Made some final adjustments to the newly restored Edmund Space Conqueror mount the other day and decided to try taking an image of M13 through it using this crazy camera bracket gizmo Edmund sold with it. I was skeptical that it could even work, especially with no way to guide. Balancing everything out, polishing, lapping and greasing the gears was key. The work paid off! Exposures below 30" were mostly good. Even some at 60" were acceptable, showing minimal PE. I think the new Teflon bearings are helping too. When properly balanced, it moves effortlessly, no slop or binding anywhere. I will follow up this post with a careful PE check next clear night. I think it is drastically improved.
I searched all over for the formula to figure focal length of the "afocal" set-up below but couldn't find anything. (nobody does this anymore for many good reasons). Then I remembered good'ol Sam Brown, "All About Telescopes". He had it on page 59. The internet didn't.
With this set up on the 6" Space Conqueror, my lens was set to 35mm over a 40mm EP, so it is 35mm/40mm x 1231.9 = E.F.L. 1078 @ f/7. (1231.9 is metric the 48 1/4" FL mirror). Effectively, the camera lens functions as a focal reducer! Not a bad set up at all, so long as the knobs are tight
The frame is a stack of unguided, (of course), short exposures. On close inspection some trailing due to periodic error can be seen but I am happy to report this old telescope drive is working better than it's original 1962 factory condition, (the motor however had to be replaced with a 1973 unit).