first try M17 anf HCG63a

[muletopia]

Hello Folks,
A pair of poor picturs put up in the spirit Alex suggested.
My first ever Hickson object attempt.
Gear
Canon 60Da at prime focus of uncorrected Mewlon 210
Mount: Mesu mount 200 permanent pier mounted in a Sirius 3.2M dome.
Telescope control Sidereal Technology
Go to M17 Cartes de ciel
HCG 63 electronic setting circle equivalent in Sitech


Camera control Nebulosity 3
Guiding PHD2

M17 35 2 minute exposures at ISO 800 (guiding rms about .6 arc seconds)

HCG63 5 16 minute exposures at ISO 800 (guiding rms about .28 arc seconds)



Processing
dark subtraction and stacking Siril
Stretching Nebulosity 3.


There, I think that is all.


Opinions welcome,
Cheers
Chris

[muletopia]

I read M&T's comments about failed liver transplant images of this object so I tried toning the red down. But a green background remains, how can I get rid of the green?


Chris

[xelasnave]

Nice work.I can't see the green..but then I am colour blind.
You can manipulate colour various ways but one I like is in photo shop make a solid colour layer of your desired colour..put your image on top and use the rubber tool ever so gently where you want your chosen colour..it's a hint of course ...not proper but I hope you can use it when all else fails..you could manipulate a copy image in hue etc until the green changes to what you want and do similar with the rubber tool.
You certainly have a nice set up.
Thanks for joining in...and it's a great image you can be very proud...make sure you keep a copy on your phone so you can show complete strangers in the shopping centre.

Alex

[RyanJones]

Hi Chris,

I know nothing of Nebulosity so I can’t point you in a specific direction however I’ll tell you how I do it in Photoshop and see if you can translate it.

The green is there because you’ve globally reduced the intensity of the red channel. This means that your image is no longer white balanced. One of the first things I do is globally correct the balance. I set an eye dropper somewhere in the image that I know is black ( without stars or nebulosity) and I balance the RGB channels. After that if I want to change the luminance of any given channel locally in the target I use colour range selection and adjust the intensity to select the only the target. This way you can then use saturation or brightness adjustments without affecting the rest of the balance in the image.

I hope this makes enough sense and that you can translate it to your software.

Cheers

[muletopia]

Thanks Ryan,
I don't know if your ideas can be translated to Nebulosity but I will have a good look,
The only other image editor I have is Gimp, and that may be a better bet for your approach.


Chris


PS

in my setup description I did not mention that the ob is solar powered, 100 watt panel charging a 135 AH AGM battery. So 12 volt and also 240 V AC from an inverter to power a laptop are available in the ob.