Nickb

I was looking for the ASA8H corrector model number and found it. It is 3KORRH8.

Hi Mark, This is very helpful! That is what I suspected but seemed counterintuitive since the focuser tube is not angled towards the center of the secondary. I recently moved to a full format cmos camera and am having problems with peripheral stars. I’ll go back to the ASA procedure (with your additional mirror check) and let you know the results. Many thanks! Best, Nick

Hi all, I have an ASA8H and recently purchases Catseye collimation tools. The Telecat XLS cheshire sight tube indicated that the secondary was not centered under the focuser tube. I moved the secondary back 5mm to center it. See pic of adjusted secondary through the Telecat XLS. I had previously followed the ASA procedure to position the secondary using a laser (Glatter) in the focuser with the secondary rotated 90 degrees, and moving the secondary back until it intersected the laser. This placed the secondary at about the same position as it was originally (5mm forward of the focuser axis). Does anyone know if a Cheshire can be used to position the secondary mirror? If a cheshire will work, why does it result in a different position than the ASA procedure? Thank you for your help! Regards, Nick