX5u8RcczKTgDhFmMf9tUPe87URdzIGj5i6TnEe8MNDdO4iSvHvEGjXaDLM9j3DC-wby2EOkcADq9qp4xxnCKzOJS7EU3R0jyg/s800/53083311450_407e4b1383_c.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="634" data-original-width="800" height="318" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiY5FJ0F05su544PA42Wngex6vHE-pibNqv0tJDRChTPBcKPkvXYKS5-UNaJ8z2gau0-QoMmA9zPKu2eqsSzPkhMIzRWYX5u8RcczKTgDhFmMf9tUPe87URdzIGj5i6TnEe8MNDdO4iSvHvEGjXaDLM9j3DC-wby2EOkcADq9qp4xxnCKzOJS7EU3R0jyg/w400-h318/53083311450_407e4b1383_c.jpg" width="400" /></a></div><br /><div><br /></div><div><br /></div><div>https://www.flickr.com/photos/smigol/53083311450/<br /></div><div><br /></div><p>The only thing I scanned last night - had to re-learn how to scan, update Silverfast, update photoshop, and update lightroom.</p><p>Jim Cormier suggested using Tmax 400 for a few reasons: </p><div><ul style="text-align: left;"><li>It's available in 4x5</li><li>At durations up to 10-15 minutes is faster than Acros</li><li>Beyond this duration it holds up well</li></ul></div><div><br /></div><div><br /></div><div>I am surprised that two or three satellites still showed up on the film. It might be due to the 400 speed catching the bright objects easily. There's a cat whisker on the film, plus some dust and a scratch or two. I can also see two of my fingerprints - evidence of sweaty fingers in the dark bag. Not a big deal. The satellites don't bother me at all because they actually help frame the dark nebula of interest.</div><div><br /></div><div>As I say on the flickr page, my notes from the event suggest that I was shooting this at F6. However, the coma in the corners suggest that it might be shot wide open at F5.6 (or whatever this lens can do). I will take a look at the lens itself to see if the aperture has been changed in the two months since the trip.</div><div><br /></div><div>What I find interesting about this shot: </div><div><ul style="text-align: left;"><li>As a two hour exposure - no trailing or field rotation visible, even with the full scan. </li><li>The corner coma is balanced in each corner, letting me know that there is no lens sag and that the field of view is centered. I will need to confirm focus 1/3 out from the center to minimize the coma. </li><li>This is an unfiltered shot - no yellow filter to tighten the stars. Might be useful to revisit this target at Calstar with a filter to compare results. </li><li>Also, I think that I can see film grain - evident at the full size scan which resolves to 4 microns per pixel. The full size version visible on flickr does not show the grain. If anything, it might show the mottled background of barely resolved stars. </li></ul></div><div><br /></div><div>Pretty happy with how it looks and this bodes well for the color shots.</div>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0Adin, CA 96006, USA41.1349427 -120.97854212.824708863821158 -156.134792 69.445176536178849 -85.822292tag:blogger.com,1999:blog-8481375458403073225.post-9614712205643978972023-07-14T08:03:00.006-07:002023-07-14T08:03:39.543-07:00What to call this next project?<h4 style="text-align: left;">Back Breaker?<br />Hernia Maker?<br />Last Straw?</h4><p><br /></p><p>I received the lens for the next project. Arrived in great shape. On first inspection, the glass is good, I don't see as much yellowing as I had expected.</p><div class="separator" style="clear: both; text-align: center;"><br /></div>Here's a quick view of the box size in the back of the prius<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlKu94EtSyGJznToTO5BmE3SBaGea0ABCMpFpB_GTFEVVuh4w40hNWOC4AmUW3SyWeeJINQOAqC4wgcR2UikHHbI47MN5gb2rlclB5FobzDzz6dakcapu8z3K8_ewVZH2FxoueQwEyuxIvHFxyWfzokdDnbHdDmtmLyERlmkMr8ihUZznMrHwWt1MOs0U/s4000/img_20230713_125943_53043261902_o.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3000" data-original-width="4000" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjlKu94EtSyGJznToTO5BmE3SBaGea0ABCMpFpB_GTFEVVuh4w40hNWOC4AmUW3SyWeeJINQOAqC4wgcR2UikHHbI47MN5gb2rlclB5FobzDzz6dakcapu8z3K8_ewVZH2FxoueQwEyuxIvHFxyWfzokdDnbHdDmtmLyERlmkMr8ihUZznMrHwWt1MOs0U/s320/img_20230713_125943_53043261902_o.jpg" width="320" /></a></div><br /><div><br /></div><div>Once I put the lens into the shed, I needed to take some pictures for size.</div><div><br /></div><div>With no sense of scale:</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiyDtCj84cI5-7jC36H2v1beagGMD3nVHulETWQ5Avx-GimM4S36RhF5lNqfV0EslHzBH_z_V9ekD-xanQ49D10h9wmNrKWDcfPc6pmXwkumUcigdwUOU1cpXXvoZYBNRrMFw0KzP6n1xh7c5s3mhcv4vemR0yz2TVt8Fa9sfJDdiEbWRi-rUmEYUsHozU/s4000/img_20230714_063656_53044579392_o.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiyDtCj84cI5-7jC36H2v1beagGMD3nVHulETWQ5Avx-GimM4S36RhF5lNqfV0EslHzBH_z_V9ekD-xanQ49D10h9wmNrKWDcfPc6pmXwkumUcigdwUOU1cpXXvoZYBNRrMFw0KzP6n1xh7c5s3mhcv4vemR0yz2TVt8Fa9sfJDdiEbWRi-rUmEYUsHozU/s320/img_20230714_063656_53044579392_o.jpg" width="240" /></a></div><br /><div><br /></div><div>Now with a gallon of paint:</div><div><br /></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg80lhx3PzxAFtBhn0kJXV_9axuv3HLCVztEw645XUfdoQVyLw3_ZArLyYrQ_nTQARc5qGtiaA_p1bWuPMSUD3FE4NevrFcjrD1KqI0soekAP-xVQ1P2QBjIx7BQiGRR7c1Xw0EBmtTRGQ-IwU_cM7469fDvU8nuytyJQnjho-S_LrnyOD2iIb1umSJk_0/s4000/img_20230714_063706_53045342679_o.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg80lhx3PzxAFtBhn0kJXV_9axuv3HLCVztEw645XUfdoQVyLw3_ZArLyYrQ_nTQARc5qGtiaA_p1bWuPMSUD3FE4NevrFcjrD1KqI0soekAP-xVQ1P2QBjIx7BQiGRR7c1Xw0EBmtTRGQ-IwU_cM7469fDvU8nuytyJQnjho-S_LrnyOD2iIb1umSJk_0/s320/img_20230714_063706_53045342679_o.jpg" width="240" /></a></div><div><br /></div>Now with a one quart Mason jar:<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDX9ObHDefTw2sVR5QSkFAnSK7NRrfERelazTMn3ng69a3BA5TAwrA4fdECU8mikDELSfyp5iMuuyfumcsE8qB6E6J5a1i3-IR0VkKXfOwuvUFgKWLCx7Sv_chdTo9xdqatw5RiuDBc1wElFjtR2PqBEdWXjtCn5AVncb84OqfqE0ahv11lDEtdJshW54/s4000/img_20230714_063723_53045657108_o.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgDX9ObHDefTw2sVR5QSkFAnSK7NRrfERelazTMn3ng69a3BA5TAwrA4fdECU8mikDELSfyp5iMuuyfumcsE8qB6E6J5a1i3-IR0VkKXfOwuvUFgKWLCx7Sv_chdTo9xdqatw5RiuDBc1wElFjtR2PqBEdWXjtCn5AVncb84OqfqE0ahv11lDEtdJshW54/s320/img_20230714_063723_53045657108_o.jpg" width="240" /></a></div><br /><div><br /></div><div><br /></div><div>This is the picture provided by the seller showing the front optic. The dots seem to be reflection of the LED panel. The color is mostly from the reflection on the coating. </div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjLCvrvk38RLqhU4VMxe9yDDLJI_iGD0xBVBp0GsdqD9E7CLAgm06TEXJTrTo476z62jaFLpn0PpXiu2fDFgNWHN-4nI_-m-pmOQbC97NXqCEiqEI7mYEqrt07CFl4nIprou_Ydi65hNuBHb-AIeUbZLZZRhm9xmmdIak2rHY7WeH0TLQJ2EjHLUjCo3oI/s340/big-lens_53043703701_o.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="270" data-original-width="340" height="254" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjLCvrvk38RLqhU4VMxe9yDDLJI_iGD0xBVBp0GsdqD9E7CLAgm06TEXJTrTo476z62jaFLpn0PpXiu2fDFgNWHN-4nI_-m-pmOQbC97NXqCEiqEI7mYEqrt07CFl4nIprou_Ydi65hNuBHb-AIeUbZLZZRhm9xmmdIak2rHY7WeH0TLQJ2EjHLUjCo3oI/s320/big-lens_53043703701_o.jpg" width="320" /></a></div><br /><div><br /><div>Glass is 190mm in diameter. Specs are 48 inch focal length, F6. There appears to be a ring with f stops listed on outside of the lens. I don't think the blades are still there.</div><div><br /></div><div><br /></div><div>First step will be to measure the outside and get custom rings made. Once I have these, I can mount the lens and start taking measurements for backfocus and how much rise will be required to accommodate a film back. </div><div><br /></div><div>Rather than having bellows for the whole backfocus, I plan to get an aluminum tube to span most of the distance and then only put a wide angle bellows bag on the back to go to the rear standard. It's possible that I may get another changing bag and just use that as the bellows rather than having a set made.</div><div><br /></div><div>The longest dovetail bar I can get is 24 inches from Losmandy, so I'll need to make up the rest of the backfocus with a monorail. The Toyo G rail works well and I will probably make that again.</div><div><br /></div><div>I expect that the project will take at least 8 months to complete, possibly in time for next galaxy season.</div><div><br /><div class="separator" style="clear: both; text-align: center;"><br /></div><br /><p><br /></p></div></div>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-9304502790947567722023-07-10T07:34:00.006-07:002023-07-10T07:34:47.241-07:00Notes from GSSP 2023<h2 style="text-align: left;">Quick summary before I forget the details.</h2><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgC8H8DpNOpj14sNJxtrovI3Bm3uMo1pJyL7nTb2TG4qRBHLVzGWISxl8SSXU_eXnp6tIBe5qkyDb2EErDo3nrU-Voo63IhhTWK3yX1iANcgDzn7gkMhINyw2vruV68cZR5UM0pxict5fviK0Ts__JVCfNq6qAVpOnhGVCmMlmSrhkuXlSuBrI6qRGbz7Q/s958/gssp%20forecast%202023.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="668" data-original-width="958" height="279" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgC8H8DpNOpj14sNJxtrovI3Bm3uMo1pJyL7nTb2TG4qRBHLVzGWISxl8SSXU_eXnp6tIBe5qkyDb2EErDo3nrU-Voo63IhhTWK3yX1iANcgDzn7gkMhINyw2vruV68cZR5UM0pxict5fviK0Ts__JVCfNq6qAVpOnhGVCmMlmSrhkuXlSuBrI6qRGbz7Q/w400-h279/gssp%20forecast%202023.png" width="400" /></a></div><br /><p><br /></p><p>Wednesday looked iffy on the charts and yet it turned out to be good at night.</p><p><br /></p><p>Arrived at 4:38, missed the gate people.</p><p><br /></p><p>Set up near the standard crew. Made sure that there was enough room between myself and others.</p><p><br /></p><h2 style="text-align: left;">Had problems during the nights:</h2><p><br /></p><p>Digital wide field had massive cable snags that caused a variety of issues. Mostly due to cables preventing mount movement and the QHY10 being unplugged. It was so dark that I did not see the snag until very late. Wires were re-routed on the following day on Thursday.</p><p><br /></p><p>Thursday night the wide field stopped communicating properly for performing focus. Stopped trying late in the evening and on the following day Friday I found that the ethernet cables were wired backwards. Also, I found that the QHY10 was partially unplugged.</p><p><br /></p><p>Friday night was great and the wide field worked well, same with Saturday night. Need to schedule focus runs more often somehow. Either that or profile the focuser so that it can change during a run.</p><p><br /></p><p>The 900mm also had an issue with the Dec not slewing properly on Wednesday. It could have been due to a cable snag as well. Dec was remeshed on the following day on Thursday.</p><p><br /></p><p>On Thursday night, the 900 was able to guide well for the first 2 hour exposure but would not slew properly to the second target. The RA complained of being too tight. It would not slew back to CWD. During the next day, the RA was remeshed and the end play increased by 1/8 a turn. Also, the goto and slew speeds were dropped to 350.</p><p><br /></p><p>On Friday night, the 900 performed well. PHD2 guiding analysis complained about polar alignment being off. Polemaster was good when checking earlier. PHD logs showed that it was 22 arcminutes off from ideal. There will likely be trailing or field rotation.