M31 with a Modified Canon 600D

[Mikey0368]

I have another thread running in the imaging forum but this is a fairly basic question so I thought I would put it in here.

I've been dabbling with images of M31 but I'm not sure how many subs I should be taking and how long the exposure should be. Could someone give me some pointers please?

My equipment is an HEQ5 Pro with Rowan belt drive, 8" reflector and a modified Canon 600D. I'm using digicam Control and a Bahtinov mask to get focused. Also, I'm in Edinburgh so there's a bit of light pollution.

Thanks.

[rickwayne]

The rule of thumb is to expose each sub so that it's showing the histogram peak (most numerous pixel value, aka background) at about the 1/3 mark. Start with 30 seconds, try a few doubling from there (1 minute, 2 minutes, etc.)

As far as the number...ALL THE SUBS! SHOOT ALL THE SUBS!

Seriously, in light pollution that's your best shot. Take as many as you can stand. More is better, up to a point of diminishing returns, especially if you find yourself having to do shorter subs. At 30 seconds, several dozen at least. Aim for an hour or more of total integration time, and see where you stand.

Can't wait to see your results! I love Andromeda, a newb like me can get some half-decent images, while an expert can still strive for a better one.