#1  
Old 11-09-2019, 11:13 AM
Xeteth (David)
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M42 Orion Nebula

Got my first nebula shot last night. Happy with how it came out considering it's really my first half-decent one and there was an 85% moon. The center looks rather blown out - I feel I'm going to need to start getting into filters to bring out the details in these nebula's.

52 x 1 Min subs
Darks/Flat/Bias frames


Equipment:
Explore Scientific ED102 FCD100 Triplet Apo
Canon 650D
Skywatcher ED50 Guidescope
ZWO ASI 290 MM-Mini Guidecam
EQ6-R Pro Mount

Software:
PHD2 Guiding
Astrophotography Tool for plate solving and capture

Stacked in DSS and a very basic processing pass was done in Photoshop (levels). I really need to learn how to do the whole processing thing... can anyone recommend any guides? Most I have found say 'do this' but not with the 'why', I want to understand what exactly I'm doing and why I'm doing it to enhance the data.

Taken in Melbourne, Bortle 8 skies.

Any and all tips/criticism welcome!
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  #2  
Old 11-09-2019, 12:42 PM
Jasp05 (Aaron)
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Looks like your off to a great start there David.

I recommend watching Astrobackyard on Youtube if you use photoshop. He has some really good tutorials on using PS. And the processes he uses are pretty basic and easy to remember for a beginner.

I'm still learning photoshop myself, but those videos helped immensely.

Orion is a tricky one to shoot with the core blowing out so easily. Try taking some 10-30sec subs and layer them in with your longer subs to retain the details in the core.
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Old 11-09-2019, 01:15 PM
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Great start. I can tell you some tricks but I can't offer a reason unfortunately.
Take some short exposures so you don't blow out the trap region.
Put the blown out version and the non blown out photos I photo shop layers and use the rubber tool to merge the two so you retain the trap and the nebulous putter regions.
Also run the dodge tool around the nebulosity and see if you can get a little more..it's there I bet.
Alex
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Old 11-09-2019, 02:57 PM
Sunfish (Ray)
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Looks good. Nice and crisp and colourful. Not sure why the core is blown out unless you have over stretched and then compensated with the black point. I have taken a few DSLR refractor Orion shots of one or two minute subs stacked in DSS and then edited in PS at 400iso without quite that much core. I tend to stack camera raw files in DSS and then save export adjustments with just a minimum 15% stretch to be able to see the result to 16bit tif. After that just a little little more stretch and black/ contrast and noise reduction in PS or levels with the right colour space.

Or stretch in another program like CCD prior to PS as PS will not always happily stretch a 16bit tif. If only DSS would output a camera Raw file.

Perhaps your flats or bias shots have gone wrong so you could try without them. Not sure you need bias on DSLR shots in DSS when you have dark substraction.
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Old 11-09-2019, 03:00 PM
Sunfish (Ray)
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Check Clark Vision website for more DSLR astro information than you could ever need.

https://clarkvision.com/articles/ast...ge.processing/
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Old 11-09-2019, 05:29 PM
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ChrisV (Chris)
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Very nice. Just repeating the others. M42 is difficult because of the large dynamic range - extremely bright core and much dinner surrounds. So maybe adding some short exposures to get the core. Then combining - the Photoshop users can tell you how to do that
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Old 11-09-2019, 06:00 PM
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rustigsmed (Russell)
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yes m42 is harder than average.
here is an easy tutorial which uses m42 as an example

cheers

EDIT actually putting the link in https://astrobackyard.com/deep-sky-image-processing/

Last edited by rustigsmed; 12-09-2019 at 05:12 PM.
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Old 11-09-2019, 07:21 PM
Ukastronomer (Jeremy)
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A1 +++
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Old 11-09-2019, 07:38 PM
RyanJones
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Hi David,

Great first effort. Well done

I am a DSLR user, a Photoshop processor and in Bortle 8 Melbourne skies.

