Alignment of images in RGB

[Imd]

I was pulling my hair out last night and while I have a few strands left I wonder if I could seek some advice from some of you more experienced Mono astrophotographers.

I have captured my first images in LRGB and I have all my calibration frames for each filter. I have taken the images over a couple of nights, I don't have many subs because the clouds rolled in, and there have been meridian flips whilst imaging.

I have registered and stacked in DSS. Each image comes out ok and aligned with each of the subs for each filter but the RGB images output from DSS are ever so slightly misaligned with eachother.

Is the misalignment of images for each filter after stacking expected and is it then a manual activity to correct in Photoshop or did I miss a really useful step in DSS?

Thanks for looking

Ian

 

[Freddie]

Did you use the same reference sub for each of the 4 stacks?

[MarkAR]

Just what I was going to ask. You need to use the same reference image, say one of the L's for every filter. 

[Imd]

This sounds like the answer I need.:) I thought it might be something like that. I didn't use the same reference image for all filters. I just need a little more detail please.

Should I select a single reference image eg a LUM with best score even though Im stacking red, green or blue?

I have attached blue and green channels to illustrate my problem

[Tommohawk]

Do your first stack, say LUM...  the sub with the highest score is used for reference. Keep that one, remove all the others, then load your next lot, say RED. Make sure you mark the LUM sub as reference - I think you can right click for this, and it will be asterisked to show its to be used as reference...

BUT untick it in the first box to prevent it being used in the stack. Then same for G and B

[Richie092]

yes, just don't tick it and it wont get included in the stacking.

[Tommohawk]

Just now, Richie092 said:

yes, just don't tick it and it wont get included in the stacking.

SNAP

[Imd]

Thanks everyone. I have used the single reference image for all filters and its nicely aligned. - phew!!

 

Ian

 

[Ouroboros]

I don’t do LRGB but this question has occurred to me. So thanks, very interesting to see how it’s done. 

[Tommohawk]

... or use Astropixel processor which does all this for you in one go.... See Stargazine 12 on Sunday for further details.

(PS I'm not on commission!)