There was a thread about his last year but I cannot for the life of me find it.
Anyway with a mono camera you can do some pretty good imaging with an achromat. Just find a flattener/reducer that is a good fit and they make for some very good and sometimes fast imaging scopes.
Here are two combos that I found work.
Skywatcher ST120mm Achromat f5 version. Use the Skywatcher 80ED Evostar 0.85x focal reducer with it and its a perfect match.
Another combo that I found works is a Orion 100mm Achromat. No long in production. Use the same Evostar 80ED 0.85x focal reducer.
I use ASTAP for stacking so it can scale the image if there is a difference in size though that difference is usually less than 1mm in FL. I think just about every stacking solution out here can scale images during stacking except maybe DSS which is ancient anyways.
I made a video of my findings here in the first post.
One thing I recommend if you want to try this is to get narrow band pass filters. I started with 7 and 8.5nm bandpass filters and have switched to 3.5 and 4nm band pass filters. They improved star size a good bid. Almost cutting their sizes in half.
And some photos. Because photos do not Lie.
Edited by Grimstod, 20 January 2022 - 11:19 AM.