M20 - Trifid

[whzzz28]

Reprocess of some M20 data i had.

Not happy with the stars. Blue stars have a much larger halo then others. All i can think of is that the blue filters focus is a lot further off than any other filter compared to luminance. Oh and stars are blown out. Guessing 25k well depth and 10min subs will do that.

Stars aside, i'm happy with my attempt at processing this.
ACDNR works well, but softens the image.

Full image: http://core-au.net/astro/M20/final1.jpg
(Warning: 6mb)

I may have gone a bit too overboard with saturation during LRGB combination. I have been finding though that my images appear on other monitors lacking in saturation, so it may just be me.
My work laptop, and work screen both show this differently to my home machine. :rolleyes:

Comments are welcomed.

About 2 hours of data, 10min subs, taken from the Brisbane 'burbs.

[alpal]

That's looking very nice indeed.
It would be good to try & process out the blue halos on some stars
for a perfect picture.
By the way - what are the camera, telescope, mount & guiding details?
Do you have a picture of your setup?

[RickS]

Nathan,

I once had the same problem and it took me a while to find the solution... colour management. The JPG file you posted has a colour profile of "Dell U2410 Color Profile,D6500" which I'd guess is your monitor? You need to set up PI to work in an independent colour space with a reasonably wide gamut, say Adobe RGB or ProPhoto RGB. Then when you're finished processing and producing a JPG file you can use AssignICCProfile to give it a sRGB profile. sRGB is a lowest common denominator color profile that will give OK results on crappy monitors and with non colour managed applications (like many web browsers). Oh, and if you're not working on a calibrated monitor you really should be!

Cheers,
Rick.

[whzzz28]

I tried doing a blue channel star mask and then a morphological transformation but the results were pretty bad. I'll have to do some more reading.

The scope was an ED127 refractor. QHY mono camera on an EQ6 with an ED80 + lodestar for guiding.

If I remember correctly, this is:
2x red
2x blue
1x green
and 5x lum
All 10min subs.
Had plans for 7hours worth of data but only got the above before it clouded over for the night.

[alpal]

Thanks for the details.
You still did well & I know that processing can be difficult.
That was a QHY9 camera with a cropped frame?

[whzzz28]

Yes it is slightly cropped to remove stacking problems.

[RickS]

Sorry, it's ICCProfileTransformation, not AssignICCProfile.

[whzzz28]

Yeah i had a play with it last night. Seems to be much more consistent now, except for the terrible screen on my laptop.

Cheers.

[whzzz28]

This should look a bit better.

[strongmanmike]

Hi Nathan

That's a great M20.

Good colours, nice blend of blues, greens and whites in the transition zone between HII and the reflection neb there.

Mike