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The 130pds rides again (IC1396 now in colour)

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Finally, enough dark/clear sky to get some OIII on this! :)

This time ive tested a little theory in regard to using binned OIII and combining that with unbinned Ha data. What I basically did was to match the scale of each image halfway (ie: resize the Ha lum by 75%, and the binned OIII by 150%) - that way the stars dont go all funny, and Ive only lost a small amount of resolution but its still enough for a detailed enough rendition.

Ive tried hard to stay away from a Ha red dominated version, so I had to do some creative stretching of the OIII data (of which there wasnt much!!) and back off with the saturation. As usual it could do with more OIII, but its not ideal trying to get it while it isnt astro dark (yet!).

Minimal cropping to remove stacking artefacts.


Ha 24x600 L, 8x600 Ha_R, 8x300 OIII_G&B (binned OIII)

130pds, Atik 383L+, NEQ6, MPCC MkIII

Calib: Flats and Bias

Setpoint: -15c

Thanks for looking :)


First the Ha layer:


Now the colour:



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Thanks guys :)

Im just wondering what to go for next, I'll probably stay in the general area or swing round and finish M16 if I get some clear stuff this weekend. Now Ive got the field sorted for this scope Im quite looking forward to the coming Astro season!

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130 PDS rule!  I sold mine to put funds towards the 65mm Quad and although I'm pleased with it, I do miss the old 130 PDS.  Cracking stuff!


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Beautiful Rob, Crispy and smooth all at he same time.

Well done,


Thanks Paul, the crispy is gotten with a high pass filter in Ps. Which is really quite useful due to reflector images not being quite as sharp as they would be with an ED refractor, so the high pass puts a bit of zing back into the image - but its easy to overcook if not careful or selective in how you apply it.

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Super image again Rob - the palette is just perfect

Thanks Martin, it took me a while to decide on which was the suitable colour scheme. My original plan of mixing some Ha with the OIII didnt quite work out (too much blue in the wrong places), so it was just case of part processing the OIII channel (with layer masked stars) before merging it with the Ha red channel.

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Very nice indeed Rob. Good trick with the resizing to match the binned and unbinned data.

Thanks Rob :) I thought the halfway method might be a good compromise considering the pixel size and sampling rate at 650mm when binned (3.4" p/p). To try and scale it up too far from there would have been messy, but one thing I learnt was to process first - then rescale. Doing it the other way round lead to artefacts on quite a few stars. Given the amount of pixels the 383 has in the first place, I guess a 25% hit on image scale isnt such a massive price to pay for getting a faster OIII channel together, but at the same time it allowed me to concentrate the effort into getting a good Ha luminance master (where most/all of the detail is carried).

But I think this method should only apply to OIII regions that do not carry structure, it wouldnt be suitable for stuff like the Veil were there are distinct Ha and OIII layers/components.

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