M31 2nd attempt last night, three frames

[David010167]

Last night I had a rare opportunity of no clouds, so after a good look at Jupiter I set up to image M31, this is the second image I have taken and I still have a lot to learn.

I made a few mistakes last night; the framing is poor.

I also had a lot of problems with APT and my 7D, but I have realized this morning that not turn on on MLU on the camera caused some of my problems. I also ended up with the camera only taking three frames and than a last from of 9000+ seconds, again I think related to the MLU mistake.

This is three frames of 10 minutes each at ISO800, staked in DSS and then curve adjusted in CS5.

With a bit of luck tonight is looking clear, so I will have another go and try to get better framing and more images to stack.

Also thanks to Sparrow for mentioning in another thread how to reduce the blue I had in my first attempt at M31 due to the CLS clip filter.

regards

David

[dc509]

fab image! and only your second - you've put my feeble attempts to shame...

d

[Bizibilder]

Exellent first attempt!!

Don't forget to take (and stack) some darks and, if possible, some flats.

Darks? Easy put the lens cap on and take exposures that are the same length as you "frames" (or lights). Do this anytime but they should be at the same temperature as the "frames"

Flats? Try and arrange a diffuse white light down the scope and take using the EXACT same set up as your "frames" - exposure - use Av (automatic exposure) or try around 1/25sec. To get the "diffuse light" I used to reflect my lantern off a white t-shirt into the tube!! it did work! Do these with the camera/scope still set up.

You will need maybe 20+ of each.

Stack using Deep Sky Stacker. These extras will get rid of the vigneting and any gradients as well as reducing noise.

Confused? Take it one step at a time - just do the darks for the time being.

[David010167]

Thank you for the comments.

At the moment I am letting the camera do an in camera dark frame for each light frame, it is simpler for me whilst I get used to it all. When I get mo comfortable with the process, I will turn off the in camera noise (dark frame) process and try them myself along with flats etc.

One issue with letting the camera do dark frames is it does it as you shoot, therefore a 600 second exposure takes 1200 seconds, since the camera takes first the light frame and then the dark frame. In theory this could lose valuable imaging time, instead I could take all the lights in one go, and if the clouds/rain roll in, I can then take the darks when I put all the kit away.

Does all the above make sense, have I understood the process correctly?

Regards

David

[Taff]

Hi David' That's a nice capture of m31 with m32 and m110 on view.Mark

[Cloudwatcher]

With a bit of TLC in PhotoShop you can drag out a reasonably detailed image once you get rid of the green and magenta. Unfortunately this does result in the loss of some of the fainter background stars but on the upside M31 stands out more and can be enhanced as a separate layer to bring out the detail.

Anyhow,heres my edit which has been flipped as it looks better this way up.

[David010167]

That is excellent Cloudwatcher. Can you explain what you did in Photoshop to achieve this. From what I can see the contrast has gone up quite a bit and the black is back around the spiral.

Regards

David

[Bizibilder]

You can take your "Dark" frames at anytime - I usually take them on cloudy nights. Just record the temperature at which you take them as well as the length of exposure. I do them in the garage as it is often cool enough and have built up a set that I now use regularly. I will retake them from time to time. No point in wasting good clear nights with the lens cap on!!

[David010167]

Hmm cannot seem to delete a duplicate post.

[David010167]

Hmm cannot seem to delete a duplicate post.

You can take your "Dark" frames at anytime - I usually take them on cloudy nights. Just record the temperature at which you take them as well as the length of exposure. I do them in the garage as it is often cool enough and have built up a set that I now use regularly. I will retake them from time to time. No point in wasting good clear nights with the lens cap on!!

That makes a lot of sense. I will change my settings on the next opportunity I have.