Saturday, February 23, 2013

Leo Triplet

Leo Triplet by S Migol
Leo Triplet, a photo by S Migol on Flickr.
Via Flickr:
Leo Triplet with 31 frames of 1200 seconds at 100 ISO for 10 hours and 22 minutes of integration.

I wanted to give a lighter touch to the processing on this shot given the work I'd done on the Sh 290 object. There's still a mottled background and so it's not as pretty as if I'd driven it darker like I do on some other targets.

Taken from home where the light polluted skies give an orange color to the background.

Standard setup. Camera was using the new cooler arrangement, so the EXIF temps were reading about 4 C and the thermal probe was mostly at 0C.

Here's the plate solve results:
Referentiation Matrix (Gnomonic projection = Matrix * Coords[x,y]):
-0.000001111043 -0.000530669418 +0.671544214950
+0.000530622860 -0.000001324026 -1.003330659875
+0.000000000000 +0.000000000000 +1.000000000000
Resolution ........ 1.910 arcsec/pix
Rotation .......... 89.866 deg
Focal ............. 655.40 mm
Pixel size ........ 6.07 um
Field of view ..... 2d 0' 36.3" x 1d 20' 19.8"
Image center ...... RA: 11 20 04.352 Dec: +13 24 25.54
Image bounds:
top-left ....... RA: 11 22 49.341 Dec: +12 24 10.81
top-right ...... RA: 11 22 49.684 Dec: +14 24 45.59
bottom-left .... RA: 11 17 20.399 Dec: +12 23 58.83
bottom-right ... RA: 11 17 17.980 Dec: +14 24 33.52

Thursday, February 21, 2013

SH 290 - Ugly and Faint

SH 290 by S Migol
SH 290, a photo by S Migol on Flickr.
Via Flickr:
SH 290 as seen from the nights of Feb 8 to 17 2013 in the back yard. This is from a stack of subs collected to test flexure. I'd selected this target because it crossed the meridian at a time when I could get the scope set up and let it run. I was more interested in seeing the trailing of the stars and if I managed to get some nebulosity, great.

I threw a stack of subs at DSS to see what would stick and it gave me 76 that qualified for a total of 25 hours 26 minutes of integration time.

As could be seen from the earlier screenshots of the PI window, there was some data visible but it was hiding deeply, just above the skyglow. The real challenge was separating the useful data from the noise.

In the end, I went away from my normal habit of using the masked stretch script and used the auto histogram tool. That helped pull the lower regions apart so that I could gently nudge the colors from the background. The atrous tool was used to aggressively control the noise -- and it worked well.

I think the annotated image really surprises by showing all the galaxies lurking in the background that I would normally cover by sending the background darker.

I think that this has taught me that there is still lots to see from the back yard. The 20 minute subs seemed to have helped. I could have gotten better contrast by going to a darker site. A more aggressive light pollution filter might have helped but it would have left more noise.

Also, there are some uncontrolled dust motes because of missing flats. Not unexpected given the way I was messing with the camera during these sessions. This was done just after I'd modified it and put the new cooler in place.

Here's the plate solve results from PI:
Referentiation Matrix (Gnomonic projection = Matrix * Coords[x,y]):
+0.000001921229 -0.000530936211 +0.625360829652
+0.000530835145 +0.000002080507 -0.911281838161
+0.000000000000 +0.000000000000 +1.000000000000
Resolution ........ 1.911 arcsec/pix
Rotation .......... 90.210 deg
Focal ............. 655.10 mm
Pixel size ........ 6.07 um
Field of view ..... 1d 49' 4.0" x 1d 15' 25.7"
Image center ...... RA: 08 54 14.323 Dec: +08 55 12.07
Image bounds:
top-left ....... RA: 08 56 45.857 Dec: +08 00 30.10
top-right ...... RA: 08 56 48.215 Dec: +09 49 32.40
bottom-left .... RA: 08 51 41.192 Dec: +08 00 47.80
bottom-right ... RA: 08 51 42.030 Dec: +09 49 50.17

Tuesday, February 19, 2013

M81 M82

M81 M82 by S Migol
M81 M82, a photo by S Migol on Flickr.
Via Flickr:
M81 M82 as seen on the night of Feb 16 just after midnight. I set up the camera and let it run from transit through until the fog came in at 3:30 am. This was in the backyard!

This is the result of a stack of 10 subs at 1200 seconds each for a total of 3 hours and 20 minutes of integration. There were some clouds that came through during the session so one frame was dropped in the middle of the sequence. The ISO setting for the camera was 100 ISO - something that I've been trying for a while to understand how to best use the low noise characteristics of this CCD based DSLR.

