Aligning different channels

[Haggis]

Last year I bought a used Atik CCD camera and yesterday I made my very first CCD imaging test shots.

I use Atik Artemis capture software and as a test I took 2 x 300 sec. shots in Luminance, then 2 300 sec. shots in Red, then Green, etc. so I ended up with 8 300sec .fit files. In Deep Sky Stacker I stacked the 2 Luminance files,
then I stacked the 2 Red files, etc. I just wanted a quick test so I didn't use any calibration frames. I combined the files into a RGB image in Photoshop and then noticed the colors are
all messed up probably because the stars on each stacked channel aren't exactly aligned. So I did some research and it seems you can use software to first align every channel so they won't cause those
weird colors in Photoshop.

Is there any free software I can use for this? On this website I read good things about "Registar" but it's not cheap. I also read Pixinsight and CCD stacker can do this but they cost even more.
Of course, Pixinsight offers an entire suite of tools but right now I'm only looking at aligning the different channels so that they are all equal before working with them in Photoshop.
I am willing to spend some money but preferably below 100 dollars. Can anyone recommend decent free or affordable alignment software?

Or did I miss something and can Deep Sky Stacker do this?

Thanks!

 

[Tinker1947]

"Gimp" is a free download.....

https://www.gimp.org/downloads/

[Andy Mitchell]

This is how I've done it, but I hope someone knows an easier way...

Load all your red light frames, right click on one and set it as the reference frame. Make a note of which frame you used. Add darks etc, and stack. Make sure the stacking mode is set to "standard". Save the final result. The trick is when you do green and blue, to also add the red reference frame we used earlier, and set again as the reference frame. Uncheck it though, so it isn't actually stacked. At the end you should have nicely aligned red, green and blue images. You can combine these in GIMP.

Or, have a play with atik's dawn program, its probably still considered experimental mind and it seemed a bit flaky when I tried it. Seems to be fairly good at stacking and merging colour channels, but not so good at rejecting bad frames before stacking.

 

[Waldemar]

Deep Sky Stacker: http://deepskystacker.free.fr/english/download.htm

tutorial: http://www.budgetastro.net/deep-sky-stacker.html

[Haggis]

Thank you very much Tinker and Andy.

I just installed Gimp now and will take a look at it. I really like the workflow you describe Andy, sounds simple and it should work with the tools I already have. Before trying to learn a completely new program, I'll give this a try first!

[Haggis]

Thanks for the link to the video tutorials, Waldemar. Much appreciated.