Jacob Heppell:
Rick Veregin:
For sure, you can take your best Ha sub and covert to RGB in photoshop. The converted image will be your reference for the color images, the original sub will be the reference for all your mono subs. Or you can open your best color image sub exposure in Photoshop then convert and save it as a grayscale image. Use that grayscale image to register the mono images. Use the same color sub to reference all your color images. You don't need to convert a lot of images, just use one good sub exposure as your reference. Either will work, use your best image overall as the reference.
Exactly what I was going to suggest! Although I now use Registar for aligning because it does a better job than DSS.I
I use to use DSS to do that but it was difficult, sometimes would not register the images. So I calibrated and stacked all the color and Narrow band separated and then open each stack in PS to make sure the pixel density was the same, if not, then you need to resize it otherwise DSS won't register the stacks. Now, I just use Registar which is very powerful and you do not need to resize anything. It would even combine pictures taken with different FL and telescopes.