My First Galaxy

[benklerk]

Done my first galaxy last night (moon was 1st quarter). M 104 (Sombrero Galaxy) Took 15 images at 2 min but turned out my guiding software PHD2 stopped guiding. So I will try Ascom guiding instead of ST-4 next time.

Overall done 2 subs at 2 min = 4 min exposure. Camera is D7100 ISO 1000, prime focus. How do you focus using a DSLR? I usually go to the moon to focus to get fine details.

I need to learn on how to do darks, flats and bias. Any tips on how to do this, as this would reduce a lot of noise.

Update, changing to Ascom pulse guiding has made guiding better than ST-4 so far. Im getting about .7 arc min.

[bobbyf]

Hi there
For focussing for my D7000, I use nearby stars usually.
I normally crank the ISO to max in liveview and zoom in on the star.
Then just adjust focus until the star is as small as you can get it.
As for darks, just take the same pictures as your galaxy images (lights) in terms of exposure and ISO etc, but with the scope cover on.
Bias is taking shots with the scope cover on at minimum shutter speed - 1/8000s in your case (just to measure the read noise).
Flats are more difficult.
I am still learning too and have tried T-Shirt flats, where you take you take your imaging gear (exactly as you had it) and point the scope at a white LCD screen with a white T-Shirt over the scope.
I adjusted shutter speed and ISO to achieve a histogram that is roughly 1/3 from the left. (read off the internet)
It does work, but I'm not sure if it's better or worse than other methods.
Hope this helps
Cheers
Bob

[muletopia]

I became so frustrated with trying to focus on any object using the LCD screen I bought a cheap 12 volt television, When connected to my Canon 60da by HDMI the LCD screen view is transferred to the TV. The large picture enables pretty good focusing. A bonus is that images can be examined as they are captured. Not great resolution but obvious image problems show up.
I don't know if this is an option with your Nikon camera.

Cheers
Chris