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Help combining LRGB images please.


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After much (educational and enjoyable) messing about I have now got EQDIR, Astrotortilla, PHD, APT, Stellarium, Stellarium Scope,  etc all working wonderfully and 'tuned' to perfection (well nearly!!) and working well all at the same time.

Thanks to help from this forum I have now stacked the red, green, blue and luminance FITS and I am now the very proud owner of my very first set of 16 bit tiffs - 1 x lum, 1 x red, 1 x green and 1 x blue and they look to have tons of detail in them !!!!

Question is what next ?????  (It was so much easier with a DSLR!!!)

I know I have to combine them but how - any suggestions for tutorials, books, web sites etc ????  I have played in PS but got nowhere fast.

Thanks in advance.

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Before you can stack the RGB (and L)  channels together they must be 'registered' with each other, a process which aligns using the stars as reference points for each frame. I'm uncertain if there is any free software that will do this, but I use either AstroArt 5 (first choice) or PixInsight. Using AstroArt as an example, the RGB channels are first composited together, then an LRGB can be created if a luminance channel is available by adding it to the RGB composite in a one-step operation. You can use photoshop to composite the channels but they must have been registered first. Maybe someone will come along and describe how to do the whole job in Photoshop but to be honest I think it will make life a lot easier if you equip yourself with dedicated software tools. PixInsight will do the whole thing - registering, calibrating, stacking in one pass using an automation script.

ChrisH

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After much (educational and enjoyable) messing about I have now got EQDIR, Astrotortilla, PHD, APT, Stellarium, Stellarium Scope,  etc all working wonderfully and 'tuned' to perfection (well nearly!!) and working well all at the same time.

Thanks to help from this forum I have now stacked the red, green, blue and luminance FITS and I am now the very proud owner of my very first set of 16 bit tiffs - 1 x lum, 1 x red, 1 x green and 1 x blue and they look to have tons of detail in them !!!!

Question is what next ?????  (It was so much easier with a DSLR!!!)

I know I have to combine them but how - any suggestions for tutorials, books, web sites etc ????  I have played in PS but got nowhere fast.

Thanks in advance.

Chris is correct, the registration of the frames to each other is essential and it all depends on which software you are using. There is a way of doing it manually in PS but is long winded . I use Pixinsight to do the whole lot. I thinthat I also managed to do it in DSS but the result was not great . If you wish I could tell how to do it but the end result depends on how well your guiding was.

A.G

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I use Registar to register the image files before bringing them into PS. It only does that one job, but it is incredibly easy and gives very good alignments.

[F2] click OK -> [F8] click OK -> File,  Save All. That's pretty much it.

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I register my channels in DSS this way:

I choose a good luminance sub, and in the list at the bottom if you right click on that sub a menu comes up and you then click "use as reference". It should then have an asterisk next to it.

Next load your say your blue frames and check the whole list. Register them but make sure you uncheck "stack after registering", once that's done uncheck the luminance sub in the list and just stack the blue frames. They should've all aligned with the luminance sub in the previous step.

At the end you'll get your "master" blue TIF to use in Photoshop, all's left to do is align your red and greens to the same luminance ref frame and then merge your channels in Photoshop.

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