Orion Nebula - fix or scrap?

[edarter]

Hi,

Last night was very clear in my part of the UK and I couldn't resist another session capturing the Orion Nebula. Being the complete novice I am though I got my camera orientation different to the previous session that I had done and the subsequent stack from both sessions demonstrates this below. The question though is whether this is fixable in Photoshop or whether I just scrap it and write off one set of subs.

Thanks
Ed

[geordie85]

The easiest fix for this would be to either crop or select intersection alignment when stacking 

[cjdawson]

Whatever you do. DO NOT SCRAP ANY IMAGE... EVER!

Disk space is relatively cheap.  So, never scrap your images, not matter how bad you think they are.  Over the 15 years that I've been in the hobby, I have taken nowhere near enough images.  I've lost some of the frames that I have taken.  Some of them where extremely bad.    My favorite of these, is an aweful 10 min, unguided exposure on the Great Orion Nebula that I took with a slide film based SLR.  The image was a good exposure, however there were problems with it.  The whole image shifted in a Zig-Zag fashion.

Years later, I was a asked to give a talk on Astro photographer.  Pretty much an astrophotography for dummies.  It was a run down of the kit that I used, the problems that I faced and how I solved them.

The problems were....

1. power

2. dew

3. focussing

4. long exposures.

 

The solutions

1. mains power, or really big battery (I use 70Ah as a matter of course)

2. Dew shield + Dew heaters  + Hair dryer (just in case)

3. Bahtinov mask and use of live view - or software to help get that focus spot on.  Also, electric focusser, so make life easier.

4. This is where that photo came in.  Using it, I was also to explain how polar alignment was important - vertical movement in the zig zags.    PEC - horizontal movelemtn in the Zig Zags.  Also, atmospheric turbulance and refraction - minor wobbles on the lines.   Importance of reducing light bleed - there was a red huge over the image, caused by a small led in the view finder!    The solution was proper polar alignment, and to use Autoguiding.   But that one image had alot to say, and whilst when I took it, I thought it was a horrible image, it proved to be extremely useful.

 

moral of this post.  KEEP EVERY SUB FRAME THAT YOU TAKE, GOOD, BAD OR UGLY

[edarter]

Oh they wouldn't get deleted I can assure you, I'm just like you have described with normal photographs so I'm sure I will be the same with astro ones! Whether they get used again is another matter but they will be there waiting just in case!

Intersection alignment has helped but lines are still there. Not had a chance yet to see if I can work out if / how this can be sorted in post processing.

Thanks

Ed