Elephants Trunk Help

[Anthonyexmouth]

Is this blueish area real or something to do with my optics or processing? Cant see it in anyone elses images. If it's me or my optics, how would I get rid of it. 

[vlaiv]

I think there is real OIII glow in that region.

If you look NB images of that region - you will see that it is mostly dominated by OIII (but this is due to processing, OIII is usually fainter than Ha in "normal" light as there is much less O vs Ha).

 

[Anthonyexmouth]

1 minute ago, vlaiv said:

I think there is real OIII glow in that region.

If you look NB images of that region - you will see that it is mostly dominated by OIII (but this is due to processing, OIII is usually fainter than Ha in "normal" light as there is much less O vs Ha).

 

Ah cool, so not anything i'm doing. Do you think that region is something a dual band filter might help with on a OSC or best to live with it and wait for another go when I move to mono. 

[vlaiv]

1 hour ago, Anthonyexmouth said:

Do you think that region is something a dual band filter might help with on a OSC or best to live with it and wait for another go when I move to mono. 

If you have one - then yes, give it a go. That is emission region and good dual band (or more bands) filter will eliminate sky glow / LP background and improve SNR substantially (if you have significant LP).

[Anthonyexmouth]

27 minutes ago, vlaiv said:

If you have one - then yes, give it a go. That is emission region and good dual band (or more bands) filter will eliminate sky glow / LP background and improve SNR substantially (if you have significant LP).

I dont have one at the moment,  hopefully picking up a Sharpstar 76 in a week or 2 and planning on pairing that with an asi533 mono but thought about keeping my 294 and maybe adding a dual band filter. 

[ollypenrice]

I agree with Vlaiv that there's real OIII in there. However, I think you may have a red-green gradient (red left, green right.) This is common on OSC data, I find. Compare the dust patches in the lower part of the image. Those on the right are distinctly green. What we can see of the background (top left and top right corners) also confirms a greener right hand side.

Lower levels of green will turn things magenta and that, too, might be going on just left of centre. 

What do you use to neutralize gradients? My guess is that Pixinsight's ABE would sort this out, and/ SCNR green.

Olly

[Anthonyexmouth]

11 minutes ago, ollypenrice said:

I agree with Vlaiv that there's real OIII in there. However, I think you may have a red-green gradient (red left, green right.) This is common on OSC data, I find. Compare the dust patches in the lower part of the image. Those on the right are distinctly green. What we can see of the background (top left and top right corners) also confirms a greener right hand side.

Lower levels of green will turn things magenta and that, too, might be going on just left of centre. 

What do you use to neutralize gradients? My guess is that Pixinsight's ABE would sort this out, and/ SCNR green.

Olly

I used DBE, is it worth running ABE too?

[ollypenrice]

3 hours ago, Anthonyexmouth said:

I used DBE, is it worth running ABE too?

What was your uncropped image? To do DBE you need background markers distributed across the frame. One in each corner would be a minimum, I think.  When I don't have that available I generally use ABE. This target tends to be full of nebulosity with dark sky conspicuosly absent!

I'd certainly try SCNR green as well.

Olly

[Anthonyexmouth]

2 hours ago, ollypenrice said:

What was your uncropped image? To do DBE you need background markers distributed across the frame. One in each corner would be a minimum, I think.  When I don't have that available I generally use ABE. This target tends to be full of nebulosity with dark sky conspicuosly absent!

I'd certainly try SCNR green as well.

Olly

Uncropped was a mess as it was a stack of 3 nights and a camera rotation i'd forgotten about, thats why its that shape. 

[ollypenrice]

27 minutes ago, Anthonyexmouth said:

Uncropped was a mess as it was a stack of 3 nights and a camera rotation i'd forgotten about, thats why its that shape. 

OK, if that's the full field, ABE might beat DBE. However, on this image I'd just try four DBE points as shown by the white dots.

Olly

 

Edited May 29, 2022 by ollypenrice
typo

[vlaiv]

1 hour ago, ollypenrice said:

shown by the white dots.

Using white dots to designate something in star field image? Maybe not the best idea ever

[ollypenrice]

1 hour ago, vlaiv said:

Using white dots to designate something in star field image? Maybe not the best idea ever

🤣   You'd have to be miles out of focus for those to be dots. They are circles.

OK, I called them dots.

Big dots - like circles...

😁lly

 

[tomato]

You would only mistake them for stars if they were in one of my oversampled images…😉

[gorann]

On 28/05/2022 at 16:54, Anthonyexmouth said:

I dont have one at the moment,  hopefully picking up a Sharpstar 76 in a week or 2 and planning on pairing that with an asi533 mono but thought about keeping my 294 and maybe adding a dual band filter. 

With a dual band filter and an OSC you can pick that Oiii up. This is what I got with an NBZ dual-band (Ha+Oiii) filter (RASA8 and ASI2600MC) even under a full moon which is generally not great for Oiii (but OK for Ha).

Cheers, Göran

[Anthonyexmouth]

ok,  different image now and a new try with PI, Got 7hr on the Iris nebula. Ive tried DBE and ABE. are those the tools to remove this green and purple blotches

Iris Processed.tif

[Budgie1]

If DBE & ABE aren't working then process it normally to a starless background, then you can use SCNR to remove the green cast (30% should do it). For the purple try Scripts > Utilities > CorrectMagentaStars and run it with default settings.  

Just running these two, quickly on your attached file does the job:

[Anthonyexmouth]

Awesome, thanks. I'll give that a go myself now.