I recently purchased a ZWO ASI 071. I plan on attaching to Celestron CPC1100. I will be using the Celestron focal reducer. I am curious about focusing. I believe in order to get to focus I will need to use both the extenders supplied. Even with the extenders I am not sure if I need to focus 'out' or 'in'. I know with my Nikon D750 I had to focus a great deal 'out'. Does anyone have a similar setup? If so what do you do to get proper focus.
Roger
menardre wrote:I recently purchased a ZWO ASI 071. I plan on attaching to Celestron CPC1100. I will be using the Celestron focal reducer. I am curious about focusing. I believe in order to get to focus I will need to use both the extenders supplied. Even with the extenders I am not sure if I need to focus 'out' or 'in'. I know with my Nikon D750 I had to focus a great deal 'out'. Does anyone have a similar setup? If so what do you do to get proper focus. Roger
I recently purchased a ZWO ASI 071. I plan on attaching to Celestron CPC1100. I will be using the Celestron focal reducer. I am curious about focusing. I believe in order to get to focus I will need to use both the extenders supplied. Even with the extenders I am not sure if I need to focus 'out' or 'in'. I know with my Nikon D750 I had to focus a great deal 'out'. Does anyone have a similar setup? If so what do you do to get proper focus. Roger
I was able to answer my own question last night. I mounted the ASI 071 onto the Celestron T adaptor, and the focal reducer. At first I used 2 of the 21mm extenders, but this was too much. Even using 1 extender required me to focus 'out' quite a bit. My plan is to reduce the backfocus distance (shorter extender) so that I do not have to focus 'out' quite so much.
usually reducer require 55mm back focus distance
so you have to use the proper extender
otherwise you cannot get perfect stars