</p><p><br /></p><p>On Saturday night, the 900 was not used as the Kendrick box failed to switch on. I think that the relay on this one died. It's possible that the relay needs to be replaced. Given the issues with it, I wonder if a different one should be put in its place. Will try powering it up again at home with the 13.8 V. This may reset it. The voltage at the time was likely 12.8 V, hardly enough to fail the relay (15V).</p><p><br /></p><p>The monorail on the newly rebuilt G11 worked well on each night. </p><p><br /></p><p>Shot E100 on each setup. Only the Monorail got TMax 400 for the Friday night. First was NGC 7000 for 3 hours. Then B 142/143 for 2 hours. Possibly the second shot is ruined because my neighbor Moshen was doing flats at 4 am and may have spilled light.</p><p><br /></p><p>Weather was cool - daytime temps did finally climb to near 80. I should have brought a pair of shorts. Wore the same jeans during the daytime and and the same lined jeans at night. Night time temps ranged from low 40s to low 50s. Wednesday had poor transparency and seeing, Thursday was the best of the whole weekend, Friday had smoke from Canada which was interesting, and Saturday looked so bad on Astropheric that most of the field left during the daytime. The afternoon and early evening featured strong winds. That night the sky did not fully clear until after midnight.</p><p><br /></p><h2 style="text-align: left;">Shots attempted:</h2><p><br /></p><p>E100 on 400mm at F6 on IC1396 (2:30 hours), NGC 7000 (2 hours x 2), Barnard 142/143 (2 hours), Cocoon nebula (2 hours), Swan Nebula (2 hours).</p><p>E100 on 900mm NGC 7000 (2 & 3 hours). Others were attempted, but need to confirm.</p><p>Tmax 400 on 400mm at F6 on NGC 7000 for 3 hours and then Barnard 142/143 for 2 hours.</p><p><br /></p><p>Digital wide field only was NGC 7000 and Barnard 142/143 on the two nights.</p><p><br /></p><p>Will need to confirm with guide logs.</p><p><br /></p><p>No vacuum used.</p><p><br /></p><p>Only the old E100 was used, nothing new. No minus green filter used.</p><p><br /></p><h2 style="text-align: left;">Activities during the days:</h2><p><br /></p><p>After arrival, I brought Iz her old film from 2019. I set up the giants camp chair in ryan's living room. I also gave Ryan first dibs on the film tumblers. She passed them on to Brian who was very enthusiastic about them. Gave Iz the etone loupe since it isn't my cup of tea - doesn't mag enough. Gave away the partial brick of e200 to Iz and Ryan. I offered the reflector and boom to Ryan and she said that she did not need them as she already has them. At the end of Friday we used them to take pictures and they stayed in the collection.</p><p><br /></p><p>I donated the star atlas and the focuser to rich ozer for the door prizes. This helped the event. I think that I will do more of the same in the future. In thinking about the past, with the donations of money, the artwork, and then these items, I've given a lot to the event.</p><p><br /></p><p>The rings did not go. Nor the dovetail plates. These will all get recycled.</p><p><br /></p><p>I picked up an easy guider - flashing reticle eyepiece. That way I can someday try manual guiding if I decide to be crazy.</p><p><br /></p><h2 style="text-align: left;">New people met:</h2><p><br /></p><p>Met Scott Posey - a solar guy of great knowledge. Very interesting fellow, reminds me of Dave.</p><p><br /></p><p>Met Adam - an interesting dude that was a little quiet but finally became a good talker.</p><p><br /></p><p>Met Moshen Chan - my next door neighbor that was working with harmonic drives and CMOS cameras. We talked a lot about what he's doing. </p><p><br /></p><p>On Thursday, I drove Moshen, Brian, and Ryan to Burney Falls where we had a nice trek down and back. Snapped a bunch of pictures. Shot on Portra and on E100. I also used the 75mm Nikkor. That lens has decent movements as far as I can see. It's possible that I may have left it unsecured at the top edge for a few shots, leading to an unintended front tilt. May have been hidden due to front drop.</p><p><br /></p><p>I shot the dry plates on Friday at the end of the day. Used the old lens. Shutter was messed up again, though, it would not close at 1/5. So, most of the shots will be blurry and over exposed. When I develop there will be a need to watch and pull the plates out fast.</p><p><br /></p><p>With the experience of shooting, then loading the plates, then shooting, it was slow. The people had a good time. The effort to corral everyone was left to Ryan and Iz. They also helped with the lighting and posing. It was a great collaboration and all I did was focus and frame. There was one moment where I did not flip the dark slide, leading me to wonder which side was exposed. Hopefully I did not double expose it!</p><p><br /></p><p>In the future, I would like to use another lens - or make sure that the old kodak shutter is accurate. </p><p>Also, I need to get a good estimate of metering blue light. Maybe a blue filtered meter would be good to try. </p><p>Juggling exposed plates with unexposed plates in the bag was a pain, too. Will think about how to manage these in the future. </p><p>Lastly, I would like to have two holders so that more shots could be done at one time.</p><p><br /></p><p>Will need to get more supplies prior to Calstar. Possibly 20 plates.</p><p><br /></p><p>There was talk about trying tin types in the future.</p><p><br /></p><p>https://zebradryplates.com/how-to-use-zebra-dry-plate-tintypes/</p><p><br /></p><p>Tintypes would be interesting, but require a setup for developing. </p><h2 style="text-align: left;">Closing thoughts:</h2><p>During my final teardown, the tent ripped in the strong wind. I salvaged the poles and tossed the rest.</p><p>I slept in the car that final night. It was not bad to do this. I felt that being unable to turn onto my side was not as much of an issue as expected. On the other hand, getting up to check on the scopes in the middle of the night was easy to do. What was not fun was the feeling of isolation with the windows rolled up. I am not sure if I would want to sleep in the car as a regular choice. </p><p><br /></p><p>I do want to slim down the stuff that I bring.</p><p><br /></p><p>Just sleeping in the car would remove several things from the required packing list. I would be able to eliminate the tent, cot, stakes, and tarps. Easy up with shade cloth would still be required and would likely be something to erect. I would not need an additional blanket and probably not the sleeping bag. I would have some issues with reloading film, but that can be managed by standing or using the tables. I would also have some issues with not having the space to sort clothes, food, and water. May actually be a moot issue.</p><p><br /></p><p>Rolling over may be solved by putting a layer of padding on the chair which would allow a flatter sleeping surface on the passenger side.</p><p><br /></p><p>These are things that can be tried at Calstar. If I can make it through 4 nights sleeping like this then it will really open up other possibilities.</p><div><br /></div><p><br /></p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-36577003415766303042023-07-07T07:32:00.002-07:002023-07-07T07:33:05.226-07:00Sharing a video from Brian from GSSP 2023<p> </p><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="358" src="https://www.youtube.com/embed/Hd-U-oOjkts" width="603" youtube-src-id="Hd-U-oOjkts"></iframe></div><br /><p></p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-59167645086865910172023-06-30T09:42:00.002-07:002023-06-30T09:42:28.146-07:00Last biggest lens<p> I decided to pull the trigger on this last, big lens.</p><p>I believe that this will be the last big project that I can tackle.</p><p>It will push my skills to the limit and I expect that the first light will probably be in the summer or fall of 2024. </p><p>I see that the Losmandy Titan is no longer available as a stand alone mount. It exists only as an upgrade to the RA axis for a G11. This might be the only option to support the project lens outside of Astro-Physics or Paramount hardware.</p><p>That being said, I will be putting the rest of the effort this year into:</p><p>1. Tweaking the performance of the existing mounts and large format setups to improve focus and tracking</p><p>2. Purging down underused gear and cables for astro and photography</p><p>3. Optimizing my camp setup to remove the use of unrequired luggage</p><p>4. Planning for the Eclipse trip</p><p>5. Testing the film Hypering with times and emulsion</p><p>6. Making a dark safe room to process plates and uncut sheet film.</p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-44104484403299543912022-11-30T19:57:00.005-08:002022-11-30T19:57:59.770-08:00First lights with the 900mm f8<p> I posted the first light pictures last night on the <a href="https://flic.kr/s/aHBqjAgQki" target="_blank">flickr</a> and then put them on <a href="https://www.cloudynights.com/topic/852935-shooting-some-fomapan-200-in-4x5/" target="_blank">CN</a>.<br /><br />I'm pleased enough with how they look.<br /><br />I think that I'll eventually try the acros with this setup. Roll film and the sheets.<br /><br />It was clear and cold that night. I'm glad that I finished the testing that I wanted to do.<br /><br />Found out that the first light setup of the scope was too far east biased when pointing to the west. It was the reverse when pointing to the east. This is why the tracking was awful when looking to the Pleiades.<br /><br />The shots from Saturday are full of details. Lots to learn. <br /><br />The scope balance was off so only the images shot to the west are any good. The east side shows heavy trailing.<br /><br />The focus test with the bahtinov mask left a lot to be desired - the stars were not bright enough to show diffraction spikes. The only light that showed up was a flashing beacon on a passing aircraft. It appeared to be right on the money. </p><div class="separator" style="clear: both; text-align: center;"><a href="https://live.staticflickr.com/65535/52533520280_19d22aea38_c_d.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="800" data-original-width="631" height="800" src="https://live.staticflickr.com/65535/52533520280_19d22aea38_c_d.jpg" width="631" /></a></div><br /><p><br /></p><p><br />This lets me know that focusing with the ground glass at 10x is pretty good. I like the e-tone loupe for daytime work as it has a nice eyecup. It’s a little too narrow of a view for the stars. I prefer the Adox 10x for stars because there’s a larger field of view which catches the little stars when they pop into focus.<br /><br />Scanned the film and did very little processing. Scanned the full 4x5 at 2400 dpi and the central crop at 6400 dpi.<br /><br />There appears to be a little softness in the upper left corner on the full sheet view. That softness may be from film curl. It's unlikely to be from the lens field. There's no corresponding distortion on the other side, so I can rule out field rotation.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://live.staticflickr.com/65535/52533046336_6280f11064_k_d.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="800" data-original-width="636" height="800" src="https://live.staticflickr.com/65535/52533046336_6280f11064_k_d.jpg" width="636" /></a></div><br /><br />The detailed center portion of M39 shows the nice, round stars that appear. There are quite a lot of them and they sit just above the grain. I don't expect any extended objects to appear on this film, it doesn't respond well enough to the low light levels. The stars show up so well because of the aperture.