Adjusted my old Takumar 300mm f 4 prime lens so it would focus to infinity on the modded Canon 550d. Haven't used this lens for astrophotography since it was attached to a Pentax SLR loaded with polyester film!
I think the coatings on the glass aren't as good as they used to be and there was a fair bit of CA at f4 so I shot this at F8. It still didn't eliminate the CA but at least I got what I was after with the help of a CLSCCD clip in filter, in Bortle 6 skies. My aim was to get a shot of the Lobster and Cats Paw centred nicely in the frame. The 300mm focal length coupled with a APSC sensor made that happen.
I stacked this in Siril for the first time ( a little more involved than DSS ) and processed it in StarTools and Photoshop. 30 x 120 secs 3200iso CLSCCD filter and 45 x 60 secs 1600iso UVIR cut filter. Omega Centauri was 18 x 60 secs at 1600iso UVIR cut filter, stacked in DSS.