Omega Centauri

[traveller (Bo)]

Last one of the lot from the weekend.
Omega Centauri
50 subs of 60 seconds each at 1600 ISO.
I think I may have over processed it slightly
Bo

[blink138 (Pat)]

is there a bigger pic bo, it looks like it right down to the core!
i think it is too red
pat

[traveller (Bo)]

This is the uncropped version. I also toned down the colouring and cut back on the black clipping a bit.
I think it looks better now.
Bo

[Somnium (Aidan)]

Looks better Bo. Just wondering if you took flats for this one, the light pattern looks very similar in your m42. You might be able to remove this

[traveller (Bo)]

No flats Aidan,
I will take them and add them to re-process.
Bo

[rustigsmed (Russell)]

hi bo,

you will need to have the camera aligned as it was when attached to the scope.

I hope you don't mind, i've done a synthetic flat and subtracted it from the pic.

this can be done on globs and galaxies usually and is muh harder on nebula as its hard to know where the gradient is exactly. so definitely look into flat acquisition - it is way better. it improves images more than any other calibration technique as far as i'm concerned.

2 copies opened in PS, one copy dust and scratches to fuzz out stars.
clone tool used to guestimate what the gradient would be doing over the bright glob area.
apply gaussian blur to smooth out clone tool hard edges (over entire image).
go to the original pic, go to apply image (then select the blurred image to apply), then choose subtract mode (offset around 15-20 and i used 100% subraction).

have attached the resultant version and the artificial flat. (it often does weird things at the edges unfortunately).

cheers

rusty

[raymo]

What is the cause of the greenish area below O. Cent?
raymo

[traveller (Bo)]

Thanks Russ, I really need to learn how to stack and process properly, still very much a hack at the moment
Raymo, the light glow at the bottom is light pollution. I live 9.5 km from Melbourne CBD and did not use a LP filter
Bo

[Somnium (Aidan)]

Originally Posted by rustigsmed

hi bo,

you will need to have the camera aligned as it was when attached to the scope.

I hope you don't mind, i've done a synthetic flat and subtracted it from the pic.

this can be done on globs and galaxies usually and is muh harder on nebula as its hard to know where the gradient is exactly. so definitely look into flat acquisition - it is way better. it improves images more than any other calibration technique as far as i'm concerned.

2 copies opened in PS, one copy dust and scratches to fuzz out stars.
clone tool used to guestimate what the gradient would be doing over the bright glob area.
apply gaussian blur to smooth out clone tool hard edges (over entire image).
go to the original pic, go to apply image (then select the blurred image to apply), then choose subtract mode (offset around 15-20 and i used 100% subraction).

have attached the resultant version and the artificial flat. (it often does weird things at the edges unfortunately).

cheers

rusty

Hi Rusty, that sounds like a really interesting technique . Can you outline the exact steps, I am having trouble trying to do it and I would love to give it a go

Thanks

[rustigsmed (Russell)]

I have created a quick youtube video quickly showing the same technique on one of Aidan's Luminance shots.
https://www.youtube.com/watch?v=GW67PwUP8Ww
usually i would take more care with the clone tool but it does the job.

Cheers

Rusty