Finally got a chance to try my new Rubinar 500mm f8 Maksutov lens (i believe from Russian producer LZOS) for astroimaging.
This is a quick run taken in the small window this morning between moonset and astronomical twilight. Didn't bother with Pixinsight for this quicky - just calibrated and stacked with DSS and adjusted levels with Darktable.
19 x 4min guided subs @ ISO800 on the NEQ6
larger image here
Managing fine focus control is a little challenging, so i'm thinking of getting
one of these together with a B mask to assist there. So aside from the fiddly focus issue and some slight field rotation (need to do a better job in future of aligning the lens with the guide scope), i'm pretty happy with how this turned out.
For a lens that cost me less than $200 delivered, i reckon it has a lot of promise as a low-cost flat-field "apo" alternative. Only weighs ~650 grams, so it could be an option for those looking for something light and portable for an Astrotrac or similar...?