I'm now enjoying taking photos with M42 lenses more than the K mounts. Using Aperture priority and a couple stops of compensation they expose well.
First star shot is with a M42 SMC 135 f3.5 which I am growing very fond of. Exposure was 20minutes (which is the longest I have tried so far). Like the way the colours came out.
Second is a moon shot with Soligor 400 f6.3. Heavily cropped (this is full crop) but still not bad. I have had some good results with this lense despite being a cheap purchase (US$21).