Iris Nebula (Caldwell 4, LBN 487)

[x6gas]

I've managed to bag two Caldwell objects this week with the rare combination of clear skies and a new moon.  This is the Iris Nebula in Cepheus.

I had fun processing this, so I hope it looks OK.  A night's worth of subs - R: 26 x 300s; G: 24 x 300s; B 24 x 300s - and I actually combined the lot to produce a false luminance.  I am actually not sure if I'd have been better shooting less RGB and a bunch of luminance instead...

Scope: TS Optics 130 super apo

Mount: iOptron CEM60 EC

Camera: Atik 490ex

Guiding: Atik OAG, QHY5L II, PHD2

Thanks for looking! Comments and suggestions, as always, very welcome.

Clear skies, Ian

[ChrisLX200]

Good detail, it's difficult to hold the core down as it's so bright. I would use something like SCNR to remove the green background to leave it a more neutral colour...?

ChrisH

[Martin-Devon]

This looks good Ian, on the full scale view I'm impressed especially by the star quality and how you've retained this through the processing - this was a really nice feature also of the lovely Cocoon nebula you posted recently as well. There's nice contrast & depth to the core as well.

Areas to play with - possibly push the star colour a bit more, it looks a little weak, and yes, possibly there is a slight green hue to the background and a little zapping as Chris has mentioned would sort that out.

Great to see your mount is on song now though, this is the 2nd image in a row that's been top drawer from you. Looks very promising.

Martin

[x6gas]

Thanks Chris, thanks Martin.

I did try running this through HLVG but I didn't like what came out the other end.  Instead I've just tried gradient xterminator and that seems to have cleared things up a bit.

Yeah I think you're right about the star colour Martin.  I think I need to protect the stars with a mask and reprocess as it's the luminance layer that's muting the colour but in the meantime I've done a Lab colour boost.

Thanks again for the comments!

[Martin-Devon]

Ian, have you tried processing without a luminence layer at all? I see some folk are now omitting the luminence now for the reasons that it often washes out the colour. As you suggest as well, the lab colour method, where lthe ayers are duplicated then blended down as soft light then colour (as nicely described recently by Olly) might be worth a try. You've dealt nicely with the slight green hue now though, it's certainly improved the image. It's a darn good image though Ian, don't lose sight of that!

Martin 

[x6gas]

Thanks Martin - I've sneakily upped the colour while you weren't looking  .

This was just a crude lab adjustment but I'll look up the description from Olly that you've mentioned - thanks for the tip!

I originally processed this as RGB only (as I did with the Cocoon) but the dark dust around the nebula doesn't show very well without the luminance.

Yes the new mount is performing nicely now and I'm very impressed with the TS130 too...

Thanks again for the comments.