light pollution help

[HunterHarling]

Hello all,

I have never had light pollution problems before hyperstar, but now all of my images have green in them that appears to be light pollution. I cannot remove it without losing lots of my nebula/galaxy that i am imaging even when i use light pollution removal in Photoshop and set the radius to 55 pixels. I am beginning to wonder if it is my nightscape camera doing something wired as i have had one problem after another with it. Also, it dosn't seem like much light pollution where i live because i can see to 6th magnitude and easily see the milkymay.

[Victor Boesen]

do you have the raw file?

[Ibbo!]

Maybe this could help

http://www.deepskycolors.com/tools.html

[almcl]

What camera and scope are you using?  

Also how are you post processing?  

Do you use flats?  There seems to be quite a lot of vignetting, although it may be something else.  

[HunterHarling]

I have tried something similar to removing the green and I am left with the same thing but grey instead of green... Do you have to pay for the plugin or is it free?

I'm using the nightscape 10100 ccd with c8 and hyperstar. I'm stacking and calibrating in dss and post processing in Photoshop and Lightroom. I didn't use flats for this one but I usually do.

I'm going to find the raw version of my image. Do any of you think it could be the camera?

Thanks for the replies.

[geordie85]

I use gradient xterminator that is really really good at removing gradients. 

You can use the free trial to see how you get on with it. It will also colour balance your background aswell which may (or may not) remove the green tinge. 

[almcl]

If you didn't use flats, then I think it could be vignetting.  

Try stacking it with some older ones (if you have some) and see if it improves matters.  There is some walking noise/hot pixels and also some vertical banding visible, but there's something decidedly strange about the colours in the jpeg you posted - predominantly green in the centre and blue and red in the outer regions.  

Not familiar with the camera so can't comment on that, but wonder if somewhere in the processing trail the data got 'adjusted'?

[HunterHarling]

I'm going to try gradient xterminator it does look good...

The colors are weird because I wasn't using dss right but it even with the right colors there's still green. Could vignetting really do this? I know vignetting makes the edges darker but if never heard of in being green??

Hopefully gradient xterminater helps.

[Mick J]

Do also try HLVG as per Ibbo's post above, it's a free plugin for photoshop, donate if you like, instructions on this page

 

[HunterHarling]

I couldn't download gradient xterminator because it's only for Photoshop cs4 and higher and I have cs2. I tried downloading HLVG but it seems Photoshop didn't recognize it as a plugin. Can one of you have a go at removing the green yourself?

Thanks

[Knight of Clear Skies]

I agree with people that this looks like heavy vignetting, fast optics such as hyperstars often suffer from this but flats should do the trick. Taking a single flat and checking whether the falloff matches the image in the OP should confirm this.

[AKB]

Applying DBE-like and SCNR-like processing should yield you something like this.

Definitely a job for flats, though (and darks to get rid of those hot pixels.)

[carastro]

Quote

I couldn't download gradient xterminator because it's only for Photoshop cs4 and higher 

I have CS3 and can use gradient exterminator on that.  Maybe there is a different or earlier version download for CS3.  try speaking to the Author Russell Croman he is very helpful.  

Definitely looks like lack of flats to me, but can't comment on the green colour.  

Carole

[HunterHarling]

Wow. That looks like dbe works well. Were you using pixinsight? Tonight I will get new data with some flats and see if it helps. I will definitely talk to Russell Croman.

Thanks

[AKB]

16 minutes ago, HunterHarling said:

Were you using pixinsight?

No, I don't use it, or PS, or APP, ...  but this is my 'equivalent' (actually, more like ABE, since in this case there's no manual placement of points as it can find its own) programmed in MATLAB, which I have and have used for decades, so I know it quite well. 

[ollypenrice]

You need to take flats. If you don't, you are wasting your time, especially with a Hyperstar. You can bash the data about in software as much as you like but if the data isn't calibrated it will be bad data. Sure, I use DBE and SCNR green but I always take flats becaue they are non-software and because they are incredibly important.

Olly

[HunterHarling]

Ok, the flats did not help but I might not have taken them right. Does anyone know how to take good flats with hyperstar? Because I sure don't. Also, the cameras TEC cooling is supposed to get to 20 degrees below ambient but it never can keep it below 2.5 degrees above ambient so I am going to trade out this camera with a completely different camera. I am considering the qhy 10 and any thoughts on that would be appreciated

AKB- where can I get the software you used it looks really good.

Thanks for the help

[Pompey Monkey]

On 7/14/2017 at 19:28, HunterHarling said:

AKB- where can I get the software you used it looks really good.

Thanks for the help

Matlab starts from about £100 for a home user license*. Then you have to program it... I suspect that if you don't already know about what it is and how to program , then it will not be a good choice for your image processing.

Pixinsight costs about £200 for a license. It comes with a graphical interface, and all of the functions and utilities that you need to process your images built in. It's a steep learning curve, but nothing like learning Matlab from scratch.

And don't forget that you can get a subscription to Photoshop, which is equally as popular as Pixinsight, for about £9 a month.

Other image processing packages are available, but I have not used these and therefore can't add any useful comment.

*You might also need to buy one or more "toolkits" at £29 each to process images too, but I'm not sure.

[TareqPhoto]

I am new to this and not expert, but the image in your first post doesn't represent a light pollution, i have light pollution in my area and i never get something like that, i mean the light pollution will be shown into the entire frame or  it is coming from below of the frame, but not into circle in  center or middle of the frame, it is like the light pollution came from that object not from earth or your location, but as i said, i could be wrong and i am no expert.

Also you can tell if it is the camera until you try it again on same object or another one, if you still see that green then most likely it is the camera, try different factors so you can find out what caused that.

I really hope that i won't see many issues once i start to imaging DSO.

[HunterHarling]

I found out that the green was the nightscape camera. I got it exchanged for a qhy10 and there's no more green !!

Thanks for all the replies.

Hunter

[TareqPhoto]

Told ya 

[HunterHarling]

Thank you

[Stu Wilson]

Added GradientXterminator to your image and this came out

 

Stuie