imaging with the moon up

[scitmon]

It looks like a couple of clear nights are ahead this weekend for me.  Unfortunately the moon rising at 10pm is ruining prospects of a good imaging session, but I think I'm going to try anyway just to get some practice in.  My question is, knowing that faint nebula DSO imaging (with a DSLR) is challenging in moon light, is M31 or M33 a bit easier?

[vlaiv]

Everything is in principle effected in the same way - faint stuff the most effected, bright stuff a bit less. Targets close to Moon - the most, further away, a bit less.

If you want to take the advantage of clear skies - by all means, go ahead, just moderate expectations, SNR in Moon light is going to be really affected, but then again - it will provide suitable post processing challenge to practice with.

I would go for M31, M33 is low surface brightness target, so it will be affected quite a bit. M31 has parts of galaxy that are low surface brightness, so expect quite a bit of noise in those. Also you will probably have gradient due to moonlight.

I just had a look in Stellarium (don't know how much difference is there due to location), but both M31 and M33 are far west when Moon appears, so you should get a good imaging session for any of them if you start couple of hours prior to time the Moon rises.

[pipnina]

1 hour ago, vlaiv said:

Everything is in principle effected in the same way - faint stuff the most effected, bright stuff a bit less. Targets close to Moon - the most, further away, a bit less.

If you want to take the advantage of clear skies - by all means, go ahead, just moderate expectations, SNR in Moon light is going to be really affected, but then again - it will provide suitable post processing challenge to practice with.

I would go for M31, M33 is low surface brightness target, so it will be affected quite a bit. M31 has parts of galaxy that are low surface brightness, so expect quite a bit of noise in those. Also you will probably have gradient due to moonlight.

I just had a look in Stellarium (don't know how much difference is there due to location), but both M31 and M33 are far west when Moon appears, so you should get a good imaging session for any of them if you start couple of hours prior to time the Moon rises.

I no longer have the image, (might be in my post history) but I managed to capture bits of the heart & soul nebula with a DSLR on a tripod under a full moon. it wasn't a great looking image but you can get a lot from moonlit skies- you're just more limited by maximum exposure time & added gradients.

[Gerry Casa Christiana]

I find that with the moon it's possible but only to the point it starts rising in the sky. I remember doing M31 getting some nice frames then noticed all of a sudden I lost detail. The moon had risen! But depending on where you are you should still get a few hours after it gets dark before the moon makes a appearance. 

Gerry

[vlaiv]

The thing with the Moon is that it lowers SNR in the same way LP lowers SNR, so one can obtain same image in moonless conditions as would be able to do so in full Moon next to the target.

Difference is only in the amount of imaging time needed to do so (and gradients present, which in theory can be removed, maybe even easier for the Moon case than it is for LP case, but in each case one needs some additional data like direction of gradient, etc ...). How do we improve SNR - simply by adding more and more subs.

So if you have plenty of time (4-5 nights) under clear skies with Moon out you will be able to do the same image that you would normally do in single moonless night. Exact increase in imaging time can actually be calculated if all variables are known (like sky brightening due to moon)