<p></p><p>It's a splendid view:</p><div class="separator" style="clear: both; text-align: center;"><a href="https://live.staticflickr.com/65535/52533520410_6e91235b81_o_d.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="800" data-original-width="798" height="800" src="https://live.staticflickr.com/65535/52533520410_6e91235b81_o_d.jpg" width="798" /></a></div><br /><p><br /></p><p> </p><p>This lens is designed for 9x18 inch film, so it has a massive image circle. More than enough to put two 4x5 sheets side by side or to put a 5x7 back or even 8x10 back on it. <br /><br />These would require a whole new bellows and standard. Luckily, the way it was built is not too hard to accomplish.</p><p>When I finally get to using the aerial film on a roll, then I can shoot the bigger formats if I invest in the hardware.</p><p>Still to be tested:</p><p>Film flatness will be checked by rotating the back to see if it follows the turn. Also, will try different holders. I know that the holder #1 had the curl (if it is that). </p><p>Tune the weight balance in RA and DEC to get more predictable behavior from the mount. As it was, the RA balance was lopsided in the above examples and while I can reproduce this, I would rather not depend on improper setup to get the results.</p><p>Also wish to run the PHD2 tune process to get the ideal calibration and guiding settings. During another session I saw that DEC wanted to wobble and tried turning the aggressiveness down a bit.</p><p>Once these have been tuned a bit under mooney skies, I will run up to Montebello and shoot Orion on a sheet of E100.<br /><br /></p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-69715699667142557772022-11-28T21:44:00.005-08:002022-11-28T21:44:55.532-08:00Aperture Matters - Getting to First Light<p> On Saturday, I got back to work on the Aperture Matters project.</p><p>Achieved first light!</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg91PksLCJligx_CfpSw84EJzzcn9mR-lduLlBHxPtT1uVxKKbTzats97LGcjZ2O1cwWTLKk_u1ZuFdbz9tx_T745YavClxzGu0_I2VFQK1mgZqPN9RE4yGr91A55eOG_kdSX4Anl2EObMEUAycVQ80_ZZbT2_gL3qn5LE0i1v9Mqw00xJ644bw869w/s4000/first-light_52526000074_o.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg91PksLCJligx_CfpSw84EJzzcn9mR-lduLlBHxPtT1uVxKKbTzats97LGcjZ2O1cwWTLKk_u1ZuFdbz9tx_T745YavClxzGu0_I2VFQK1mgZqPN9RE4yGr91A55eOG_kdSX4Anl2EObMEUAycVQ80_ZZbT2_gL3qn5LE0i1v9Mqw00xJ644bw869w/s320/first-light_52526000074_o.jpg" width="240" /></a></div><br /><p>But first, the back story:</p><span><a name='more'></a></span><p></p><p>When I started back on the project on Saturday afternoon, the epoxy had set properly on the bellows frame. It was bonded to the ring and to the riser just as expected. Neither will move now until it's wrecked. I'd probably have to soak it in acetone and hack at it with a blade to separate it. This is good because the bellows pull on the frame especially at zenith.<br /><br />The bellows end needed slight modification as well since the clearance on the frame was reduced. Dremel tool was used to provide clearance and they snap in place now.<br /><br />Then I made a double layer of black felt and black craft foam paper to be the light seal between the frame and ring. Wrapped the extra material around the edges to ensure light-tightness. A combination of adhesive and hot glue was used to tack it in place while it cured. </p><p><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfqE4Vi_iZrIB07WmVVeV5nEcgJl-DDXAQhY5Vq2Nhe3e8zw2gG4ARjEnCO7LlOc4S5Ppkp0G4Z6QelekzVbEdGhHu05yNKJ8sYnCa2YsMNptb50YUOGRyWTK7YGzZsJUfN0LIueY087UZZskZTKjinqyAnNYznyT13UN2UBHds0sLi7Jb-CG9YI_e/s4000/img_20221126_145352_52524953177_o.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3000" data-original-width="4000" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfqE4Vi_iZrIB07WmVVeV5nEcgJl-DDXAQhY5Vq2Nhe3e8zw2gG4ARjEnCO7LlOc4S5Ppkp0G4Z6QelekzVbEdGhHu05yNKJ8sYnCa2YsMNptb50YUOGRyWTK7YGzZsJUfN0LIueY087UZZskZTKjinqyAnNYznyT13UN2UBHds0sLi7Jb-CG9YI_e/s320/img_20221126_145352_52524953177_o.jpg" width="320" /></a><br /><br />In order to do this properly, I removed the lens to do all the fitting and then struggled to get it back into the rings. What a heavy beast!<br /><br />Afterward, I put the guide scope and red dot finder on the top of the assembly.<br /><br />Mounted the whole thing on the GM-8, wired up the dew heaters and guide camera, and waited for dark.<br /></p><p></p><p></p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhUSFWcIQUHPPtMLPQFlB1IY549JH2Xc8C763l8dJ5KKuMHTICu9YzhBrd7FuEbyHJ0y3XmX1Mig48Faz8wAxZFVLdViK02Fb1jEvSdTEJgDG0YQml6R6mNAsf50ZjqkfOKFzHUq-Oo6_vP3BYc6hqEJ5ZmN4mwXVFjXM-kZ4aVdjLLZgiyVRRM4ib8/s4000/guide-scope-and-finder_52525900020_o.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhUSFWcIQUHPPtMLPQFlB1IY549JH2Xc8C763l8dJ5KKuMHTICu9YzhBrd7FuEbyHJ0y3XmX1Mig48Faz8wAxZFVLdViK02Fb1jEvSdTEJgDG0YQml6R6mNAsf50ZjqkfOKFzHUq-Oo6_vP3BYc6hqEJ5ZmN4mwXVFjXM-kZ4aVdjLLZgiyVRRM4ib8/s320/guide-scope-and-finder_52525900020_o.jpg" width="240" /></a></div><br /><p><br />A quick trip to the store and I picked up an 8 inch square aluminum pan that's used for leftovers. This would become the shutter for backyard testing. $7 for three pans, much cheaper than other solutions. Bummer that it's square, I'll eventually have to find a circular cake pan to modify.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhAwbHccf2SlmYP71OrRIhudCDiBJSDu5NgrQq3-8tTeOvBc5UZqlEW-QlbIML8PFdEpgOm8P6Q5c-1t__v4efYhxxcig60yaeVkH9P-eIHhQMEMEFHA24gL665_Yr3J8IZglKZpGxI_3MNH0zHtd7zv-eZiWxuTsTBMKng-atTeoTo7c_VL_M5053r/s4000/patiently-waiting-for-dark_52525570576_o.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhAwbHccf2SlmYP71OrRIhudCDiBJSDu5NgrQq3-8tTeOvBc5UZqlEW-QlbIML8PFdEpgOm8P6Q5c-1t__v4efYhxxcig60yaeVkH9P-eIHhQMEMEFHA24gL665_Yr3J8IZglKZpGxI_3MNH0zHtd7zv-eZiWxuTsTBMKng-atTeoTo7c_VL_M5053r/s320/patiently-waiting-for-dark_52525570576_o.jpg" width="240" /></a></div><br /><p><br /><br />A crescent moon was low in the sky which made it easy to align the finder and guide scope to the same point. The moon was a good target for getting focus as well, since it is so bright and the edges of the terminator are crisp and sharp. Could readily see some of the alpine regions near the mares.<br /><br />Slewed to Vega, checked focus with the loupe and was satisfied with centering and focus repeatability under the loupe. Did not see purple fringing on Vega with the 6x loupe.<br /><br />Trained PHD2 in the east, then started tracking on the target for first light.<br /><br />First light session was:<br /></p><ol style="text-align: left;"><li> M39 - open cluster north of Deneb - it's in the milky way as well. This should show a large collection of stars for focus evaluation. First shot was 45 minutes.</li><li> M39 with Bahtinov mask laid on the front element. It should show the diffraction spikes. 60 minutes</li><li> Flipped mount, new target was the pleiades. Refocused with the loupe. Replaced the mask and then another 60 minutes.</li><li> Last shot, Pleiades with no mask in place, another 60 minuntes.</li></ol><p><br />All shot on Fomapan 200. This film has poor reciprocity characteristics which works to the advantage of the testing - I can run a long exposure for tracking purposes without having to worry about sky fog.</p><p><br />Previous backyard testing was with TriX at 10 to 20 minutes at f5.6. Given the reciprocity stats of TriX, this would have been a metered exposure of 1 minute. Plugging these values in for ISO 200 and the loss of an F stop, the calulator suggested that the Foma needed an exposure of 87 minutes to match the TriX. This is why I opted for the 60 minutes as the exposure times for first light in the backyard. Should come close to sky glow limits while not keeping me waiting for too long.<br /><br />Could have developed the film on Sunday, chose to wait and to put the scope away as we'll be facing another bout of rain coming this week.<br /><br />The GM-8 mount tracked very well, given the over-loaded state of holding the big assembly. </p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBprnipNZIyFIVPBnERlhyZRjzcML0z-jCSJsNbraO4rEEH_bqUl-AaETfguWfnDESm6t89LRdKkcujiTWWXy7d0xLcOCxRUD9O1LiFaqE03TeMUYGxCQu_5j7BSsJIfhpp5B1g_J6YN1JlWGgqmJoReRO2uFl3srre2SLEQQiL3To-vHUPq_N7vSI/s4000/img_20221126_192001_52525720526_o.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3000" data-original-width="4000" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBprnipNZIyFIVPBnERlhyZRjzcML0z-jCSJsNbraO4rEEH_bqUl-AaETfguWfnDESm6t89LRdKkcujiTWWXy7d0xLcOCxRUD9O1LiFaqE03TeMUYGxCQu_5j7BSsJIfhpp5B1g_J6YN1JlWGgqmJoReRO2uFl3srre2SLEQQiL3To-vHUPq_N7vSI/s320/img_20221126_192001_52525720526_o.jpg" width="320" /></a></div><br /> <p></p><p>I've not weighed the setup yet, but from the heft, I would estimate 35-40 lbs. The GM-8 has the gearbox upgrades and I've lowered the slew speeds to reduce the stress. Guiding was great when pointing to the west. It was not as great when pointing to the east. PHD2 log analysis shows the scatter plot on the east as being wider with more RA corrections. I believe this would be from a lack of east bias. Most of the RA moves were to the east during these exposures. Future use would probably be on a G11 and I have a solution for constant east bias for those mounts.<br /><br /><br /></p><br />Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-74660545472315905122022-11-26T01:00:00.002-08:002022-11-26T01:00:00.164-08:00Aperture Matters Project Notes<p> Over this thanksgiving weekend, I've been able to work on the "Aperture Matters" project. Unfortunately, this is due to my partner being unwell and thus we were not able to celebrate the holiday with family.<br /><br />Quick recap of the project:</p><p>After the Golden State Star Party, I began to look at aerial lenses for large format as a way to complete the set for 4x5 film work. I'd picked up a couple of 508mm f5.6 lenses and was looking for the elusive next step. </p><p>I found that lens in Stockton for a decent price and got it sent to me. I knew it was a monster before I received it and when I finally had it in my hands, I also knew that it would require much more than just mounting a lens in a board and popping it onto the Horseman 4x5.</p><p> </p><div class="separator" style="clear: both; text-align: center;"><a href="https://live.staticflickr.com/65535/52234171756_b9ed067db3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="500" data-original-width="375" height="500" src="https://live.staticflickr.com/65535/52234171756_b9ed067db3.jpg" width="375" /></a><div class="separator" style="clear: both; text-align: center;"><a href="https://live.staticflickr.com/65535/52234445769_89a3d880b7.