Monday, September 3, 2012

M31 with the skyglow filter

So, I put the starfinder under the guidescope bracket. It's pretty snug aligned to the guidescope, i.e. it won't wiggle too much. That will make alignment and calibration SO much easier. I should get some double-sided scotch tape to fix it further.

Now, I had to start the night with a whole lot of adjustment:
  1. Rough adjustment of the starfinder (not easy if the scope is not tracking yet)
  2. Alignment, calibration and polar alignment
  3. With tracking, adjustment of the starfinder and focusing and adjustment of the guidescope
  4. And now another round of alignment, calibration and polar alignment - this last run-through was a breeze!
Then I tried to get PHD working. I could easily get the starshooter camera to focus (haleluja for perfocal rings!) But when it calibrated, it could not calibrated the dec axis. And when I tried guiding, it went quickly out of center. I decided to rather take some photos instead of trying to get PHD to work.

First, I wanted to take photos of M57. But it came out very small in the photo - I should try that without the focal reducer. But I didn't want to take the whole camera off and such.

I tried to take longer exposures from M31: 4 minutes. The photos looked pretty good, but of course very saturated. So, I tried out the light pollution filter. The photos came out very blue, but not too saturated.
I set the scope to take pictures the entire night. When M31 was behind the gigantic redwood tree, I started to take darks - and then set the alarm to 1am to get up and setup the scope again for lights.

In the morning, it was clear, so I could take flats and dark flats. But it turned out that the scope stopped tracking again. When I read more about it, I found out that CG-5 scopes stop when an object crossed the meridian. Obviously, they can't track further. I was wondering if there is some option to automatically flip around, but that's not possible :-(

But at least I had 40+ pictures - each 4 minutes long.

I first stacked with DSS. Nebulosity could not deal with the blue hue. So, I tried to do some basic post-processing in Photoshop instead:

Not too bad. You can see some details of the spiral arm - but the bright center is overpowering. I need to figure out how to combine two images to get this better.