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  #1  
Old 11-03-2018, 11:12 AM
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poppasmurf (Shane)
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Ngc 1365

Not sure if this is good enough to put here or should still be in beginner section, but hey have at it people.
Object: NGC 1365

Shane

Object Info:
NGC 1365, also known as the Great Barred Spiral Galaxy, is a barred spiral galaxy about 56 million light-years away in the constellation Fornax. The core is an oval shape with an apparent size of about 50? × 40?. The spiral arms extend in a wide curve north and south from the ends of the east-west bar and form an almost ring like Z-shaped halo. The central mass in an active galactic nucleus rotates close to relativistic limit (the dimensionless spin parameter is larger than 0.84).

Number of Subs:
L 63 , R 30 , G 30 , B 30
Sub Length:
300sec
Total Integration Time:
12.75 hrs
Date Captured:
20/12/2017 - 10/03/2018
Imaging Camera:
Moravian G2 2000
Imaging Telescope:
GSO RC8 CF
Reducer: yes
Focal Length:
1625; 1233 reduced
Image Scale:
0.94 arcsec/pixel; 1.24 arcsec/pixel reduced
Field of View:
19 x 25 arcmin; 25 x 33 arcmin reduced
Mount:
SW NEQ6 Pro, Rowan belt modded
Guide Scope:
Orion ST80
Guide Camera:
Prostar LP colour (toupcam)
Capture Software:
APT Astrophotography Tool
Guide Software:
PHD Guiding 2
Processing Software:
PixInsight
Attached Thumbnails
Click for full-size image (LRGB NGC 1365dc.jpg)
151.1 KB157 views
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  #2  
Old 11-03-2018, 11:48 AM
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Ryderscope (Rodney)
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Good one Shane. Nice colour and details in the galaxy. The only comment that I would make is to look at noise management in the background of the image. A good NGC1365 and well worthy of presentation.
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  #3  
Old 11-03-2018, 12:17 PM
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Likewise, I think the galaxy looks really good - you must be happy with that! Love the star colours too.

Within PI, suggest using MLT to reduce background noise:
Somewhere between 4 and 7 levels, with a Linear Mask to protect the galaxy. Need to play with the settings.

Then darken the resulting background a tad .... maybe using a Range Selection mask with HT to adjust the black points.

Lovely target ... have not yet tried this one.
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  #4  
Old 11-03-2018, 07:21 PM
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poppasmurf (Shane)
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Thanks for the feedback guys. I will have a go at a reprocess when I get a chance and try knocking the noise on the head. I am still learning and playing with settings in PI.

Shane
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  #5  
Old 12-03-2018, 08:53 AM
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Looks good, Shane. A little clean up and it will be even better!
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  #6  
Old 12-03-2018, 06:02 PM
Placidus (Mike and Trish)
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Well done! A goodly exposure. Colours look good, as is the detail in the core. My only suggestion would be to push it a little less hard, so as to emphasize the galaxy more and the background less. Stars might end up smaller too.



Very best,
Mike
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  #7  
Old 13-03-2018, 08:59 AM
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Thanks Rick and Mike. Still haven't had a chance to repro yet. Maybe later today after babysitting my grandson and before work.

Shane
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  #8  
Old 13-03-2018, 12:45 PM
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Did a bit of a repro, improved noise(I think) but lost a bit of colour. This processing game is a real challenge.

Shane
Attached Thumbnails
Click for full-size image (LRGB NGC 1365 repro.jpg)
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  #9  
Old 13-03-2018, 07:24 PM
Placidus (Mike and Trish)
Narrowing the band

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To us, the first version was hugely better. It showed lots of fine detail in the inner core of the galaxy. We'd suggest that instead of trying to smooth out the noise, you use a less curvy stretch, i.e. use a somewhat more linear stretch, not trying to bring out super-faint distant background galaxies, so the sky ends up much, much darker, but the gorgeous detail and colour that you have in the galaxy remains.

The only really good way to get super-faint distant galaxies against a grit-free sky is to do many nights worth of exposure.

Don't be discouraged: what you have is really, really good.

Best,
Mike
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  #10  
Old 13-03-2018, 09:12 PM
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Quote:
Originally Posted by Placidus View Post
To us, the first version was hugely better. It showed lots of fine detail in the inner core of the galaxy. We'd suggest that instead of trying to smooth out the noise, you use a less curvy stretch, i.e. use a somewhat more linear stretch, not trying to bring out super-faint distant background galaxies, so the sky ends up much, much darker, but the gorgeous detail and colour that you have in the galaxy remains.

The only really good way to get super-faint distant galaxies against a grit-free sky is to do many nights worth of exposure.

Don't be discouraged: what you have is really, really good.

Best,
Mike
Thank you for more helpful criticism, I tend to agree and much preferred the first version noise and all. When time permits I will do another repro using your suggestion of a "less curvy stretch".

Again thank you for very constructive criticism . Also don't worry I don't discourage that easily , if I did I doubt I would have got into AP at all.

Shane
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  #11  
Old 14-03-2018, 08:08 AM
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RickS (Rick)
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Some gentle noise reduction that targets the faint areas would help too, Shane, but you need a light touch.
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  #12  
Old 14-03-2018, 08:27 AM
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poppasmurf (Shane)
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Cheers for the suggestion Rick, much appreciated.

Shane
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  #13  
Old 14-03-2018, 12:04 PM
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poppasmurf (Shane)
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Hopefully I did the advice you kind people have given justice.
Here is another repro for perusal and critcism.

Shane
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