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Iris Nebula - a first attempt...


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Hello All, 

Very much a beginner to this hobby.  I got my first telescope last year but didn't have much chance to use it due to lack of clear skies :(  In the past I've been guilty of 'kid in a sweet shop' syndrome, imaging a bit of this and bit of that 😁  This year I wanted to try and focus on a project and try to do it well.  I've picked the Iris Nebula and I've started collecting data over the past couple of weeks.  I'm aiming to include about 15-20 hours of exposure time in the hope that this might bring out some more of the dust detail.  I am using Affiinity Photo for processing and DSS for stacking.  I've included my most recent process in the hope of getting some feedback and any words of wisdom.  This is 6 hours 28 minutes exposure time.   I had some issues in getting my guidiing set up so these exposures were not guided or dithered. Hopefully this issue will be resolved for my next imaging session.  I've found colour balance and noise to be the biggest challenges when processing.  I also think my focus could have been better.  Any advice for this target, processing or general wisdom for working on a project like this is much appreciated.  ✨

 

Skywatcher 80ED with 0.85 reducer flattener 

HEQ 5 (belt modified)

Canon 1200D (unmodified) 

ISO800

213 x 75s

122 x 60 s

30 x flats

100 x bias 

 

 

P5 S1S2FB.png

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I think the main comment I would make is to get your guiding and dithering set up as a priority. The data here looks pretty good, but for a relatively noisy DSLR you will always struggle a bit without dithering. There is very little evidence of walking noise which suggests your polar alignment and tracking is good too. With dithering enabled I suspect you would get a very good rendition of this without too much more integration time (depending on your skies etc).

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Thanks so much for your comment 😊  I'm encouraged that guiding and dithering will make a good difference to the noise level.  Hopefully PHD2 will work for me next time - I turned out to have a wrong guide rate setting in EQMOD. Thanks for the encouragement! 

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It's certainly a good first attempt for a short amount of time. I did it earlier this year over around a dozen sessions (20hrs+) but couldn't really get the dark dust separation too well, some of my flats messed up the data.

Yours looks good. If you incorporate Siril into your pre process you can carry out a background extraction which will even the background, and a green noise reduction, and a banding reduction which helps with DSLRs.

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I had a wee play with your image using PixInsight.

I managed to reduce the banding caused by not dithering and by the Canon DSLR, there's still some left in the centre. I also removed the magenta colour in the background and reduced the green in the boackground by 70%, as @Elp suggested. Lastly, a bit of noise reduction using the NoiseXTerminator script.

The stars I didn't touch, they are all good and have good colour. :thumbsup:

All in all, a good start and it'll make a big difference when you get PHD2 going.

1710300812_P5S1S2FB.png.8046fb3cca091d156dcc18997ab24000.thumb.png.89b0d75ff5d1eb0f30e835ac321e03c6.png

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Thats a fantastic image  if you are a newbie 🙂 , I don't think it is a particularly easy target for DSLR, especially to bring out the dark stuff which you are doing.

I have been trying this image recently but intermittant cloud has put a stop to it without obtaining much in good data. but will continue to try.
 

Do you have dark skies (when they are clear 🙂 ) as that really helps ?

Steve

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Thanks all for your helpful comments and encouragement. @Elp I havent heard of Siril before so this is something for me to have a look into, sounds like a useful tool. 

@Budgie1 This is fabulous, thank you so much for taking the time to do that it's made a big difference to the image 😁  I've heard of NoiseXTerminator but I don't have any experience of it - something for me to look into. I wondered what your process is for tackling the banding? 

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It looks very good!

It took me quite a while to get images to this standard when I started.

I don't notice it mentioned here, but what ISO are you running the camera at? Noise should in theory be less noticeable at higher iso, maybe 1600 or higher? I believe read noise gets lower as the iso increases.

Agree with others here that if you just manage to dither or drift a little things will improve a lot.

Have fun with your next target and congratulations!

 

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@teoria_del_big_bang thanks so much. I hope that you get some clear skies soon to try adding to your image. I have bottle 6 skies so it isn't ideal. I get issues with light pollution, sometimes it creates quite a gradient in my background which I find difficult to tackle. I think maybe the position of Iris is helping to avoid the gradient effect which I'm happy about 😁

@carastro thank you! I hope so too, looks like I might get the chance this week to have another bash 🤞

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3 minutes ago, Ikigai_sky said:

@teoria_del_big_bang thanks so much. I hope that you get some clear skies soon to try adding to your image. I have bottle 6 skies so it isn't ideal. I get issues with light pollution, sometimes it creates quite a gradient in my background which I find difficult to tackle. I think maybe the position of Iris is helping to avoid the gradient effect which I'm happy about 😁

Bortle 6 same as me, no idea looking at CO when I may get a chance again, probably near full moon , it usually is the case 🤣

Steve

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37 minutes ago, Ikigai_sky said:

I've heard of NoiseXTerminator but I don't have any experience of it - something for me to look into. I wondered what your process is for tackling the banding? 

With the PixInsight software there's a script called CanonBandingReduction, which is an automatic process, and that's what I used for your image. 

If you have PhotoShop then there's a good set of tools called Astronomy Tools, which includes a process called "Horizontal Banding Noise Reduction".

Affinity Photo may have something similar built-in, but I've never used it so I don't know if it has or not. ;)

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