Saturday, August 31, 2019

Cocoon Nebula (2019) - HaRGB with RGB Stars

Addendum:
Processing Flow on the Bottom

Surprisingly this is my first image of the this colorful emission/reflection nebula.  There are certain objects that most astrophotographers do when they are first starting out like the Orion Nebula.  The Coccon is not that popular but it is one that people in the Northern Hemisphere usually do with in the first year or so.  For a number reasons I am just getting around to it now.  I was planning on doing a normal LRGB image but then I saw a fabulous image on Astrobin by Luca Marinelli (https://www.astrobin.com/415781/E/?nc=all) where he added a whole bunch of Ha data.  I decided to give it shot as well.  Although I did not capture as much Ha, I did capture enough to see the streamers (jets) that come off the top and bottom of the nebula (it is very faint even with seven hours worth of Ha).

The Cocoon Nebula (IC 5146) is about 15 light-years wide and 3,300 light years away towards constellation of the Swan (Cygnus).  The nebula itself is a young star-forming region glowing inside a dim molecular cloud which extends to the left on the image.  Massive amounts of excited hydrogen gas account for the reddish glow of this stellar nursery along with many hot young blue stars.  The source of the glow is the bright star near the center of the nebula estimated to only a few hundred thousand years old.   

I find processing HaRGB images to be the toughest of all, even harder than SHO or HOO for some reason and this was no exception.  I was trying to keep a natural look yet show the Ha jets on the top and bottom, however, it seems one sacrifices for the other.  Using PixInsight I did a RGB combination, then a LRGB combination, and then combined the Ha into the red channel for the final combination.  I tried a last combination of adding the Ha as a luninosity layer but it took away from the natural look that I was after.  I also have to give a shout out to Gary Imm for assisting me with combining RGB stars into a narrowband image.  


IC 5146 - Cocoon Nebula
Home Monroe, CT
Date: 8-1-19, 8-4-19, 8-10-19, 8-11-19, 8-19-19, 8-20-19, 8-23-19
Camera: ZWO ASI1600MM-Pro
Telescope: Astro-Tech AT115EDT 115mm Refractor Telescope
Barlow: None
Focal Length: 805mm
f/7
Focal Reducer: Astro-Tech 0.8x Focal Reducer/Field Flattener for Refractor Telescopes
Mount: Orion Atlas Pro
Filter Wheel: ZWO EFW 8x 1.25"
Filter: ZWO Ha, L, R, G, B
Focuser: ZWO EAF
Autoguiding: QHY-5L-II-M attached to an Agena 50mm Guide Scope with Helical Focuser
Exposure: Ha 140 x 180s, L 169 x 60s, R 80 x 60s, G 67 x 60s, 78 x 60s
Gain: 139
Offset 21
Temp: 17 C
Post Processing: PixInsight, Photoshop
https://kurtzeppetello.smugmug.com/
http://astroquest1.blogspot.com/


Processing Flowchart
PixInsight Processing Flow Diagram 
ALL Master Images - After Stacking
1
STF
2
Dynamic Crop
3
Rename
RGB
4
RGB Combination
5
Dynamic Background Extraction (DBE) 
6
Histogram Transformation
7
CIE-L extract Mask 
8
TGV
9
Curves/Histogram Transformation - Darken Background
Luminosity
10
Automatic Background Extraction (ABE)
11
Histogram Transformation
12
Starmask
13
Morphological Transformation
LRGB
14
Split RGB
15
LRGB Combination
16
CIE-L extract Mask
17
TGV
Ha
18
ABE
19
Histogram Transformation
20
Range Mask
21
TGV 2x
HaRGB
22
Split LRGB
23
Open RGB
24 
Starmask RGB
25
PixelMath LRGB Channels with Ha in place of Red
26
Apply to RGB
Done in PixInsight

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