Friday, February 15, 2013

Muddy Waters - Flexure and PEC

What's going on in this graph?
  1. During the first image (which shows up as 0 because there's no previous data for a difference) PEC had been trained at 4x the worm cycle, as was seen in the post made earlier.
  2. Thus, what is seen in that 20 minute sub from 9:49 to 10:09 is the results of PEC being on and the target crossing the meridian.
  3. It's interesting that the sub that covers this zenith is the worst and as soon as it goes past the top the target is fine.

Flexure and Other Gremlins


What a day and night!

Earlier during the day, I did a sweep of nuts and bolts and screws on the scope to see what might need tightening.  Here's what I found:

  1. I tightened the tripod screw and support on the rings.  Ended up needing to use a wrench to get them tight enough.  In the end, this is a much more secure fit.
  2. I noticed that the grub screws connecting the feather touch focuser on the scope body could use tightening.  Each got 1/8 turn.
  3. Tightened the bolt holding the focuser support rail.  This didn't need much, but since I was checking things, it was good to put some consistency on it.
  4. While I was looking at the main rings, I noticed that I could see light under the edge of the rear ring.  Thus, I loosened it and put an aluminum shim on that side.   
In the evening, I put the scope to work right away.  Of course, focus was off, so I'll get very limited data from that period.

Wednesday, February 13, 2013

Flexure Work

Flexure Work by S Migol
Flexure Work, a photo by S Migol on Flickr.
Via Flickr:
I've been testing flexure this new moon cycle. This is the latest configuration of the scope.

What's changed recently:

  1. I've moved the rings on the main scope out to near the ends of the dovetail plate. This seems to give some stability to the overall system.
  2. I've removed the ring around the focuser on the SV70ED guide scope and replaced it with the foot that it uses. Hopes are that this will provide a firm base rather than a floating tube.
  3. I've added a direct support for the DSLR camera via the tripod socket. This has helped remove any movement that the camera has. Now the remaining flexure is just from tube movement rather than from focuser sag.
  4. I've also added another layer of aluminum strip metal under the main rings to shim them up and remove the gap that was left over after I removed the felt. It's an ugly job but it works.
  5. I still have the metal straps in place. I also have added an additional finder on the scope but it's just floating rather than providing support.

Tuesday, February 12, 2013

Witch Head Nebula (DRAFT)

Witch Head Nebula (DRAFT) by S Migol
Witch Head Nebula (DRAFT), a photo by S Migol on Flickr.
Via Flickr:
A work in progress, this is the Witch Head Nebula (IC 2118) near Rigel. Seen over two nights of data collection at Montebello OSP.

Monday, February 11, 2013

Optimizing TEC

I've been using a Tellurex C2-30-1505 device (Qc 46 Watt at 15V) in the new configuration.  After spending some time at this page I found that for the load of 5-10 Watts and the voltages I am using, a better match would be a device with a Qc of 20 Watts.  Luckily I had one in the Tellurex C2-25-1502.



What did this mean for the configuration?

Sunday, February 10, 2013

Flexure Testing (Another Dead End Found?)

As a part of the modifications to the camera, I've opened up access to the tripod socket.  This had been obscured by the wool sock in the past.  Now that I've made the configuration a bit easier to use, I can attach the camera via the socket.

This meant that I had to fabricate a small supporting bar from some of the aluminum bar that I had around.  I also had to put a gentle S shape into it to allow clearance past the Losmandy ring set.


Thursday, February 7, 2013

Losing 10 Ounces

Ready for more testing. by S Migol
Ready for more testing., a photo by S Migol on Flickr.
Via Flickr:
The new configuration is complete.

The cooler is assembled with a trimmed finger in place. There's a new peltier device, a 40 Watt unit from Tellurex. Testing during assembly required several stops and starts. I found that I couldn't rely on the thermal gel material at all to help with heat or cold sinking the device. Instead, I had to use some thermal compound that I had lying about. I may upgrade this in the future.

Monday, February 4, 2013

It Starts with "B"

It Starts with "B" by S Migol
It Starts with "B", a photo by S Migol on Flickr.
Via Flickr:
Black/Bulb

This is submitted for the Macro Mondays challenge of "It Starts with B" for Monday, February 4, 2013.

This is a macro image of the puffer bulb that I use to keep my optics and sensor clean. It's a trusty little device that has served me very well.

Here I'm holding it in front of my camera. On the right is a flash, snooted and gridded at 1/16 power. This is the source of the reflection off the black rubber and nozzle. High and to the right are two additional flashes at 1/16 as well to give fill and light the background. I measured the light to ensure that I could use the F stop I wanted to give decent depth of field.

Taken with the Pentax K10D camera with the SMC PENTAX-DA 1:2.8 35mm Macro Limited lens. PP with LR3 to convert from RAW and upload.

