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Hi all,

Not sure whether I am expecting too much but I chose to try M103 tonight given it has a number of very red stars in and around it.   I am using a 314L+ mono with filter wheel.  I took 5x120secs 1x1 for each of the 4 filters which I figured was plenty to capture the colours  (although L adds nothing as you can imagine).  I attach the picture below and as you can see there isn't the deep red you see in other images of M103 I have seen.  I popped each stacked master into the respective channel and aligned the best I could.

Am I expecting too much or have I gone wrong or missed a step?


Many thanks



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I think you would do better with more subs, and also play with the color saturation, below is your data with augmented saturation, it would probably look better if I had your Fits or Tiff file instead of the JPG



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1) If you're using an electric F/W check your fits headers in a programme which lets you do so in order to be sure that the filters used actually correspond with the colours channels as you have named them. Most of us have shot a load of 'red' through the green filter in the dead of night!

2) What programme did you use to combine the three colours? Were the three files correctly ascribed? Were settings like white balance checked?

3) In a programme like Photoshop where are the three histogram peaks relaitive to each other? A good rule of thumb is to align the top left of the histo peak in each colour by moving the black point.


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Thanks guys.

Had another go at combining (in photoshop) and got a better result, as below.  This time I combined before doing any level/curve adjustment etc. Is that the right way round?  

Olly - forgive me - on 2/ I simply cut and paste each coloured stack into the appropriate channel. Never even considered white balance. Do I need to?

What I have noticed however is that the stars on my red subs (andeven more so on the lums) are "bigger" then on the green and blue.  This creates red halos when you align as you can imagine.  Assuming the subs are in focus, why would the red/lum filter create larger stars and what can I do about that? Is it exposure time?

Appreciate you help!




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