Analog System notes from Sept 10 2021:
Here are notes written just before Calstar 2021 as a summary of the kit.
As mentioned earlier, I have a new analog setup.
It consists of a 4x5 monorail camera with an autoguider.
Camera is the Horseman LE held in place with two vixen-style feet.
The autoguider is a Stellarvue 50mm guider with SX superstar.
All mounted on a single 24 inch dovetail.
The camera has geared movements and a geared focus along the rail. This makes the whole system stiff enough to handle the changing demands of astrophotography.
The whole system is riding on top of my 2004 vintage Losmandy GM8. This mount has been upgraded a few times, most recently with McLellan gear boxes and new bearings. Both axes are set up with the one piece worm blocks to eliminate misalignment. Oldham couplers have been replaced with Ruland double disc couplers to eliminate backlash. 1 inch thick aluminum spacer blocks have been added in the RA and DEC axes improving clearance.
The Gemini 1 system was repaired by Michael Hermann in 2019 to rebuild the serial circuit as the controller was dying.
The system whirrs and runs with very few issues.
Guiding is done via PHD2 with multistar enabled. Most guiding plots are well within 2 arc seconds RMS, much smaller than the expected scan resolution.
In testing, I have run this mount with 1 hour subs. Just need to watch for collision issues.
Testing of lenses has given these results:
Schneider-Kreuznach Super-Angulon 5.6/90mm yet to try. Probably good wide open. Expect to use with roll film for panoramas.
Schneider Xenotar F3.5 135mm - soft on edges, strong light fall off when at F4. Non astro lens.
Rodenstock Apo Sironar W 150mm F5.6 Lens - sharp wide open.
Schneider G-Claron 210mm F9 yet to try - F stop indicates non astro lens.
Schnieder APO-Symmar 300mm F5.6 - added 77mm filter ring behind the lens, sharp at max aperture
Schneider KREUZNACH APO-TELE-XENAR 400mm F/5.6 Compact MRC - step up ring behind the lens for filters. appears to be sharp at max.
Sankyo Kohki Komura 500mm F/7 Lens - yet to try. Expect some possible purple fringing.
I do not expect to get any additional lenses for this system. Eventually I do anticipate mounting the lens from my great grandfather's Kodak folder to shoot portraits.
I've found out that at least one of the film holders that I use have curl issues. I am working to identify these holders to eliminate them from critical applications.
I know that one option is to make a vacuum back. That may still be something to consider.
For what it's worth, one holder is already dead on, so that's good news. I will check the others with a micrometer to see if there are variations.
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