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Old 28-09-2020, 07:16 AM
jahnpahwa (JP)
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Tarantula SHO

Finally! A break in the weather last night. Moon was out and about, nice viewing, but I couldn't pass up a night of imaging.


I set this up as I went to bed, it ran from 11pm to 5am, and I got 24 usable 240s subs on each Ha Oiii and Sii.


I really need to get going on some pixinsight techniques to keep some vibrancy in images after nuking green in SCNR.

I dont think I went too far with contrast here, though, so I'm happy with that. I think the data is actually pretty decent, astrobin link is

https://www.astrobin.com/4uwx3q/0/


If anyone wants to have a play with this data, to show me what can be done, let me know!


Processing is stack, mure denoise and combine, curves, local histogram in pixinsight, topaz denoise, then some colour balancing in gimp.
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Old 28-09-2020, 08:28 AM
RyanJones
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Nice work JP. Very natural looking ! The colours work really well and the framing gives it good context. Well done 👍
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  #3  
Old 28-09-2020, 11:31 AM
Placidus (Mike and Trish)
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Excellent.

Ways to improve:

(1) Zero point is way off. There's a lot of brown haze.
(2) Once you set the zero point, the colour balance is a bit too blue.
(3) There is room for a smidgin of wavelet sharpening.

Attached, I've had a very quick go at all three, but I really struggled to get the file size below the 200K limit. Your data are too good for 200K.

Fixing the zero point is dead easy: just very closely examine the RGB histogram, and set the zero point so that the "foothill" or "shoulder" of the histogram is at the origin in all three channels. Compare your histogram with mine and you'll see what I mean. The brown haze is not data, it's moon glow or sky glow or whatever.

Superb work!

Best,
Mike
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Old 28-09-2020, 11:56 AM
jahnpahwa (JP)
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Quote:
Originally Posted by Placidus View Post
Excellent.

Ways to improve:

(1) Zero point is way off. There's a lot of brown haze.
(2) Once you set the zero point, the colour balance is a bit too blue.
(3) There is room for a smidgin of wavelet sharpening.

Attached, I've had a very quick go at all three, but I really struggled to get the file size below the 200K limit. Your data are too good for 200K.

Fixing the zero point is dead easy: just very closely examine the RGB histogram, and set the zero point so that the "foothill" or "shoulder" of the histogram is at the origin in all three channels. Compare your histogram with mine and you'll see what I mean. The brown haze is not data, it's moon glow or sky glow or whatever.

Superb work!

Best,
Mike
Absolutely exactly what i was hoping for! Thanks heaps Mike, will get to it tonight!


And thanks too, Ryan, for the kind words!



I love this forum

Last edited by jahnpahwa; 28-09-2020 at 07:47 PM.
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  #5  
Old 29-09-2020, 05:09 PM
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xa-coupe (Jeff)
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A great effort. As well as my M16 I got about an hour of Tarantula .. but I can't get anything decent from it, certainly nothing like that!
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Old 29-09-2020, 06:16 PM
jahnpahwa (JP)
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Originally Posted by xa-coupe View Post
A great effort. As well as my M16 I got about an hour of Tarantula .. but I can't get anything decent from it, certainly nothing like that!

Thanks Jeff! I'm sure you'll be making these efforts look pedestrian in no time at all!

I bolted on another 3hrs of data last night and put the knife to the black point to get rid of brown haze as suggested by Mike. I think I've aligned channels too. Not sure about wavelet sharpening, maybe thats the next step for me.


I'm happy with the depth of that core area, and i think there is enough data in there now. As usual, ive been looking APODs of this target and now i look at mine and am left a bit cold

But overall, i think this is decent and might be the end of the SHO version for now.
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Old 29-09-2020, 06:45 PM
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xa-coupe (Jeff)
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I doubt I'll do better than that ... In fact, I'll play with the data I've got and post it ... but prepared to not be amazed .....
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Old 29-09-2020, 09:58 PM
jahnpahwa (JP)
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Jeff, I know you got it mate



Spreading my wings and throwing my images wherever they will fit on the internet. Put a super classic blue-purple electric version on cloudy nights for comparison. The SHO, even though proper, just doesn't do it for me on this target.



https://www.cloudynights.com/gallery...nebula-in-osh/
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