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Contains:  NGC 2359, IC 468
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Thor's Helmet (NGC 2359) imaged in SHO, 





    
        

            Andrew Klinger
Thor's Helmet (NGC 2359) imaged in SHO

Thor's Helmet (NGC 2359) imaged in SHO

Technical card

Resolution: 2371x1985

Dates:March 7, 2018

Frames:
Astrodon Ha 5nm: 93x300" (gain: 200.00) -20C bin 1x1
Astrodon OIII 3nm: 16x300" (gain: 200.00) -20C bin 1x1
Astrodon SII 3nm: 20x300" (gain: 200.00) -20C bin 1x1

Integration: 10.8 hours

Darks: ~64

Flats: ~32

Bias: ~200

Avg. Moon age: 20.33 days

Avg. Moon phase: 68.83%

Bortle Dark-Sky Scale: 4.33

Astrometry.net job: 2053012

RA center: 109.496 degrees

DEC center: -13.084 degrees

Pixel scale: 1.688 arcsec/pixel

Orientation: 89.982 degrees

Field radius: 0.725 degrees

Locations: Atoka dark site, Atoka, Oklahoma, United States; Backyard, Flower Mound, Texas, United States

Data source: Unknown

Description

Equipment:
OTA: William Optics GT81 w/0.8x reducer (382mm fl at f/4.7)
Mount: Orion Sirius EQ-G (HEQ-5)
Guidescope: Orion 50mm guidescope
Guiding camera: Orion StarShoot Autoguider
Imaging camera: ZWO ASI1600MM-Cool

Software:
SGP
PHD2
CdC
PixInsight

Acquisition:
Location: Flower Mound, TX for Ha (Bortle 7), Atoka, OK for Oiii (Bortle 3), and Caddo National Grassland, TX for Sii (Bortle 3)
Dates: 2/7/18, 2/17/18, 3/2/18, 3/7/18
Gain: 200 Offset: 50
Camera temp: -20C
SII: 20x300" Astrodon 3nm 1.25"
Ha: 93x300" Astrodon 5nm 1.25"
OIII: 16x300" Astrodon 3nm 1.25"
Total integration time: 10hr 45min
64x darks per calibration (master from library)
32x flats per calibration
200x bias per calibration (master from library)

Preprocessing:
Batch PreProcessing script to generate calibrated images
StarAlignment
ImageIntegration
DrizzleIntegration
DynamicCrop (BIG crop!)
DBE
LinearFit to Ha

Duplicated all three masters. One set used for tonemap creation, and one set used for a synthetic Lum.

Preparing masters for the tonemap (all processes applied to each master individually):
TGV and MMT noise reduction (via Jon Rista's method)
Histogram Transformation x2 (linear -> non-linear)
Created a starmask and removed stars via MMT and MorphologicalTransformation

Tonemap processing:
SHO masters assigned to RGB channels respectively to create a color image
2 different curves adjustments (a and b channels) using ColorMask Script to target individual colors and adjust them to an aesthetically pleasing composition
Invert -> SCNR green -> Invert -> SCNR green to remove magenta and green colors
HistogramTransformation
CurvesTransformation

L Processing:
Created a synthetic luminance with PixelMath using the following formula: Ha*0.2 + Oiii*0.7 + Sii*0.1
Deconvolution
HistogramTransformation x2 (linear -> non-linear)
LHE

Combined the Luminance with the Tonemap using LRGBCombination

Post-combination adjustments:
HistogramTransformation
SCNR green
CurvesTransformation
MMT for slight noise reduction
HistogramTransformation to move black point in
MorphologicalTransformation for slight star size reduction
Resampled to 60% for web posting

Comments

Author

ak_astro
Andrew Klinger
License: None (All rights reserved)
2411
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Thor's Helmet (NGC 2359) imaged in SHO, 





    
        

            Andrew Klinger