Widefield NGC6188

[ChrisV]

I captured this last month, rokinon 135mm lens on an ASI071 camera. Using the STC duo filter. No matter how I process it I'm getting green in the lower left -is this reality or just artefact/fantasy?

Higher res here
https://www.astrobin.com/403050/

[doppler]

I think it's real , google it and compare the images you see.

[gregbradley]

No I think its an artefact. Probably something to do with the filter.
Is it a light pollution filter?

Greg.

[RyanJones]

Beautiful wide field Chris. I'm not sure if the green/blue is supposed to be there but I would argue that it looks good like that. You've got it scattered on the right too but less dense but I like the colour combination.

[ChrisV]

Thanks all. I've seen the green in some shots of the area but not others.
It's a kind of an LP filter Greg - it has 15nm passbands at Ha and OIII.

[topheart]

Hi Chris,
Nice filed of view. I'm not sure about the green. Great detail.
Cheers,
Tim

[Atmos]

It is a nice field Chris :)
As for the teal, it’s not real as it should be a browny golden due to the star colours in that area. It’s an artefact of the filter you’re using. You’d end up with something similar using a Ha and OIII filter and doing a HOO image I’d imagine. Nothing you can do about it without adding in unfiltered RGB data :)

[ChrisV]

Thanks Colin. Sounds about right. If I process as an OSC image it's fine.

But I've been trying to process these using a narrow band approach. I think it's probably the crappy star masks I make and the star removal. I'm struggling with this a bit. Now I look at it I can see that I'm not masking/removing a while bunch of small stars which are much brighter in OIII.

[Atmos]

The only way you'll be able to get rid of the teal and achieve what you're after is to take data with both the filter and unfiltered. The duo filter would be used as a nebula enhancement to the RGB data which presumably is going to be under light pollution.

[AG Hybrid]

Cool Picture.



How did it manage that with a 16MP camera?

[ChrisV]

I didn't notice that on the astrobin. It's dithered and drizzled. And it actually helped resolve things a bit better. I must go back and fix up the false green now