A Celestron EdgeHD 1100 arrived this week together with the Celestron f7 Reducer Lens. It saw first light Wednesday night, but not very clear...
I have previously used my ASI294 with my EdgeHD 800, and the combination to the right in the photo below is 133.5mm from the SC-adapter ( B ) to the sensor. That is the correct distance for imaging with the 8” EdgeHD at f10. With the f7-reducer installed I just switch to adapter A and get the required 105.0mm.
The EdgeHD 1100 require 146.05mm, regardless of f7 or f10.
The included step-down adapter ( C ) for the 11” Edge has a working back focus distance of 12.7mm and together with the 133.5mm-kit it equals the required 146mm almost perfectly. However, I am not able to reach focus. With the focus knob at max anti-clockwise to the stop, I need more. Infinity is not enough!
I desperately tried adapter A instead and found focus at a couple of turns clockwise, but the working back focus distance was then 117.7mm and the stars did not look very good.
For visual observation, with the included diagonal installed on the step-down adapter and the 23mm Luminos eyepiece, I cannot reach focus together with the reducer lens. Once again infinity is not enough. Without the reducer lens however, I find focus at about seven full turns clockwise. (I have yet to try the camera at f10)
Full focus travel on my Edge11 is 29.5 turns and it seems to me a bit strange that focus is so far off to one side. On my Edge8 the full travel is 44 turns and focus is found approximately in the middle.
Is there any 11" EdgeHD-owner out there, who can confirm that focus is found very close to infinity?
Has anyone any idea of what could be wrong in my setup?