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="500" data-original-width="375" height="500" src="https://live.staticflickr.com/65535/52234445769_89a3d880b7.jpg" width="375" /></a></div><br /></div><br /><p></p><p><span></span></p><a name='more'></a> <p></p><p>The project required a few steps:</p><ol style="text-align: left;"><li>How to mount this lens properly? <br />It featured a nifty flange but I did not see a way that I was comfortable using that feature with my poor fabrication skills. The exterior of the lens is very close to the size of the Parallax rings that were made for the 127mm Maksutov Cassegrain, so I tested a trial fit. It was close enough to warrant having Parallax make a custom set. <br /></li><li>How to hold the ground glass and project an image onto film? <br />As I'd learned from the Horseman camera, I knew that having a strong rail was crucial to the rigidity of the system. I considered using bits from a set and ordered the items, but was never happy with the availability of short-length rails. <br />Also, I quickly found out that the Horseman bellows do not fit over the back of the lens, so I had to consider other brands. I researched and found that the Toyo G style bellows were a good match. Because of this requirement, I went with the Toyo system. Luckily, they have modular rails that were perfect for the small length needed.</li></ol><p>With these requirements in place, I was able to continue the parts list.</p><p>The 24 inch Losmandy plate is the longest on the market. Advantage is that it has a mess of holes already drilled.</p><p>Toyo rail tripod mount source and received. This is the part that would adapt the round rail to the Losmandy plate.<br /></p><p>Toyo rear standard sourced and received. This included the critical focus bits! The movements are still geared, so there is precise control.<br /></p><p>Toyo bellows support sourced (ebay) as the part to hold the front of the bellows up near the lens. This was going to be taken apart as I only needed the frame. My initial source failed to send the parts to me so I got it from another place. <br /></p><p>Toyo long bellows sourced and received (ebay). During a trial fit, I found that additional material would need to be ground from the inside of the bellows frame to drop over the back of the lens. A dremel tool and patient cutting was the solution. <br /></p><p>Toyo rotating spring back sourced and received (ebay). At the time, it was the only complete ground glass back I could find. The rotating function is nice but it does add more depth from the standard to the film plane. This makes the plan of using another guide camera for focusing need additional depth.</p><p>Toyo lens board sourced and received (ebay). The additional depth required for the digital camera focus means that I can't just mount a Lodestar in the hole like the Horseman project. Instead, I'll need more flexibility.</p><p>2 inch eyepiece adapter sourced and received from Agena Astro. This will fit into a 2 inch hole that will be cut in the lens board. I thought that I could drill the hole myself with a 2 inch hole saw, but that required hands of steel and I've opted to give the task to Tony to put on his lathe. </p><p>Because of the increased height of the Toyo film plane, the center of the lens also needed to be elevated. This presented a problem of rigidity. Parallax was not able to make rings that had the additional height built into their shape. I opted to get rectangular aluminum tube. 4 inch by 6 inch rectangular tube with 1/4 inch thick walls of 6061 aluminum were sourced from MetalsDepot.com and received. I felt that these risers would be up to the task of holding the system at the odd angles required for astrophotography. <br /></p><p>Putting all the parts together required hardware. Olander specializes in all the fasteners I could ever want, so I got them at work. 😀<br /></p><p>All these bits and parts arrived during August 2022, just prior to my travel to NC to help my sisters care for my father during his final months.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://live.staticflickr.com/65535/52386744347_25c5329633_z.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="521" data-original-width="640" height="521" src="https://live.staticflickr.com/65535/52386744347_25c5329633_z.jpg" width="640" /></a></div><br /> <p></p><p>Fast forward to November 24. After re-assembling the G11, I was ready for another project. I decided to drill the risers. In order to do this, I needed to mark the holes, which meant putting the bits together.</p><p>Here I have placed the lens on the rings and onto the risers. I'd hoped to have some space between the two aluminum boxes. In the end, no space was needed. In retrospect, I could have used a single, longer box and saved some drilling and the expense of getting the cut pieces.</p><div class="separator" style="clear: both; text-align: center;"><a href="https://live.staticflickr.com/65535/52521563444_d3c065dfd3_z.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="640" data-original-width="480" height="640" src="https://live.staticflickr.com/65535/52521563444_d3c065dfd3_z.jpg" width="480" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJ1isqkmJzp4Ilo1y2s6wWtCrnWiOXqMbC89StH5jp202OZ8biQv_gEnl0VFIsGdPXkyWoKVKTwVUEORd5dA1ytkN7aGmmxX3WoTC6CMTyTXcN3nA7ipVJjkXPZDRcs0-_6G5-ZigbDEup38PUWIMd_VGRXCtMbIdYNxYpXJofNOw_qgk4Y4mxuV6E/s4000/trial-fit_52520820432_o.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgJ1isqkmJzp4Ilo1y2s6wWtCrnWiOXqMbC89StH5jp202OZ8biQv_gEnl0VFIsGdPXkyWoKVKTwVUEORd5dA1ytkN7aGmmxX3WoTC6CMTyTXcN3nA7ipVJjkXPZDRcs0-_6G5-ZigbDEup38PUWIMd_VGRXCtMbIdYNxYpXJofNOw_qgk4Y4mxuV6E/s320/trial-fit_52520820432_o.jpg" width="240" /></a></div><br /><div class="separator" style="clear: both; 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margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgV05VHsldpi-iY0qFbXVMP4ozexp67ERIrfhAgwKuCYD-Rc0-7C4nHuwKVbbgW-nC4FjAk_jQ2RuFAXq2r6KBSqCQvgep24b0EbSHNu-iINNCpLkICp0s4mji8j51YRBUpVIUTeOYW1_M5j2YotEgZzNVQZ9pUsIxJcsmChAfJvkSXJDwDbXMYig2H/s320/hole-placement_52521723996_o.jpg" width="240" /></a></div><br /><br /><p><br /></p><p>The above sequence shows the steps I went through to drill and mount the risers and then the rings. I broke one drill bit with a pilot hole with being too hasty. Also, my marking of the holes left a little too much error on two spots I had to drill out a larger hole for each. I broke a small file trying to make the hole oblong. 😒</p><p>Mounting the rings was easier as the holes were in a line and didn't require much thought.</p><p>Hardware used was 1/4-20 hex head screws, a mix of 1/2 inch to 1 inch long. The hex head allowed me to use a small ratchet wrench in the tight space. The slightly larger than required holes for the rings will allow small movement of the lens to line it up properly.</p><p>Putting the rear standard on the rail was a breeze compared with the lens.</p><p>Breaking down the bellows support, I was able to slide it under the lens and put it on a temporary fit with some adhesive. </p><p>At the end of the day, the project had come along very well!</p><p><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizRmR-oEjEqoZFjO5jyVfn9CFhFWVActtmRkCdHsuCn0hFUAQRMHYs9Ja4WHgLf2ALVac8UFbeUepfyMu1TDYo72L0SNLUN7zzQU9wmGEmjhlBBIPRj13ROn8OrZpN8DXdu8RWK4QgInkIRxL3NJOPu8S4TOPXlrMOxJpbAiGExMPhWuy1ha4mvz9I/s4000/end-of-day_52521308987_o.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3000" data-original-width="4000" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEizRmR-oEjEqoZFjO5jyVfn9CFhFWVActtmRkCdHsuCn0hFUAQRMHYs9Ja4WHgLf2ALVac8UFbeUepfyMu1TDYo72L0SNLUN7zzQU9wmGEmjhlBBIPRj13ROn8OrZpN8DXdu8RWK4QgInkIRxL3NJOPu8S4TOPXlrMOxJpbAiGExMPhWuy1ha4mvz9I/s320/end-of-day_52521308987_o.jpg" width="320" /></a></p><p>Next day, I fitted the bellows. It was a tight squeeze underneath the lens. I found that if the rings were raised the thickness of just one washer, there would be enough room for the bellows support frame. This was done before using two-part epoxy to fix the frame to the rings.</p><p>Putting the whole system on the GM8, I was a little worried about the total weight. I put a second 21 lbs weight on the bar and found that the rig would balance with the weights only half the distance down the bar. This was a nice sign that the whole thing would work well. Also, the front-to-rear balance is at a reasonable point.</p><p>I noticed the long bellows sagging and this will require some support to prevent them from moving during a long exposure. I will make something eventually, probably a piece of aluminum sheet that can be folded to the right height.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjqnpYKKIb3hMu0WYMmT3h6DQrgALhb5cUdySjmu4e8ML9p5bbMR4SZRP8mJzabIlDoS2MQcLr9RMz9Vl6-1dyiWNfqPhU6ZssUpqAi1tvw7PFqIppDBZp0BtHYDUQalP8Go9fepEM7Wm2pxYBiQof3i41shEUkqW8bXgDVJhhZ07EgJhGgVs8l1v6O/s4000/view-camera-view_52522659242_o.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjqnpYKKIb3hMu0WYMmT3h6DQrgALhb5cUdySjmu4e8ML9p5bbMR4SZRP8mJzabIlDoS2MQcLr9RMz9Vl6-1dyiWNfqPhU6ZssUpqAi1tvw7PFqIppDBZp0BtHYDUQalP8Go9fepEM7Wm2pxYBiQof3i41shEUkqW8bXgDVJhhZ07EgJhGgVs8l1v6O/s320/view-camera-view_52522659242_o.jpg" width="240" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcy8vOD4Rr1bYeygxhiIl54g8wmOs-A6K1qxRK6R8Lnqvja6U2IQxs3l1bo-3XlbCcdF98XmpNuc_m_j5sS9Nz-ZVZm_zGql57j9WOVvivHdMeyIuFvTLx5u4rGaIFkdBJ6jWELj5XcuvYyEtFHXILHkDngmX2lBxAUXhWbd74Z0In6HE7yuuGiiZq/s4000/view-camera-view_52523125446_o.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3000" data-original-width="4000" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcy8vOD4Rr1bYeygxhiIl54g8wmOs-A6K1qxRK6R8Lnqvja6U2IQxs3l1bo-3XlbCcdF98XmpNuc_m_j5sS9Nz-ZVZm_zGql57j9WOVvivHdMeyIuFvTLx5u4rGaIFkdBJ6jWELj5XcuvYyEtFHXILHkDngmX2lBxAUXhWbd74Z0In6HE7yuuGiiZq/s320/view-camera-view_52523125446_o.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLFg7ELQX3DKOdvSuk7GIox3KfFMqxlGYzKuh9ygMVmurZwTLv5iAQFAJHGJ2dYx5SIj2AtXTRgnSXM9m2fWnwGPFQIa8KaGqzNs7UAb6Q2s2khqCauIBMSocgLcryvilq5AbAv7aIuE8GB9QXKNQWk251yOh7mmCa3l97HO6XjBxYRLL9UJfPXyj5/s4000/view-camera-view_52523403954_o.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="3000" data-original-width="4000" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiLFg7ELQX3DKOdvSuk7GIox3KfFMqxlGYzKuh9ygMVmurZwTLv5iAQFAJHGJ2dYx5SIj2AtXTRgnSXM9m2fWnwGPFQIa8KaGqzNs7UAb6Q2s2khqCauIBMSocgLcryvilq5AbAv7aIuE8GB9QXKNQWk251yOh7mmCa3l97HO6XjBxYRLL9UJfPXyj5/s320/view-camera-view_52523403954_o.jpg" width="320" /></a></div><br /> <p></p><p>There were few clouds in the sky. I found a little bit of wispy cirrus and was satisfied that the infinity point could be reached. The Toyo focus system worked like a breeze!</p><p>A few moments later, I was treated to the sight of two jets crossing the sky at height. This was the perfect opportunity to get a short video from the ground glass. I am pleased to see that there was no visible purple fringe. The edge of the ground glass got a little blurry, there are a lot of things yet to do to improve the image.</p><p></p><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="416" src="https://www.youtube.com/embed/sbG7thpI9k0" width="500" youtube-src-id="sbG7thpI9k0"></iframe></div><br /> <p></p><p>I cleaned the optics and then opened the lens and cleaned the insides. It's amazing how large this lens is. I can fit my entire hand through the center to clean the inside of the rear cell. During this operation, I flocked the exposed brass surface. </p><div class="separator" style="clear: both; text-align: center;"><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUzX5D9_vu29ls4xiVU7ZrS8hXSB_6rfxWInQ5-woNSl_C-GblGssiMIRDDGxONbs3PjfbJEcHL8APzYI3LYX1B-PozUthpEpt7_JxGGhd2ajPC-KKdJDD7PEPUEB8OlqlPfN3ffnq-wfLWVaevP1ug1JIK-6hELAfKdZ-abNz2oz0r81rLeYe0RJT/s4000/flocked_52523317321_o.