The best way I have found to deal with high dynamic range targets is as simple as patience. Yes you can do short subs and combinations but balancing them isn’t quite as easy as it sounds to remain natural looking. I know your new to this and keen to get lots of images and trust me we all love that but spending time on one target pays big dividends. If you lower your ISO you may think you’ll loose out on the feint stuff. This isn’t true. The photons are still hitting your sensor, they just are very feint and get lost in the noise. This is where patience comes in. Take double, triple, quadruple the number of subs. What you’ll find is that you increase the signal to noise ratio substantially. You’ll get to a point where you won’t need to stretch the image as much to bring out the feint nebulosity. Less stretching means less chance of blowing out the core. There is no doubt in my experience that the better the data to start with and the less you have to play with it, the better the end result. There are ways to deal with the highlights individually in Photoshop and to isolate certain areas to enhance but you have to be careful with them and again I repeat, the less of this you have to do the better. These techniques can be used for fine tuning and adding depth.

You’re off to a cracking start so keep going and well done so far.

Cheers

Ryan
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Old 11-09-2019, 11:32 PM
Xeteth (David)
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Thanks to everyone for your comments and suggestions. It really is appreciated; the learning curve is bloody steep!

Quote:
Originally Posted by Jasp05 View Post
I recommend watching Astrobackyard on Youtube if you use photoshop.

Orion is a tricky one to shoot with the core blowing out so easily. Try taking some 10-30sec subs and layer them in with your longer subs to retain the details in the core.
I watch Trevor already, love his channel. Actually, he was partly the reason I also went with the Explore Scientific ED102. I'll look into some of his Photoshop tutorials for sure! Cheers.

Quote:
Originally Posted by xelasnave View Post
Great start. I can tell you some tricks but I can't offer a reason unfortunately.
Take some short exposures so you don't blow out the trap region.
Put the blown out version and the non blown out photos I photo shop layers and use the rubber tool to merge the two so you retain the trap and the nebulous putter regions.
Also run the dodge tool around the nebulosity and see if you can get a little more..it's there I bet.
Alex
That's a great tip - thanks. So far I've really just been playing around with levels but am learning quickly that you can easily blow things out and lose/waste a lot of your data if you go too far. Shorter exposures to capture the core then layering sounds like a really good way of capturing and keeping the right amount here! As for the dodge tool - I've never used it, I really am just starting out with Photoshop but I will definitely look into it (and more!). Thanks!

Quote:
Originally Posted by Sunfish View Post
Check Clark Vision website for more DSLR astro information than you could ever need.

https://clarkvision.com/articles/ast...ge.processing/
I've only had time to quickly go through this but it looks brilliant! I know what I'll be reading to/from work this week, thanks!

Quote:
Originally Posted by RyanJones View Post
If you lower your ISO you may think youíll loose out on the feint stuff. This isnít true. The photons are still hitting your sensor, they just are very feint and get lost in the noise. This is where patience comes in. Take double, triple, quadruple the number of subs. What youíll find is that you increase the signal to noise ratio substantially. Youíll get to a point where you wonít need to stretch the image as much to bring out the feint nebulosity. Less stretching means less chance of blowing out the core. There is no doubt in my experience that the better the data to start with and the less you have to play with it, the better the end result. There are ways to deal with the highlights individually in Photoshop and to isolate certain areas to enhance but you have to be careful with them and again I repeat, the less of this you have to do the better. These techniques can be used for fine tuning and adding depth.
That's some really good advice, thanks Ryan! Unfortunately Orion is only visible for about an hour between two dirty great apartment blocks near my backyard. But, I think it would be interesting if I did an hour or so each time I go out and after a good few runs I'd have enough data for a great image. A nice long-term project whilst I image other things as well. I'll give ISO 400 a go, thanks!
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Old 12-09-2019, 07:23 AM
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Nikolas (Nik)
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Quote:
Originally Posted by rustigsmed View Post
yes m42 is harder than average.
here is an easy tutorial which uses m42 as an example

cheers
um where?
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Old 12-09-2019, 05:12 PM
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rustigsmed (Russell)
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Quote:
Originally Posted by Nikolas View Post
um where?
whoops! updated now
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Old 12-09-2019, 06:44 PM
RyanJones
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If you struggle to get time to spend on Orion, another good target that has a tendency to blow out the core and has feint outer nebulosity is M17 or Swan Nebula. Itís bright enough to capture the main body with shorter sub lengths and you can probably spend a bit more time on it as it is further south than Orion. Might be another good one to practice with. Not nearly as good as Orion to look at though. You may struggle a little with the really outer nebulosity as it is feint Hydrogen Alpha and Iím not sure if you cameras stock filters will let through enough if itís not full spectrum modified but itís certainly worth a go.
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