My latest picture shows M13, that was shot with my ASI183 Mono and a LRGB filter set that was sold by TS. There are some issues, that I have to solve for future images. The cluster itself is quite ok for the relatively short exposure time. The brighter stars show two different effects. A bit by accident, I noticed, that my Explore Scientific MN-152 comet hunter isn't that good. The front lens of this Maksutow-Newton seems to have problems with some colors. The star beams are colored red on one side of the star center and the other side is colored blue. I was able to reproduce this issue with my Touptek ATR3 color camera as well as with my ASI183 using LRGB filters. I did some tests and removed all possible filters from both cameras light paths but the problem was still visible. That is really bad...

The second problem are the halos around the 4 brightest stars. They seem to be most obvious in the blue color channel and for this reason I think the blue filter is the worst one in terms of quality. But they are visible in the other color channels as well. I think, this problem could be solved. Because I had really good experiences with an Astronomik Ha filter, that solves this problem in other cases, too, I orderd a set of their LRGB 2c filter set. They are quite expensive and it was really a hard decision, but I hope they work as well as their narrow band cousin.

Sadly, the colored beams on the stars are a very different problem and can't be removed that easy. I guess, the glass elements of the scope do cause this issue. Because the two cameras I used to check this are quite different, I should expect different behaviors which did not occur. So the cameas should not be causing that issue. That is really sad!!!

But beside that, I do like the picture myself. Maybe, my experiences with that image will help someone out there. Theres always a lot to learn...