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiUzX5D9_vu29ls4xiVU7ZrS8hXSB_6rfxWInQ5-woNSl_C-GblGssiMIRDDGxONbs3PjfbJEcHL8APzYI3LYX1B-PozUthpEpt7_JxGGhd2ajPC-KKdJDD7PEPUEB8OlqlPfN3ffnq-wfLWVaevP1ug1JIK-6hELAfKdZ-abNz2oz0r81rLeYe0RJT/s320/flocked_52523317321_o.jpg" width="240" /></a></div><br /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjOLcMgsfVutOvjo8fPcUe7CgYIp5FpzJ6wuk9-9xTm6BOvkThhu53yAI_iH1adIaVhVwTmeDFrU9zlKluBk-dgGVW_FKain86XCoWyXfmLnf_nQcLsoTtiZZbcNGTMXr4ym-k2aK53Nm7AHuFLKtszBkPhd-DDmOBEtt6w5SVqRYeNDVvDw7itv95K/s4000/bright-brass_52523437849_o.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="4000" data-original-width="3000" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjOLcMgsfVutOvjo8fPcUe7CgYIp5FpzJ6wuk9-9xTm6BOvkThhu53yAI_iH1adIaVhVwTmeDFrU9zlKluBk-dgGVW_FKain86XCoWyXfmLnf_nQcLsoTtiZZbcNGTMXr4ym-k2aK53Nm7AHuFLKtszBkPhd-DDmOBEtt6w5SVqRYeNDVvDw7itv95K/s320/bright-brass_52523437849_o.jpg" width="240" /></a></div><p><br /></p><p>To do:</p><p>Project an image circle at infinity (hopefully without bellows) to properly see the size of the circle. This SHOULD allow me to center the circle on the ground glass by moving the rings as noted above. I understand that these aerial lenses were built to work on 9 inch roll film, so there should be a lot of field to use. <br /></p><p>Once the epoxy cures at 24 hours, I'll be able to figure out something to block the last of the light coming around the lens body and the bellows frame. Quick solution is to drape a cloth over it. I will eventually cut some aluminum sheet to cover the gaps. Flocking and felt should work well to block any light gaps.</p><p>There is no shutter on this lens, so I'll need to make a lens cover. At the moment, I could use a pie plate or knit cap as a shutter. Something light like this will work for the astro shots. I never expect to use this setup for anything other than the task, so having a proper shutter is not needed. I'm looking at something to cover the front element for protection. I may use an aluminum cake tin with felting.</p><p>I may want to do some preventative bellows patching on some of the worn seams. Alternately, I could order some brand new bellows from e-Tone. Patch solution from Bostick and Sullivan requires 48 hours to properly cure. Will be an easy step to do during a full moon.</p><p>The digital focus device requires the 2 inch hole in the lens board. Will also require a Lodestar to mount. I currently only have one color Lodestar, so I picked up another black and white from Astromart.<br /></p><p><br /></p><br />Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-64112509121530460832022-11-25T17:53:00.000-08:002022-11-25T17:53:04.538-08:00Not quite first light...<p> </p><div class="separator" style="clear: both; text-align: center;"><iframe allowfullscreen="" class="BLOG_video_class" height="413" src="https://www.youtube.com/embed/sbG7thpI9k0" width="497" youtube-src-id="sbG7thpI9k0"></iframe></div><p></p><p>The big lens looking at the sky, airplane shows decent quality across the field of view.<br /></p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-56796776942664284632022-11-24T20:54:00.000-08:002022-11-24T20:54:00.844-08:00G11 refurbishment<p> Getting back to the second hand G11, I finally was able to complete the re-assembly.</p><p>Taking time to only grease the parts that required it, removing grease residue with acetone, and careful re-assembly, I was able to put the mount back together over a couple of nights.</p><p>Because there is no light after work these days, I have to make do with a lamp in the shed to see the task. Easy enough, I sit on the camp chair at a convenient height to work on the mount, and can fiddle and tweak.</p><p>Once I had the mount together, I was able to test the free movement of the axes before putting the goto assembly on it.</p><p><a data-flickr-embed="true" href="https://www.flickr.com/photos/smigol/52520232765/in/datetaken/" title="Testing the axes for smooth motion"><img alt="Testing the axes for smooth motion" height="1080" src="https://live.staticflickr.com/31337/52520232765_de13527e11_k.jpg" width="1920" /></a><script async="" charset="utf-8" src="//embedr.flickr.com/assets/client-code.js"></script></p><p>The goto won't be fully complete until I receive the one piece worm blocks from Losmandy. Placed the order last week for the two parts and I expect they will arrive sometime in December. In the meantime, I tested with the older multiple part worm blocks. These old worms appear to be the stock and not the brass high precision ones. I ordered the Losmandy complete blocks so these will be upgraded as well.</p><p>Lesson learned from the gearbox swap a few years ago - leave the gear box covers loose to inspect and adjust the Oldham coupler alignment. The more these couplers are off center, the more noise and periodic error they introduce. Running the motors in "Center" speed is just enough to observe any offset.</p><p>I am satisfied with the rebuild until I get it under the skies with a proper load on it. I don't think that will happen during this new moon cycle, but it could.<br /></p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-6014591348773218182022-11-07T18:55:00.001-08:002022-11-07T18:55:28.779-08:00Got inside the new-to-me G11<p> I finally had the chance this afternoon to do some work on that second-hand g11 that I picked up at GSSP.</p><p><br />Whoever had this mount earlier did a horrible disservice to themselves.<br /><br />As far as I can tell, the mount was disassembled prior to use and all the original Losmandy grease was replaced with automotive wheel bearing grease. It had that unmistakable reek of sulfur. Sticky mess, too. Somehow they thought proper practice was to pack the worm gear with the stuff. I can remember packing wheel bearings on the VW beetle and this is probably what the user must have considered appropriate.<br /><br />In heat and cold cycles the grease had migrated to the nylon pads. This meant that there was terrible "push to" function. To combat this, the user had tightened the RA and DEC axes impressively, making it a real chore to break them loose. The grease went far beyond the pads. It worked its way around the axes, underneath and between practically all the moving surfaces. This sticky grease was also slathered on the pin bearings inside and on the RA and DEC shafts. It was embedded into the worm gear assembly, making these normally sealed bearings gummed up and unable to move.</p><p></p><p>If the user had powered this up during a warm summer evening, it would have tracked well so long as it was locked down. Unfortunately, once the mount started to cool off, the grease would have become stiff and likely the whole mount would seize. I would not be the least bit surprised if the original motors had cooked.</p><p></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQghv--y96oVksz5BTSDaYkof4_afjWsGDYG8lfCvcYSfs5jNyJchYvqJejdQbKK4r1wkDC4cpGhMDFKmRiBzDZOLn4B9Eu31A64znPNXbi9E1Q34WyI6lKt_Q9ORXievnclfzndxuBFYKKZYgVb5l_sF7_U4BW8t7IJl9xaM9-dXr5leS5RLKfanK/s800/52485405469_225daffcd0_c.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="600" data-original-width="800" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiQghv--y96oVksz5BTSDaYkof4_afjWsGDYG8lfCvcYSfs5jNyJchYvqJejdQbKK4r1wkDC4cpGhMDFKmRiBzDZOLn4B9Eu31A64znPNXbi9E1Q34WyI6lKt_Q9ORXievnclfzndxuBFYKKZYgVb5l_sF7_U4BW8t7IJl9xaM9-dXr5leS5RLKfanK/s320/52485405469_225daffcd0_c.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHQvBv5lUuhr2QZujo0T8kKQWvo6HYltP_r1hvk5aHE7mYQAhbkNCUAcZa0k0CJJDXB6_K8Kq8JYPEPgIc6fhqj9A7OZdnv1_uL7L413AOVC1a80Mt7mplGefanboL0XyJ60-T9b_3RKfGmEydGswli3VT10rn5qpGYTn-wervQHij9xS9TgHoHXGR/s800/52485681253_94fb94f2a1_c.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="600" data-original-width="800" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhHQvBv5lUuhr2QZujo0T8kKQWvo6HYltP_r1hvk5aHE7mYQAhbkNCUAcZa0k0CJJDXB6_K8Kq8JYPEPgIc6fhqj9A7OZdnv1_uL7L413AOVC1a80Mt7mplGefanboL0XyJ60-T9b_3RKfGmEydGswli3VT10rn5qpGYTn-wervQHij9xS9TgHoHXGR/s320/52485681253_94fb94f2a1_c.jpg" width="320" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7U8_jBPAJa4f_VZ0mhEc8k0Ul2MgsWGEtfPWH_Ns2Pr4S_Jb5dSdZu7D87X1_J6Yxp8-Xjr0I5YOqeZ9Fjfw0XSFEB8EIgf9lk4K7FCcvpoueROaxEF6nUU5EXAwSxEHhmEMpcfNf9qSC7p4Fll-fsdjwSNNJvTA2l792F1pajEZ3vGbfvhOrBUTL/s800/52485681263_3ac2cdc457_c.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="600" data-original-width="800" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj7U8_jBPAJa4f_VZ0mhEc8k0Ul2MgsWGEtfPWH_Ns2Pr4S_Jb5dSdZu7D87X1_J6Yxp8-Xjr0I5YOqeZ9Fjfw0XSFEB8EIgf9lk4K7FCcvpoueROaxEF6nUU5EXAwSxEHhmEMpcfNf9qSC7p4Fll-fsdjwSNNJvTA2l792F1pajEZ3vGbfvhOrBUTL/s320/52485681263_3ac2cdc457_c.jpg" width="320" /></a></div><br /> <p></p><p></p><p>As it was a cool day, not reaching much into the 60s, the mount was already stiff. I knew something was up when I wondered where was the loose, floppy problem that I'd noticed at GSSP.</p><p></p><p>I opened it up to start the conversion to go-to and that's when I found the worm gear packed with the grease.<br /><br />I broke the whole thing down, dumped all the bits into a basin and sprayed the whole thing with engine degreaser. The grunge was slow to break down. Had to use several shop towels to scrub out the goopy mess. <br /><br />During this time I found that the ring gear had not been used enough to wear the anodizing! This is what makes me think that the mount has never been really used except to disassemble and repack.</p><p>All the parts are now sitting in the shed on newspaper, waiting for me to get the chance to return to them. I might have to re-degrease them with new chemicals and fresh shop towels.</p><p>Once this is done, I can put the superlube on it all and start the process of re-assembly.<br /></p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-28997885593947161002022-07-22T13:31:00.004-07:002022-11-18T20:37:36.281-08:00Aperture Matters<div style="text-align: left;"><br />My fascination with aerial lenses has landed me with another large piece of glass.<br /><br />This latest aquisition came from Stockton, CA, and is the venerable 900mm f8 lens. This particular example does not have aperture blades or a shutter so it will need to be used wide open. I will need to make a lens cap for it to function as a shutter. From what I can gather, it should be able to project a usable field up to 8x10, possibly more. I won't have the ability to use all of that since I have the 4x5.<br /><br />To use this large piece of glass, I'll take advantage of the flange to mount it to a frame made of angle iron. I'm planning to modify a Horseman 4x5 front standard to mount it. I have one on order for parts for just this purpose. <br /><br />Given what needs to be done, it's unlikely that this will see first light before the end of the year. </div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhV3bG2o7-8_cwqqTO2E2N_CsJsXyvwtScNkTB0L6TqJjyfabQc1bVaArr4Qw6woQQyIfJMwgl4BsSTevWgj5SqOz34-tWJUEonUlC6AlIc7IH3M1oqhsrWwz8wVpxItarT0SkN2nCnI7KeDII8ktokm3eM96lhedNX9tfe3Rqzh_8XxvYtrNJCfKNm/s800/52234171756_b9ed067db3_c.