My best "failed" image ever (M31)

[glappkaeft]

For several years I barely captured any deep sky astroimages as all I did was to tend to our astronomy clubs telescopes and activities. While running a 16" RC and a 17" Newton is really nice I wanted to have some data of my own to play with. The solution I arrived at last year was a quick and dirty AP rig (CG-5, Canon 600D, intervallometer, Sigma 24-70 or Canon 70-200mm F4L and dew heater) that I can set up with minimal fuss and leave running unattended for most of the night hoping for the best. At the moment I'm also adding a Lacerta MGen2 autoguider but it turns out my mount has a defective autoguide port.

Last Saturday was definitely not "for the best", I used the Canon lens @200mm and F/5,6 to capture M31 but I did't have light enough weight to balance the camera. I added the guidescope as a counter-counter-weight but the stars still mostly came out as bananas and L's in every direction possible (possibly I balanced it too well).

After giving up for the night I left the camera running and took 25 5 minute exposures (two good ones...). When I came home I stacked them all for giggles in DSS with a hard SD mask. When the result turned out to be much better then I expected and imported the result in the trial version Star Tools and saved the image as a 8 bit screen capture down-scaled 32%. I don't remember exactly what I did and now that I have bought a licence (and could save a high resolution 16 bit TIFF) I haven't been able to mach the result. There is certainly such a thing as spending too much time trying to save bad data and I think I have now passed it.

A sample of the stars:

Here's the result:

 

regards

Patrik Holmström

[glappkaeft]

Darn, posted the wrong image.

[MeyGray3833]

Either one of them looks fine. Good effort for sure. Unfortunately you'll definately be hooked and unable to wait until your next imaging fix!!

[Uranium235]

A good save there, SD mask can cover up many sins

Odd star shapes though, almost looks like wind damage or its been knocked. I found that with a CG5-GT, once its guiding - back well away from it.

Also, you might want to check whether your RA clutch handle is making contact with the DEC housing (can be a cause of poor guiding with this particular mount)

[glappkaeft]

Either one of them looks fine. Good effort for sure. Unfortunately you'll definately be hooked and unable to wait until your next imaging fix!!

(Un?)fortunately I was hooked already in 2007 when I got my first real telescope (8" Newton/CG-5) and it got even worse in early 2008 when I dug into my meager funds (the last leftovers from a summertime job) to get my first DSLR. It is to late to save me...

[glappkaeft]

Odd star shapes though, almost looks like wind damage or its been knocked. I found that with a CG5-GT, once its guiding - back well away from it.

Also, you might want to check whether your RA clutch handle is making contact with the DEC housing (can be a cause of poor guiding with this particular mount)

The mount was planted on bedrock and no person came close except when I checked the results but oh let me count the ways I still managed to mess it up.

1. Used a newish lens with much longer exposures than I ever attempted before, Turns out I didn't have a light enough counter weight to properly balance it.  Before I discovered that I left and helped other people (still twilight).

2. Removed the counter weight but the new lens was heavier and longer and thus required a counter weight. The first exposure looked fine (first good exposure). Left and did other stuff.

3. Attached the counter-weight again and mounted my guide scope on a dual mount bar as a counter-counter weight. Re-balanced and realigned the scope and got one ok:ish image. Left and got a cup of coffee and a hot meal.

4. ..the DEC cable got caught between the plastic covers. Fixed this and left but then... 

5. ..the mount halted at the meridian flip minutes later after I left.

6. Started a set of new exposures and checked just the first one (the second good exposure).

7. Turns out the mount is now unbalanced after the flip and most exposures are bad.

8. Redid the balance but fixed the wrong axis due to a brain freeze. The RA axis is now unbalanced and the DEC is almost perfectly balanced and is moving about due to perturbations.

9. Gave up and left the camera running and did other stuff (an attempt to catch an asteroid occultation with one of our main telescopes).