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Western Veil Nebula - Feeling a little underwelmed and overprocessed


Grant93
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Hello everyone.

Decided to try and image the western veil a couple of nights ago, got just under 4 hours of data. And I just cant seem to crack it. I feel all of my current photos to date have often been quite grainy, cropped and uncropped. From the Andromeda which was hardly cropped, to this, which is cropped more than I wanted to something unusual going on in DSS which I can't figure out.

First issue, the image DSS keeps producing has a lot of star trails at the top, but non at the bottom, this is being caused some how by the first nights data, as when I only stack the second night, this doesn't happen. But I don't wanna throw the data away, as I am trying to bring out as much nebulosity as possible, just to practice processing. I have scanned all through the first nights. But due to this I have had to crop it more than I wanted. I will upload the original TIFF so you can see for yourselves

Second issue is one I can't get away from on any picture, it always looks grainy, overprocessed, and just unrealistic, like a cartoon, not matter how much I seem to crop. How do I get away from this?

Anyhow here it is, Tell me what you think.

Around 3 hours and 45minutes Lights @ 45 seconds each @ 1600 ISO.

25 Flats

25 Dark Flats

40 Darks

40 Bias

EOS800D

ZS61

SGP

VEIL5FIRSTEDITG.png

VEIL5.TIF

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My first reaction when I saw this was that it was produced by a stock DSLR. Most emission nebulae are Ha heavy, so to make the most out of your limited exposure time you will need to astro mod your 800D.

When stacking always reject those subframes with irregular star shapes if you want perfect result. Keeping them in will only deteriorate the overall quality of your image.

Do you dither while guiding? Dithering helps remove walking noise in the image. Also un-cooled DSLRs have higher read noise and dark current than TEC cooled astro cam, so the result is always going to be a bit more noisy. When processing make sure multiple curves are streched little at a time and don't oversharpen or else the end result may be grainy and contain banding.

Edited by KP82
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I *think* the double star issue at the top of the frame might go away if you delete all the text files in the folders which contain your lights for DSS and then try re-stacking.

I have had a go at your data using StarTools and agree with KP82 above: there's very little Ha signal.  Unfortunately there's also quite a lot of light pollution and a gradient which on a very quick run through I didn't eliminate.

Here's what came out:

VEILprocd.thumb.jpg.d0e5cfa9ea64400b6037a1528d753c9f.jpg

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I had a quick go in PixInsight and I see what you mean about the stars at the top of he image.

I left some of them in the image because you have captured some nebulosity in the top right of the image from another part of the Veil.

The image isn't that noisy and I was able to stop any graininess with noise reduction. There is quite a large amount of, what may be light pollution, centre left which could be cropped out or dealt  with in other ways. I have also reduced the stars in this one, so the nebula stands out better. ;)

As the others have said, the Veil is a predominantly Ha & OIII emission nebula so the red Ha will be difficult to pick up with a standard DLSR. It can be done with more data but you won't get anywhere near what you can see with a modified DSLR which has had the IR filter removed. You have good star colour and (apart from the top) the stars are nice and round. 

VEIL5.png.57abfaf6bc6249a1b06640fcf59d00bd.png  

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Just to add to what has already been said. 3hr 45m is not that long for a nebula. I took 4 1/2 hours with an astro camera (ASI1600mm pro) and my image was still noisy. I added another 6 hours data earlier in the week which made all the difference. I was doing narrowband which will help, but I think more integration time would really improve the SNR.

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6 hours ago, KP82 said:

My first reaction when I saw this was that it was produced by a stock DSLR. Most emission nebulae are Ha heavy, so to make the most out of your limited exposure time you will need to astro mod your 800D.

When stacking always reject those subframes with irregular star shapes if you want perfect result. Keeping them in will only deteriorate the overall quality of your image.

Do you dither while guiding? Dithering helps remove walking noise in the image. Also un-cooled DSLRs have higher read noise and dark current than TEC cooled astro cam, so the result is always going to be a bit more noisy. When processing make sure multiple curves are streched little at a time and don't oversharpen or else the end result may be grainy and contain banding.

Yea a modded camera is something I've wanted.. Don't want to fork out the money for an Astro camera with a decent sized sensor, as I understand you have to spend above a grand for something with a decent sized sensor. But I am getting a modded camera this weekend, been reluctant to mod mine as I use it for daytime aswell.  But I am looking forward to being able to experiment more with HA targets, and can still use my 800D for reflection nebula. Not gotten into guiding yet, so I have not been able to dither. As usual tried starting this hobby as cheap as possible, now wanting more and more things, such as a guiding set up haha. But thank you for the advice!

5 hours ago, almcl said:

I *think* the double star issue at the top of the frame might go away if you delete all the text files in the folders which contain your lights for DSS and then try re-stacking.

I have had a go at your data using StarTools and agree with KP82 above: there's very little Ha signal.  Unfortunately there's also quite a lot of light pollution and a gradient which on a very quick run through I didn't eliminate.

Here's what came out:

 

Thanks for the effort! Its considerably better than mine :D But arent the text files created when stacking in DSS anyhow?

4 hours ago, Budgie1 said:

I had a quick go in PixInsight and I see what you mean about the stars at the top of he image.

I left some of them in the image because you have captured some nebulosity in the top right of the image from another part of the Veil.

The image isn't that noisy and I was able to stop any graininess with noise reduction. There is quite a large amount of, what may be light pollution, centre left which could be cropped out or dealt  with in other ways. I have also reduced the stars in this one, so the nebula stands out better. ;)

As the others have said, the Veil is a predominantly Ha & OIII emission nebula so the red Ha will be difficult to pick up with a standard DLSR. It can be done with more data but you won't get anywhere near what you can see with a modified DSLR which has had the IR filter removed. You have good star colour and (apart from the top) the stars are nice and round. 

 

 

Thanks for that :D Didnt even notice the light pollution before cropping!

34 minutes ago, Clarkey said:

Just to add to what has already been said. 3hr 45m is not that long for a nebula. I took 4 1/2 hours with an astro camera (ASI1600mm pro) and my image was still noisy. I added another 6 hours data earlier in the week which made all the difference. I was doing narrowband which will help, but I think more integration time would really improve the SNR.

Have you uploaded it? I wanna see :D

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As requested. Needs a little bit of a processing tweek, but I quite like the result. Luminance plus SHO.

I had an issue with the auto focus so it is not as pin-sharp as I would like. Live and learn.....

 

Western Veil ST AP HSO Crop (1).jpg

Edited by Clarkey
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1 hour ago, Grant93 said:

 But arent the text files created when stacking in DSS anyhow?

Yes they are, but if you stack one night's data and then add another, later set, with a different rotation and  displacement DSS gets confused and produces the double star result,  DSS won't necessarily recalculate the registration settings unless the appropriate box is checked.

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