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="800" data-original-width="600" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhV3bG2o7-8_cwqqTO2E2N_CsJsXyvwtScNkTB0L6TqJjyfabQc1bVaArr4Qw6woQQyIfJMwgl4BsSTevWgj5SqOz34-tWJUEonUlC6AlIc7IH3M1oqhsrWwz8wVpxItarT0SkN2nCnI7KeDII8ktokm3eM96lhedNX9tfe3Rqzh_8XxvYtrNJCfKNm/w300-h400/52234171756_b9ed067db3_c.jpg" width="300" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcDMF1ZNVdShcPryMo19ahOToiXK2s8f45ay7pZGIXeqjF02bMH2S2PoHZwpq1m0otojOjkzCd3zGJOeFJZ2o8Khc7y9H3Rgn0v91wwfB7gHS-JS0ZrG-P90XPPJWkAkgJ67KOdIRrmKYZTan-Dgr0cN4i3cB5WNSxmN5sb6ubCyhp4Jo8ZiIwEEUT/s800/52234179273_c3b10e44fa_c.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="800" data-original-width="600" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcDMF1ZNVdShcPryMo19ahOToiXK2s8f45ay7pZGIXeqjF02bMH2S2PoHZwpq1m0otojOjkzCd3zGJOeFJZ2o8Khc7y9H3Rgn0v91wwfB7gHS-JS0ZrG-P90XPPJWkAkgJ67KOdIRrmKYZTan-Dgr0cN4i3cB5WNSxmN5sb6ubCyhp4Jo8ZiIwEEUT/w300-h400/52234179273_c3b10e44fa_c.jpg" width="300" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoHLY08TYCAI_EHEVlxY9cWxxvtPHXlf8ISCJIjoYP_opsutuuK1JIAmU6vYDZ2puzIaHBLPVSUXnRfABOBaZLJHE64A4v_txTewxgYJ_O_SVcULhoFLwgcozuslmuGzTBL0SB4ZmbEmYqMgHebTO9dcaOHXy_ola2xj2MiwMj799lOXPD4SCcHlTC/s800/52234445769_89a3d880b7_c.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="800" data-original-width="600" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoHLY08TYCAI_EHEVlxY9cWxxvtPHXlf8ISCJIjoYP_opsutuuK1JIAmU6vYDZ2puzIaHBLPVSUXnRfABOBaZLJHE64A4v_txTewxgYJ_O_SVcULhoFLwgcozuslmuGzTBL0SB4ZmbEmYqMgHebTO9dcaOHXy_ola2xj2MiwMj799lOXPD4SCcHlTC/w300-h400/52234445769_89a3d880b7_c.jpg" width="300" /></a></div><br /><div style="text-align: left;"><br /></div><p> Followup: The Horseman 4x5 bellows do not fit over the back of this lens. Thus, I'm going to use the Toyo 160mm size bellows. These will drop over the lens and allow the use of a rear standard for focusing and film holding. I've got the bits on order to fabricate half of a camera.</p><p>Mounting the lens is going to be interesting. The flange that is already on the lens is a wonderful thing, but I'm opting to re-use the rings from the Mak project. These are 143mm rings that will need some shimming of the lens to properly grab the tube. Tony has a metal roller and can help bend some shims to fit the proper size. Just need to measure the thickness needed. I think that 2mm will do the trick.</p><p>That flange may end up being a place where I can put some handles. <br /></p><p>Lastly, the center of the lens once mounted will need to line up with the center of the ground glass. The Toyo 45G will have a center that will be about 100 mm higher than the lens. Once I get the rear standard in my hands I will be able to properly measure it. The rings will need to be lifted by using some square tube stock.<br /></p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-25243841685825913192022-07-20T22:02:00.002-07:002022-07-20T22:02:38.844-07:00Focusing Thought Experiments<div style="text-align: left;"><span id="docs-internal-guid-0d24937c-7fff-e44a-f6e8-b8addde9f263"><p dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"><span style="font-family: Arial; font-size: 11pt; font-variant-east-asian: normal; font-variant-numeric: normal; vertical-align: baseline; white-space: pre-wrap;">The film we use doesn't see the unfocused light, so it's not a big issue (as far as I know).</span></p><br /><p dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"><span style="font-family: Arial; font-size: 11pt; font-variant-east-asian: normal; font-variant-numeric: normal; vertical-align: baseline; white-space: pre-wrap;">I do know that the lodestar autoguider that I use in my bahtinov mask focus confirmation tool sees the near IR. Thus, I'm considering filtering the light either at the sensor of the digital camera, behind the lens, or in front of the lens. Each option presents its own challenge.</span></p><br /><p dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"><span style="font-family: Arial; font-size: 11pt; font-variant-east-asian: normal; font-variant-numeric: normal; vertical-align: baseline; white-space: pre-wrap;">I found that for the 300 mm lens, the focus pattern didn't seem to have too many problems, but when looking at the 400 mm lens, the star image is sloppy and I can't get a consistent pattern. I think that the issue is the NIR. I ended up using no mask for the 400mm images and focused to get the smallest stars when using the digital sensor. This may have been the biggest issue after sag.</span></p><br /><p dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"><span style="font-family: Arial; font-size: 11pt; font-variant-east-asian: normal; font-variant-numeric: normal; vertical-align: baseline; white-space: pre-wrap;">Before the star party, I was doing testing in the back yard where I'd take a picture of a measuring tape at close focus. I'd develop the film and then set the distance of the lodestar to match the focus spot exhibited on the film. It required a few days to get it right. I also was swapping the ground glass back and forth with using shims. In the end, I found that no shims were required and a ground glass with no fresnel gave the best view.</span></p><br /><p dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"><span style="font-family: Arial; font-size: 11pt; font-variant-east-asian: normal; font-variant-numeric: normal; vertical-align: baseline; white-space: pre-wrap;">The testing scene was lit with LED lights which may not have had a NIR component. Plus, I was testing with the 300mm lens.</span></p><br /><p dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"><span style="font-family: Arial; font-size: 11pt; font-variant-east-asian: normal; font-variant-numeric: normal; vertical-align: baseline; white-space: pre-wrap;">The difficulty about introducing an IR filter to the light path has these problems:</span></p><br /><p dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"><span style="font-family: Arial; font-size: 11pt; font-variant-east-asian: normal; font-variant-numeric: normal; vertical-align: baseline; white-space: pre-wrap;">1. At the sensor for the autoguider: Easy to do, cheap option ($50 for a screw in filter). Could GLUE a cheap colored filter in place - yellow would be ideal as it would block blue and should block IR. Works for all the lenses to be used, adds protection for the sensor when it's not in use. Disadvantage is that it requires refocusing the system because the sensor and film plane will no longer match. Requires another couple of pictures of a ruler (again). There may not be enough adjustment room left on the guider body to accomodate an additional 1mm of distance.</span></p><br /><p dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"><span style="font-family: Arial; font-size: 11pt; font-variant-east-asian: normal; font-variant-numeric: normal; vertical-align: baseline; white-space: pre-wrap;">2. Behind the lens with a screw in filter. Expensive but I should have the filter already - just have to find it. The backfocus adjustment issue should be mitigated because both the film and the digital sensor will be offset the same amount. Disadvantage is that different sizes of filters would be required for each lens set. </span></p><br /><p dir="ltr" style="line-height: 1.38; margin-bottom: 0pt; margin-top: 0pt;"><span style="font-family: Arial; font-size: 11pt; font-variant-east-asian: normal; font-variant-numeric: normal; vertical-align: baseline; white-space: pre-wrap;">3. In front of the lens with a screw in filter or gel or square filter. Expensive as these will be even larger. Gels don't block IR, either. I have fabricated a 100mm square filter holder which might work if I can confirm that LEE filters block IR. I've sent a note off to LEE for information. </span></p><div><span style="font-family: Arial; font-size: 11pt; font-variant-east-asian: normal; font-variant-numeric: normal; vertical-align: baseline; white-space: pre-wrap;"><br /></span></div></span></div>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-10608907835910975902022-07-15T15:29:00.004-07:002022-11-18T20:37:48.520-08:00A Big Lens<p><br /></p><p>During the GSSP 2022, there was an opportunity to get an interesting lens that may be ideal for astrophotography.<br /></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhI4rUWwestSo8b1u-I9K1x81-PHdMIOdza-8Dww3krcFv1qjkmKajvW5zrtqLZCjcPAkoNm-Gm2-CbzDGkTP0YrhMUetpFQb5H_GUDg_pUHpNTmnrIQjYKFRclhFppolfYD0VcIrNiRdCGqyqz8AY-WpGNYGdtW1jH4qhY7yedjYL4y7N6A85FlZoM/s800/52197612262_94e628cecb_c.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="800" data-original-width="600" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhI4rUWwestSo8b1u-I9K1x81-PHdMIOdza-8Dww3krcFv1qjkmKajvW5zrtqLZCjcPAkoNm-Gm2-CbzDGkTP0YrhMUetpFQb5H_GUDg_pUHpNTmnrIQjYKFRclhFppolfYD0VcIrNiRdCGqyqz8AY-WpGNYGdtW1jH4qhY7yedjYL4y7N6A85FlZoM/s320/52197612262_94e628cecb_c.jpg" width="240" /></a></div><p><br /><br />The Bausch and Lomb 508mm F5.6 lens was designed for use in aerial photography. There are aperture blades, but no shutter.<br />The version that I picked up at GSSP also has no coatings and has some separation in the rear element.<br /><br />Within a week after returning from the star party, I'd asked my co-worker to cut a hole in a Luland board to hold the lens. Tony was able to make the cut and return the board to me by Friday. Working at Olander has the benefits of being able to select the perfect hardware for the job. 10-32 x 5/8 long screws were the ideal length and we had blackened zinc in stock. </p><p><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEGaNXCiAAn1_sjtQzhitgasJCOvt_pjovHFbkfAssANwgG4nQNQtW_AZ-S7lEGPkO4E7rv--vT_o9MLePGXW5t3u9ZWZCDrwKgVrnpBQqi1uSKQHWv4WcxecRef8kWEUNffINoSJmq-dLbkotj-S4JTLEQehBgglDRn6R1a8x635n0sgTk7pv2yxs/s800/52203955335_1369a355f4_c.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="800" data-original-width="600" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjEGaNXCiAAn1_sjtQzhitgasJCOvt_pjovHFbkfAssANwgG4nQNQtW_AZ-S7lEGPkO4E7rv--vT_o9MLePGXW5t3u9ZWZCDrwKgVrnpBQqi1uSKQHWv4WcxecRef8kWEUNffINoSJmq-dLbkotj-S4JTLEQehBgglDRn6R1a8x635n0sgTk7pv2yxs/s320/52203955335_1369a355f4_c.jpg" width="240" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEillW9epfKZVVVig_vwbzmLSobO4T7iCj9LR2NUuHY7Q0MNEGOBrIMbsIJsag0GQMlxS1ak2x6I6SZO3nJdiJjuiFY6ru93DflPYxz4SG0HKsOtmUdKNZDkBJdiJTQYLBEmAenAhSKSm6VkXsmmkdOpqpCNaeiaYhxucbJndExbT1_SrhTT_OyqlO98/s800/52203719919_1881a35628_c.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="800" data-original-width="600" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEillW9epfKZVVVig_vwbzmLSobO4T7iCj9LR2NUuHY7Q0MNEGOBrIMbsIJsag0GQMlxS1ak2x6I6SZO3nJdiJjuiFY6ru93DflPYxz4SG0HKsOtmUdKNZDkBJdiJTQYLBEmAenAhSKSm6VkXsmmkdOpqpCNaeiaYhxucbJndExbT1_SrhTT_OyqlO98/s320/52203719919_1881a35628_c.jpg" width="240" /></a><br /><br />The lens looks crazy hanging off the front of the Horseman. I can see the sag in the standards from the weight. There will need to be some kind of lens support for this beast if I expect to use it for astrophotography.</p><p><br /></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisTqgm45FGFYQXRbBbu1u5tMbl4E3bdT_YNDMWnR2cOaCOUU8ou8tLqLCsOMb0SiSGPQJOqEyYkRMkx9a9B6iUU4K59uDxNTAveF1cygdu_Kn5wVfu5-py-xsfP_ih_AVX_CInENgMnhDiS-wmTr65r8ikXMeyclrz0ZlTQ1ulWp1e_QxHAZmwLj8l/s800/52203955440_ecf367626c_c.