Hardware or software artefact?

[D4N]

I have seen some weird glows on some of my images, I'm not really sure what is going on and I'm not convinced that there is really anything there.

They show up when I capture using Nebulosity as glows in the top corners. The longer the exposure the bigger the glow, after 5mins they are clearly visible without stretching.

Closing Nebulosity and opening Artemis capture I see nothing there then when I go back to Nebulosity they may or may not have gone.

I have never seen these in Artemis capture, only in Nebulosity.

I have seen them on darks as well as light frames.

The darks were taken with the cameras metal lens cap in place so the chance of a light leak is remote.

Does anyone know what's going on here?

/Dan

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[D4N]

Oops I forgot to mention that the camera is an Atik One 9.

/Dan

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[MarsG76]

It might be sensor AMP glow, I've seen this in my 300D, but not as bad. Is your cooling working? Apparently heat build up makes it worse.

[Steve Ward]

'Leaky' filter wheel ... ?

[D4N]

The cooling is working and reports -20C.

I thought amp glow at first but I don't understand why it would go away when the temperature remains the same.

The filter wheel is internal to the camera so I don't think it can be that.

/Dan

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[Thalestris24]

Hi Dan

I'm afraid I don't know anything about your Atik, but there were once amp glo problems with the qhy8l. It only showed up in one corner but the problem was much improved with a new driver but still dependent on exposure length. Maybe an idea to take some darks (in the dark!) with the camera cap on and wrapped in foil (if possible) to eliminate the possibility of light leaks? 

Hope you can sort it.

Louise

[swag72]

This immediately made me think of the 'Sony Glow' issue that affected some QSI camera's with the same sensor. As the exposures lengthened, so the glow got worse. It was calibrated out with darks (that also showed the glow). Also to my knowledge, and there was quite a thread on CN about it, Atik and SX weren't affected.

What makes me a little unsure about it being a hardware issue is that you say that in Artemis you don't see it but in Nebulosity you do. Perhaps one programme does more of a stretch than another? If it is indeed a sensor issue then I'd expect it to show up the same regardless of the software used.

I'm just thinking out loud really ....

[D4N]

I thought about that but since I stack in Nebulosity all of the frames end up there so it can't be how Nebulosity is displaying them.

There is also the fact that it can be seen in linear long exposures.

I also get good subs in Nebulosity, I don't know how that happens.

I suspect some sort of driver issue at the moment, perhaps Artemis communicates differently with the camera than Nebulosity.

/Dan

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[ollypenrice]

I think this is an issue with Nebulosity. A bit of advice I had from Ian King many years ago was, 'If a product misbehaves, run it in its own software.' I think it's very good advice. I use Nebulosity and Artemis side by side on our 'tandem' because one side is Mac rather than PC. Quite honestly, give me Artemis any day. It wins handsomely on all counts for me.

Olly

[D4N]

Thanks Olly, I have Artemis chugging away on a sequence right now.

I like the focusing tool in Nebulosity, especially as it is able to control my focuser from within the program. I guess I can still use that but I need to swap programs to do it.

/Dan

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[opticalpath]

When you view an image in Nebulosity, then in Artemis, are you sure that the two programs (when viewing images) are not applying different default stretches, with one revealing the 'glow' and the other hiding it?  I would save one of the Artemis-captured images that doesn't show the glow and take an independent look at it in Photoshop or some other program; give it a good stretch there to confirm that the glow really is absent.

Adrian

[D4N]

I open up all of the Artemis images in Nebulosity for stacking so I know there is no glow on them.

There is also no glow in the final image and I am not using darks or flats.

I have viewed them without the auto stretch as well and it is still visible in the Nebulosity images that have it and are long exposure.

/Dan

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