Great Carina Nebula (NGC3372)

[SpaceNoob (Chris)]

Hi All,

I have posted a previous version of this image quite a few months ago, as time has gone by, my processing abilities are improving ever so slowly as I learn a little more.

This is my latest attempt at trying to push what I can out of this great patch of sky.

Composition is HaR(Ha)GB with data being collected from an FSQ106EDXIII and SBIG STT-8300M.

Higher res on astrobin.

Massive full res

Cheers,

Chris.

[RickS (Rick)]

Nice work, Chris.

[Larryp (Laurie)]

Very nice!

[gregbradley]

A lovely image there Chris. I would recommend the HLVG plug in from
Andrea Rogelio (free) for Photoshop. That would get rid of the green cast that often occurs in dark site images from sky glow. It throws off the colour balance a bit.

Greg.

[SpaceNoob (Chris)]

Originally Posted by gregbradley

A lovely image there Chris. I would recommend the HLVG plug in from
Andrea Rogelio (free) for Photoshop. That would get rid of the green cast that often occurs in dark site images from sky glow. It throws off the colour balance a bit.

Greg.

Cheers for the feedback Greg, much appreciated. I have tried importing the plugin to CS6 on OSX, but can't seem to get it to load. Will try this out again tonight. I have read that it is based on a PixInsight routine, I'll have a fiddle with the SCNR Average Neutral algorithm that Andrea Rogelio mentions on his website, wherever it is buried within PixInsight.

I don't use a dark site, just my backyard here in Canberra, will this still pick up the skyglow? The green subs did have very large signal, but I figured this was a property of the target.
I can't really see the green tinge, but this doesn't surprise me, its either my untrained eye or my colour blindness. Colour balance is definitely one part of processing that I really struggle with.

Originally Posted by Larryp

Very nice!

Thanks Laurie

Originally Posted by RickS

Nice work, Chris.

Thanks Rick

[SpaceNoob (Chris)]

Aha!

Found it, SCNR within pixinsight makes a difference, looks far more neutral.

Thanks!

[gregbradley]

Chris, the green cast is most likely light pollution which often seems worst in the green channel. Air glow would still be present but probably a minor component.

Once corrected the blues should come out more and perhaps some magentas. It can sometimes swing the colour balance too much to magenta requiring a tad of correction there as well. It also corrects the yellows which become more yellow and less yellow/green.

I see green colour casts sometimes in my images from my dark site which has almost no light pollution. It used to puzzle me until I started doing some widefield DSLR imaging and got to see just how much and how often there is a green airglow. Usually though its the bottom 15 degrees of sky that has it.

Greg.