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="800" data-original-width="600" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisTqgm45FGFYQXRbBbu1u5tMbl4E3bdT_YNDMWnR2cOaCOUU8ou8tLqLCsOMb0SiSGPQJOqEyYkRMkx9a9B6iUU4K59uDxNTAveF1cygdu_Kn5wVfu5-py-xsfP_ih_AVX_CInENgMnhDiS-wmTr65r8ikXMeyclrz0ZlTQ1ulWp1e_QxHAZmwLj8l/s320/52203955440_ecf367626c_c.jpg" width="240" /></a></div><p><br />Was suprised that the standard 400mm rail has enough room for proper infinity focus. I tried viewing the daytime moon and it was easy to hit it. On the other extreme, even without changing the rail there's enough room to allow close focus of 15-20 feet. I'm sure that a longer rail the setup could be used at much shorter distances.<br /><br /></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixO4v1frme4y8ajZY8a-Nw3qdKrQh-AX7t4IcP3lzt5Z9PQZve-CwKRE3rvucy-AiZOfSWYJIfqnfzu8rPjt28Josgomx-6yqC6oHwMD2HmYZs5vF4YD4tffwP9WVZtBotq9NjQ1HnL6OJFwEe1QvQAJf1JRFfugtAACQ-1ZNF-r0Pu8NVdIFiy6OP/s800/52203450661_f576ddea34_c.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="600" data-original-width="800" height="240" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEixO4v1frme4y8ajZY8a-Nw3qdKrQh-AX7t4IcP3lzt5Z9PQZve-CwKRE3rvucy-AiZOfSWYJIfqnfzu8rPjt28Josgomx-6yqC6oHwMD2HmYZs5vF4YD4tffwP9WVZtBotq9NjQ1HnL6OJFwEe1QvQAJf1JRFfugtAACQ-1ZNF-r0Pu8NVdIFiy6OP/s320/52203450661_f576ddea34_c.jpg" width="320" /></a></div><p><br /><br />Shortly after returning from the star party, I was doing research on the 508mm lens and found a later version that had been modified with a shutter. Of course, I had to get this as well.<br /><br />Now is the challenge of trying to modify the modifications to put it on a 140mm board. Again, it's good to have co-workers that are skilled and have a lathe since cutting the 82mm hole requires more skill than I have.<br /><br />Lastly, I found that Luland makes a lens support. Of course, this is a perfectly timed offering since I needed to buy a few more supplies.<br /></p><br /><br /><br /><br /><br /><p></p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-41427343145850969382022-07-13T22:26:00.004-07:002022-07-13T22:26:28.615-07:00Two more E100 sheets from GSSP 2022<p> NGC 7000 region shot on Thursday night at GSSP 2022. <br /><br />Schneider 300mm lens at f5.6. 120 minute exposures. No filters. <br /><br />There's significant lens sag that's robbing decent focus. Hoping to fix this problem prior to the next star party.<br /><br /><br /><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBrdn1OYQQwg1AiLcNbf7WsLJqnwFwc3WGh1IB4UebVjgaIKHtFApp6_7Bc3Xf8k9TbIywMkvz183UHgD821rAoOI8f02gOwkdbNcGERcLrspl4cICGaH2UFkEDIxcgFsiLchWXu7WcsySWMwFs0SqdF-NBuzZzHG7-aMqFtznE-sViVf_YGN5y_Pb/s2048/52215424629_495281dec8_k.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="1630" data-original-width="2048" height="319" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhBrdn1OYQQwg1AiLcNbf7WsLJqnwFwc3WGh1IB4UebVjgaIKHtFApp6_7Bc3Xf8k9TbIywMkvz183UHgD821rAoOI8f02gOwkdbNcGERcLrspl4cICGaH2UFkEDIxcgFsiLchWXu7WcsySWMwFs0SqdF-NBuzZzHG7-aMqFtznE-sViVf_YGN5y_Pb/w400-h319/52215424629_495281dec8_k.jpg" width="400" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">https://flic.kr/p/2ny6GzT</td></tr></tbody></table><br /><table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto;"><tbody><tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjPeuMgtP8YJT4DnWVYMMiOsRtj2lGsOJwzCjrwFj5tshFi5geui88hFmzY1f8dL4u-yK8k5JKsxibiTz6T5iYFTaZOqKa9t41tKz_jgVFd0hFcklxG0aUEvz8D8eVSN6B5eU4ecjOchrKVPl3sDByn4SBXcLPov9tiiZtN-gzNjANcPUQmb6o2l_4k/s2048/52214143767_70175550fc_k.jpg" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" data-original-height="2048" data-original-width="1620" height="400" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjPeuMgtP8YJT4DnWVYMMiOsRtj2lGsOJwzCjrwFj5tshFi5geui88hFmzY1f8dL4u-yK8k5JKsxibiTz6T5iYFTaZOqKa9t41tKz_jgVFd0hFcklxG0aUEvz8D8eVSN6B5eU4ecjOchrKVPl3sDByn4SBXcLPov9tiiZtN-gzNjANcPUQmb6o2l_4k/w316-h400/52214143767_70175550fc_k.jpg" width="316" /></a></td></tr><tr><td class="tr-caption" style="text-align: center;">https://flic.kr/p/2nxZ8Q4</td></tr></tbody></table><br /></p>Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-56248018444105375052022-07-13T08:20:00.005-07:002022-07-13T14:01:53.481-07:00Cephus region on 4x5<p> Latest effort was 2 hours on Cephus on the 4x5 with a 400mm lens at f5.6.<br /><br />I'm pleased with the results. There are some errors and I look forward to refining the technique.<br /><br />Flickr link:<br />https://flic.kr/p/2nxNwwd<br /><br />Astrometry page:<br />https://nova.astrometry.net/user_images/6120044#annotated<br /><br /></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9rF3YVf93DnZ0_Vz_43J1CmAEOCmjg1a0lL4USzV4NaoPFoYKifZ4jwAkED0uv0nWgRkM8pGumkq2dMt19OuVZgRAnSgPn_jZ23lWXeMGHAYdVdO16xNfeKuYuM3Z37A9e0heM-eWKUXGP_a1Y6cQiXUJDgqp5oa2XVoAfvMtVloAwfUpyJo194BP/s1024/52212073872_dbd1d11444_b.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="815" data-original-width="1024" height="319" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9rF3YVf93DnZ0_Vz_43J1CmAEOCmjg1a0lL4USzV4NaoPFoYKifZ4jwAkED0uv0nWgRkM8pGumkq2dMt19OuVZgRAnSgPn_jZ23lWXeMGHAYdVdO16xNfeKuYuM3Z37A9e0heM-eWKUXGP_a1Y6cQiXUJDgqp5oa2XVoAfvMtVloAwfUpyJo194BP/w400-h319/52212073872_dbd1d11444_b.jpg" width="400" /></a></div><p><br /><br />I have been trying to see the dark nebula east of IC1396 for years. It finally has started showing up for me and I'm glad.<br /><br />Stuff to do:<br />Get better at focusing. The Lodestar is sensitive to the unfocused near IR that passes through this lens. Thus, the bahtinov mask image is not precise. I focused the 400 based on star size since that seemed to be the best indicator. I will put a UV/IR filter on the rear of the lens to see if that cleans up the signal. <br /><br /></p><br />Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0Adin, CA 96006, USA41.1349427 -120.97854212.824708863821158 -156.134792 69.445176536178849 -85.822292tag:blogger.com,1999:blog-8481375458403073225.post-71256240482781354492022-07-05T15:01:00.005-07:002022-07-05T15:03:16.582-07:00GSSP 2022 Report<p>Golden State Star Party 2022 is over!<br /><br />Quick summary of the event!<br /></p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBjpppOlQFOnCcpXTiXZnfCwu3u6QXeIbYjmQ8W-R4Y8k2rjS_FMTm2O89whyQCqQq4UD85WOm4r57EPdKeyI-LoGEOGVa_P2O1n0WmiXmRAntZT23TFXzZ1w6UGrPMj2wY27Opg20B4P_ljRzDbxlqOW-CJYS1LFfbFApeVSSkOtdHncIPaXX8ZtG/s800/52187689206_c83367541a_c.jpg" style="clear: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" data-original-height="800" data-original-width="600" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBjpppOlQFOnCcpXTiXZnfCwu3u6QXeIbYjmQ8W-R4Y8k2rjS_FMTm2O89whyQCqQq4UD85WOm4r57EPdKeyI-LoGEOGVa_P2O1n0WmiXmRAntZT23TFXzZ1w6UGrPMj2wY27Opg20B4P_ljRzDbxlqOW-CJYS1LFfbFApeVSSkOtdHncIPaXX8ZtG/s320/52187689206_c83367541a_c.jpg" width="240" /></a></div><p><br />Weather was great - temperatures were only in the upper 80s during the daytime. Strong breeze in the afternoon as usual. Cool nights, but not as cold as previous times, temperatures dropped to about 50.<br /><br />Wednesday night was clear and crisp - very little upper atmosphere haze and the milky way "crunchiness" extended down to 40 degrees altitude. Looking towards the south is always tempting at this dark site. The dark cloud distinction extended down to the south as well on this evening. I resisted shooting this location and only imaged as far down as 35 degrees.<br /><br />Much of the early night was lost to polar alignment - suprisingly difficult even with the polemaster! The G11 worked well and then the GM8 was a little more finicky since the adjustment screws are coarse. I chased PHD calibration issues for a while on the GM8 and finally settled on accepting the error message. I also had unexpected behaviour from the mount as it wanted to slew wildly during some park commands. After swapping out USB cables, I opted to remove the USB 3.0 hub that was in the power supply for the old style 2.0 hub I had in reserve. The first exposure of the night turned out to be a dud as I forgot to remove the dark slide. Oops! Only 1 image is likely to be any good that evening as I accidentally let the second image go well into dawn.<br /><br />While the 4x5 was imaging, I was able to put my attention to the SV4. I'd not done anything with this setup since 2018's LDN image. This showed as the QSI camera refused to start properly. Swapping out the cables and the 3.0 hub didn't improve the situation. I brought the camera into my tent so that I could easily bench test it without crouching at the telescope. No go, but I did get some interesting information that I used to post to the QSI Groups.io newsgroup. Eventually I sent a note to Atik support.<br /><br />Thursday night was not as crisp as the previous evening. Looking towards the south showed softness that extended well above 30 degrees and reminded me that going north to GSSP benefits shooting towards the north! <br /><br />Got two great exposures on the E100, 300mm at f5.6 (wide open - which I may regret). Both are 2 hours long. <br />Thursday's visit to the swap meet was serendipitous. Earlier in the day, I'd mentioned that my only "dream lens" for the 4x5 would have been the 600mm aero ektar. Strangely enough, there was a near equivalent on the table at the swap meet. For $75, I picked up the 508mm f5.6. There is some lens separation in the rear element. Not sure how this will effect the image. The seller is sending the yellow filter to go with the lens. This will be a good addition to the 500mm f7 I already have. Next step: ask Tony to cut out a large hole in one of the lens boards to fit this monster.<br /><br />Later in the day I went to the other vendor at the star party and found a used, push-to Losmdandy G11 mount. It needs some care to bring it back to proper function as the RA and DEC do not lock properly. I've done this kind of work before, so I'm excited to work on it. Best part is the pricing was hard to beat. Once I'd started the process of talking with the vendor, it was a slippery slope as I felt that I could maybe get the gear together to put one of Anthony's canon dslr on the SV4 since it was idle. Picked up a 60mm guide scope which actually is a pretty decent addition since it attaches to the Synta guider dovetail. In the end, I was unable to get it to work since there was no power source for the DSLR. <br /><br /><br />During the following daytime, Atik support got back to me asking for videos of the camera startup as the filter wheel and shutter wheel motors sometimes are dead when idle for long periods of time. Videos were shot and shared.<br /><br />Got a shower (finally) and got a few afternoon landscape pictures for a change. <br />Snapped some group photos of the nearby camp as it turned out to be the last night for all of us together. The sunset was dramatic and I got some frames on Ektar.<br /><br />Friday night had the same reduction of overhead sky. At 10 pm the circle of "crunchy" milky way was centered about 50 degrees altitude. Still large enough to image Aquila and northwards.