Sunday, February 3, 2013

Marc and Kaori

Marc and Kaori by S Migol
Marc and Kaori, a photo by S Migol on Flickr.
Via Flickr:
On January 26, 2013, we went to visit Marc, Kaori, and Kylie at their place. After lunch we got some pictures.

I had the chance to shoot digital, 135, and 120 film.

Here's the 120 as shot with the Pentax 67 camera using the SMC Pentax 67 1: 2.4 105mm. Settings were sync speed and F4.5.

Friday, February 1, 2013

IC 443 Jellyfish Nebula

IC 443 Jellyfish Nebula by S Migol
IC 443 Jellyfish Nebula, a photo by S Migol on Flickr.
Via Flickr:
IC 443 Jellyfish Nebula as seen from Jan 12 to Jan 18, 2013 in the back yard.

This is a total of 162 subs at 10 minutes each giving 27 hours of integration on the subject. The weather was clear and very cold - each night dipped below freezing which is rare for the area. Camera temperatures were nearly all at 3-4C with the cooler running.

80 minutes

80 minutes by S Migol
80 minutes, a photo by S Migol on Flickr.
Via Flickr:
Holding at 4C. The heat sink is rather warm and makes me think that this might be the limiting factor. Without a better heatsink the cooler might not be able to drop the temperature more. I futher tested this idea by putting a larger table fan near the heatsink and allowing it to blow on the device. Only by this method was it able to reach 0C.

55 minutes

55 minutes by S Migol
55 minutes, a photo by S Migol on Flickr.

Via Flickr:
Maybe 4C.

45 minutes later

45 minutes later by S Migol
45 minutes later, a photo by S Migol on Flickr.

Via Flickr:
Dropped to 5C. Note how the Watts remains high, even though the current drops.

35 minutes

35 minutes by S Migol
35 minutes, a photo by S Migol on Flickr.

Via Flickr:
Dropped to about 8C.

6:20 Minutes

6:20 Minutes by S Migol
6:20 Minutes, a photo by S Migol on Flickr.

Via Flickr:
Dropped further to near 10C.

4:10 Minutes

4:10 Minutes by S Migol
4:10 Minutes, a photo by S Migol on Flickr.

Dropped further to 13C

At 2:10 minutes

At 2:10 minutes by S Migol
At 2:10 minutes, a photo by S Migol on Flickr.

Via Flickr:
The temp has dropped a slight bit from the starting temperature (was 26C, now is about 18C).

0C after 2 minutes

0C after 2 minutes by S Migol
0C after 2 minutes, a photo by S Migol on Flickr.

Via Flickr:
Note that the Watts has dropped a slight bit even though it's set at 0C.

At Minimum

At Minimum by S Migol
At Minimum, a photo by S Migol on Flickr.

Via Flickr:
This is set at the final stop on the dial, just below -20C. Note that there is no additional current draw vs the 0C level.

Set at 0C

Set at 0C by S Migol
Set at 0C, a photo by S Migol on Flickr.

Via Flickr:
This is supposed to be ideal. Just after starting the run. Note the 43 Watts consumed and the Amps.

At ambient

At ambient by S Migol
At ambient, a photo by S Migol on Flickr.

Via Flickr:
When the temperature gauge is just below ambient, then the current starts to ramp up. Note the watts on upper left and current draw on upper right.

Idle Power

Idle Power by S Migol
Idle Power, a photo by S Migol on Flickr.

Via Flickr:
This is the current draw of the power circuit and the fan. This is a baseline.

No Power

No Power by S Migol
No Power, a photo by S Migol on Flickr.

Via Flickr:
Note the max voltage in the bottom right display.

Exposed Finger

Exposed Finger by S Migol
Exposed Finger, a photo by S Migol on Flickr.

Via Flickr:
This is how the finger looks as currently configured. Note the layer of cardboard between the LCD and the copper. This should provide a small amount of insulation so that most of the energy goes into the finger and thus into the body of the camera rather than being wasted on cooling the LCD. Currently there is a thin layer of thermal compound on this copper plate to improve transfer of heat.

Exposed Base

Exposed Base by S Migol
Exposed Base, a photo by S Migol on Flickr.

Via Flickr:
Note the way the finger goes into the camera body here. Also note the small thermistor probe. I slide this into the gap and let it touch the assembly inside there. Most recent test has a bit of thermal compound on the probe to improve reading.

Insulated Base

Insulated Base by S Migol
Insulated Base, a photo by S Migol on Flickr.

Via Flickr:
This is how I wrap the base of the camera with the wool sock. This provides 4 layers of wool material to give insulation. I've noticed that once I wrap the camera this way, there is no rime ice forming.