1st Real Image - M31 Andromeda

[agthomson]

Evening all,

A few weeks back I bought my new WO ZS61 to replace an old Super Takumar 200mm lens I was using on my Sony A6000 for basic astrophotography (paired with a SW Star Adventurer). 1st real chance I got to use it, and the results aren't that bad all things considered! Andromeda was quite low in the sky when I started, in a light-polluted direction, so unfortunately once the orange gradient is removed I lose a fair bit of the red colour from the galaxy. Image consists of 40 x 30s lights (to avoid Sony star-eater), 25 x dark, 50 x bias all stacked in DSS. Initial processing in PixInsight (masking, gradient removal, curves, noise reduction), final processing in Photoshop (curves, saturation, rotation).

Issues I've noticed include: slightly out-of-focus (need to buy a Bahtinov mask), slight star trails from poor polar alignment, odd shape to the stars (notch missing from bottom left - ideas?).

Pointers welcome! Also, i'm 100% sure this could be processed better. 1st time using PixInsight, and I'm no wizard with Photoshop.

[kirkster501]

An excellent result, well done.  I agree with your synopsis in that your focus is very slightly out.  We're splitting hairs and you did ask so that is something for you to work at.  Nail that and this would be a corker.

Are you guiding this?  If the dither is wrong it can lead to all strange artifacts and spots/notches.

[Starlight 1]

41 minutes ago, agthomson said:

Issues I've noticed include

Nice looking M31 well done, no issues that I can see

[agthomson]

1 hour ago, kirkster501 said:

An excellent result, well done.  I agree with your synopsis in that your focus is very slightly out.  We're splitting hairs and you did ask so that is something for you to work at.  Nail that and this would be a corker.

Are you guiding this?  If the dither is wrong it can lead to all strange artifacts and spots/notches.

Thanks for the comments. I have a few things I want to work on, and focus is definitely high on the agenda! This was unguided, as I don't see too much point guiding with 30s subs. 

[Allinthehead]

That's a great first. You must be chuffed with that. You should try to gather a few hours worth to really make it shine. Are darks worth the bother with this sensor?

[agthomson]

Possibly not, but I'll collect them regardless. I can always stack with and without and see what's best. The sensor seems fairly insensitive to ISO, so I have to play around with that as well. This was shot at 6400 but the same ISO on say the Pliades would blow the stars out.