<br /><br />I reloaded all the depleted film holders while an exposure was running. Surprisingly, the whole operation of sorting film into boxes and all that burned up an hour of time! <br /><br />After fiddling with film in the dark, I joined the rest of the crew over at the secondary dob camp for some night vision action. Phil Manela and a few others were using Willis' white phosphor camera on decent sized dobs. The ability to see faint nebulosity in real time is always great. This time the nifty feature was seeing the dark nebula between the North America nebula and the Pelican nebula. Being able to see the tendrils of darkness and texture in the nearby Cygnus Wall was superb. Somebody mentioned that it looked "ominous" - I remarked that the 3-D effect of the foreground object of the molecular cloud was plainly obvious to my eye.<br /><br />Standard two shots on E100 that night, ending at 3:15 am. Nice to get a good sleep afterwards.<br /><br />The final night gave poor expectations as Saturday afternoon had clouds moving into the area. Looking up, I could see what appeared to be high rain that was falling but not reaching the ground due to the arid conditions. Many people started leaving the site. I broke camp and packed the car, leaving just one tripod set up and preparing to sleep in the open on my cot. Looking towards the west, Shasta was covered by cumulonimbus clouds and it was expected that rain and lightning would reach the site eventually. Patience was rewarded as shortly after sunset the skies cleared. Not much imaging done as we all waited for the moon to set. I snapped a couple of "earthshine" images on the FPP Frankenstein film - one at 15 seconds and another at 60 seconds. The reduction of the crispness of the seeing continued the pattern as the overhead milky way looked soft. I settled into a taking a shot of the dark nebula in Aquila on Acros after 11 pm. Slept for 2 hours and woke to the flashes of light from the electric storm happening to the west. <br /><br />Taking this as a not-so-subtle hint to get packing, the last of the gear started coming apart at 1:30. Packed the car, leaving room for me to sleep behind the wheel. I got everything put away and pulled up at about 3 am and quickly fell asleep. Woke at a little after 5 am. No clouds in the sky, not a bit of rain had reached the site overnight. Had I been courageous, I could have captured a few more frames. Nevertheless, being packed and ready to leave at 7 am has its advantages and I was on the road early and home by 1 pm.<br /><br />Overall summary:<br />Great experience, would do it again! 5 stars! <br />Sucks not having the shower truck on site, but I learned how to embrace the funk and how to clean myself up with less than a liter of water.</p><br />Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0tag:blogger.com,1999:blog-8481375458403073225.post-49636396113119592802022-06-27T15:39:00.003-07:002022-06-28T10:47:13.943-07:00Preparations for the GSSP 2022<p> </p><p> I have done a lot of preparation to be ready for this event. Most of my efforts between Calstar 2021 and today have been on getting the most out of the existing equipment I have rather than trying new gear.<br /><br />Foremost, I've put quite a bit of time on analysis and understanding of the large format camera. I've built tools and done precision measurements and snapped lots of test shots to finally get to where I can say that focus is as good as I can make it.<br /></p><p></p><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjcY6Hez-nC-c9y5JOC0Rq08IeemrTmWEywSUYMXA7My4t_8AO1yFFZgfSsWwyO4MuRdBENWQ9DkK5aBXJ-xKZA-JKFNPpUCEoEwngF3J18jXKOiPveCpoXIRtqR8WfNktuSJzwYGK8ZjCzzBLQIYm8d3RHoilNmFaNhEpPbAViqVeNx7RUUT515SNp/s952/gssp%202022.png" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="643" data-original-width="952" height="216" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjcY6Hez-nC-c9y5JOC0Rq08IeemrTmWEywSUYMXA7My4t_8AO1yFFZgfSsWwyO4MuRdBENWQ9DkK5aBXJ-xKZA-JKFNPpUCEoEwngF3J18jXKOiPveCpoXIRtqR8WfNktuSJzwYGK8ZjCzzBLQIYm8d3RHoilNmFaNhEpPbAViqVeNx7RUUT515SNp/w320-h216/gssp%202022.png" title="Weather looks good!" width="320" /></a><p><br /><b>Issues up front: </b><br /><br />The ground glass as shipped with the camera was a plastic-sheet with integral fresnel screen. Great part, but it had scratches and a pretty coarse lens that introduced a lot of lines when trying to focus. Getting repeatable precise focus was a hit-or-miss event even with high magnification.<br /><br />I ordered a chinese-made ground glass made by e-tone. Visually, this is a great ground glass with a much finer fresnel lens. I really liked the grid lines and 6x7, 6x9, and 6x12 composition marks. However, the image is formed by a frosting layer that is plagued by dark spots. This robs the contrast needed for precise focus. Under a low mag loupe, the grain is invisble. This glass would be perfect for a field camera that used wide angle lenses. I may eventually get a second back to install this glass into for that purpose.<br /><br />In a last ditch effort to get a good solution, I wanted to try a focusing screen that was not made from plastic. I purchased a hand-made ground glass from a fellow in Washington state. His glass is hand-polished and is made from Schott glass. The product does not have a fresnel lens, as most of the work I do is with long lenses, vignette will not be a problem. Big advantage is that the lack of fresnel lines does not rob contrast. The fine grinding of the glass is evident as the view under 10x magnification readily shows detail that was invisible on the other ground glasses. <br /><br />Lastly, by doing all this work, I’ve set the focus on the loupe to properly account for the thickness of the glass. It was easy to focus on pencil marks on the matte surface. No longer distracted by the out of focus fresnel rings or subsurface texture in the plastic, my eyes easily see the image.<br /><br />Big thumbs up to the Horseman design as the Graflok back is easy to remove and put on a table for measurement, disassembly, and reassembly.<br /><br /><b>Lodestar assisted focusing:</b><br /><br />After Calstar, I made a device to give a "live view." Using a spare Lodestar guider and a lensboard with a Copal 1 hole, I mounted the autoguider in a parfocaling ring and then attempted to mount it at the proper distance to mimic film.<br /><br /> </p><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJqCwbZOwTwyUL_VWD1xKa6q8vERc7zpTH2lgsommfz5ArRyI67A3i0Ab5ada5fSs7i6BZk0HarV1XuCTXCu0Yz8wxN1cls3pVboYCfhBqydhK-2BA9AoncqjTs6F670WI05vrBKjA99e9JkjufrFq4K-bBj0AV1RXKFez0boQ5kWCnGqiPEQV5_tf/s800/51839864444_9ab51e0863_c.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="800" data-original-width="600" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJqCwbZOwTwyUL_VWD1xKa6q8vERc7zpTH2lgsommfz5ArRyI67A3i0Ab5ada5fSs7i6BZk0HarV1XuCTXCu0Yz8wxN1cls3pVboYCfhBqydhK-2BA9AoncqjTs6F670WI05vrBKjA99e9JkjufrFq4K-bBj0AV1RXKFez0boQ5kWCnGqiPEQV5_tf/s320/51839864444_9ab51e0863_c.jpg" width="240" /></a></div><br /><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBfPZ2pMmiDYVlEI0fWRgk46RAP0CuX_I-ncv-9NI457lj3tcGhs5pxJsOb2qmyCVcx4MPYNweoIZIGfhZVR8tGHDSpM4vpvSSu-Yfykko3l33SF4qPuGxY9rXDHaodLbgeNiMGUwxaUwlhW5MZhnwdPVOA_X8MK3r36Yk6u9RJcQ1ADNNaRHonH8O/s800/51838562552_28d3ed3759_c.jpg" style="margin-left: 1em; margin-right: 1em;"><img border="0" data-original-height="800" data-original-width="600" height="320" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjBfPZ2pMmiDYVlEI0fWRgk46RAP0CuX_I-ncv-9NI457lj3tcGhs5pxJsOb2qmyCVcx4MPYNweoIZIGfhZVR8tGHDSpM4vpvSSu-Yfykko3l33SF4qPuGxY9rXDHaodLbgeNiMGUwxaUwlhW5MZhnwdPVOA_X8MK3r36Yk6u9RJcQ1ADNNaRHonH8O/s320/51838562552_28d3ed3759_c.jpg" width="240" /></a></div><br /><br /><br />Through the fall of 2021, I would snap pictures of Orion, attempting to compare lens image flatness. Would use this live view tool to focus a bahtinov mask. To work with smaller lenses, I purchased smaller-sized masks. Over the months through October and November, I would run up to Montebello, take some pictures, then develop over the coming days. This feedback loop was very slow and I did the final shots in the back yard. 10-20 minutes on TriX would show the the bright stars of Orion with nicely resolved diffraction spikes. <br /><br />Under a loupe, the spikes were always somewhat unpredictable and I attributed this to focus shift due to temperature and other factors.<br /><br />During the work fitting the ground glass noted above, I found that there was a disagreement between what the ground glass showed, what the lodestar tool showed, and what the film plane showed. While putting the system together I tried to measure the distances with a depth gage and used plastic shims to move the ground glass. I found that I needed to restrict the measuring environment to a way that easily showed front and back focus. <br /><br />I built a setup that featured a tape measure laid across a table top with markers to indicate the desired point of focus. Set up the camera with the 300mm f5.6 lens about 15 feet away. This close focus required extra bellows extension, using up most of the standard rail available. I tried doing the measurement in flat light during twilight and under spot lighting from LED lamps. <br /><br />Important trick was increasing the contrast of the film used to better read the tape markings. I used the FPP Frankenstein 4x5 film, a 200 speed film. Much smaller grain than TriX - which may have been limiting my earlier attempts. Metered at box speed, plus .5 stop for bellows. Exposures were 1 second at f5.6. Full strength XTOL with a 7 minute development time to give better contrast. Under a 20x loupe, the millimeter marks were clearly visible, clearly showing acceptable depth of field of 3 cm!<br /><br />I was able to back into the correction needed by taking a look at the film negative, noting the numbers that were in sharp focus, resetting the camera visually to the desired mark, confirming with the saved screenshot of the Lodestar view. Assured that the camera was returned to its focus travel as the previous setup, I changed the position of the Lodestar to have it properly focus on the actual film plane - it had to match the numbers that were in focus on the negative. Refocused on the target point using the Lodestar, then confirmed on the glass with the 10x loupe. Eventually this told me that the shim was not the .04mm originally measured - nor the .02mm used as a step - no shim was required (which makes sense).<br /><br />One more shot on film to confirm and the ability to develop one sheet of 4x5 really showed its value. The focus was dead on where it needed to be.<br /><br />No start test done as I realized that Polaris still shows rotation in 10 minutes with the 300mm when not using a tracking mount. <br /><br />Film decisions from Calstar:<br /><br /><p></p><ol style="text-align: left;"><li> No light pollution filter to be used. The light loss is not worth it in dark skies. Under high-energy situations where sky glow would be visible it might be worth it.</li><li> Longer exposure time up to 2 hours will be used. Calstar featured exposure times of 90 minutes. I feel that a longer time may be warranted. Will have a little more than 4 hours of properly dark skies each night. Two exposures per night is acceptable.</li><li> Ektachrome 100 will be the emulsion of choice. Will plan to shoot at least 1 night of Portra 400 just for comparison.</li></ol><p><br />Target list will be the usual suspects given the limited amount of darkness available.</p><br />Stephen Migolhttp://www.blogger.com/profile/15704689614660409737noreply@blogger.com0