M31 with 600L

The Andromeda Galaxy is a very rewarding target, being quite big in the sky and fairly bright too. Over the years I've steadily improved on previous bests, first using the 70-200/4L, then the 100-400L and more recently the older-model (non-IS) 600/4L, some of which I've posted in here. Last week I took an hour's worth of 30s exposures through the 7D at ISO3200, f/4. The equatorial mount was my Celestron Advanced VX. They were stacked in Deep Sky Stacker, then processed through a combination of Lightroom and Photoshop CC. This is easily my best astrophoto so far. Limiting magnitude on the full-sized version is about 18.4.

Fantastic. You can still play with WB but very nice, as is.

Nice image. I have to ask though, why did you limit yourself to 30sec exposures when you were using a tracking mount?

Pax2You wrote in post #17722992
Nice image. I have to ask though, why did you limit yourself to 30sec exposures when you were using a tracking mount?

Sound question Pax2You: the reason is that at ISO3200 and f/4, my light pollution started to get quite high at longer than 30s. I'd love to have a darker site where the problem doesn't come in until much longer. I must admit I've never tried one of those clip-in filters, so I don't know if that would help there.