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Contains:  Triangulum galaxy, M 33, NGC 598
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The Triangulum Galaxy - M33, 


            Andrew Klinger
The Triangulum Galaxy - M33

The Triangulum Galaxy - M33

Technical card

Resolution: 4084x3136

Dates:Nov. 17, 2019

ZWO B 1.25": 16x300" (gain: 76.00) -20C bin 1x1
ZWO G 1.25": 16x300" (gain: 76.00) -20C bin 1x1
Ha 5nm: 85x600" (gain: 200.00) -20C bin 1x1
ZWO L 1.25": 76x300" (gain: 76.00) -20C bin 1x1
ZWO R 1.25": 16x300" (gain: 76.00) -20C bin 1x1

Integration: 24.5 hours

Darks: ~64

Flats: ~30

Bias: ~200

Avg. Moon age: 19.65 days

Avg. Moon phase: 75.33%

Bortle Dark-Sky Scale: 3.80 job: 3159896

RA center: 1h 33' 51"

DEC center: +30° 39' 36"

Pixel scale: 2.025 arcsec/pixel

Orientation: 273.977 degrees

Field radius: 1.448

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

Data source: Traveller


M33 lies in the constellation Triangulum and is the third largest galaxy in our Local Group (the others being ourselves and Andromeda). Sprinkled throughout the galaxy's arms you can see red blotches, which are nebula made of mostly ionized hydrogen. Most notably is NGC604 in the upper right position in galaxy. NGC604 is 100 times the size of the Orion Nebula (M42), and with M33 being 3 million light years away, you can think of just how huge that thing is for us to see details in it!

OTA: William Optics GT81 w/0.8x reducer/flattener (382mm fl at f/4.7)
74mm aperture stop-down ring (brings scope to f/5.2)
Mount: Orion Sirius EQ-G (HEQ-5)
Guidescope: Orion 50mm guidescope
Guiding camera: Orion StarShoot Autoguider
Imaging camera: ZWO ASI1600MM-Cool

DeepSkyDad Autofocuser AF1
QHYCCD PoleMaster


Location: Atoka, OK for LRGB(Bortle 3), Flower Mound, TX for Ha(Bortle 7)
Dates: 11/17/19, 11/18/19, 11/23/19, 12/30/19
Gain: 76 Offset: 15 for LRGB
Gain: 200 Offset: 50 for Ha
Camera temp: -20C
L: 76x300" ZWO 1.25in
R: 16x300" ZWO 1.25in
G: 16x300" ZWO 1.25in
B: 16x300" ZWO 1.25in
Ha: 85x600" Astrodon 5nm 1.25in
Total integration time: 24hr 30min
64x darks per calibration (master from library)
30x flats per calibration
200x bias per calibration (master from library)

Batch PreProcessing script to generate calibrated images
DynamicCrop each master
DBE each master

Luminance Processing:
Blended Ha regions into the Luminance by using PixelMath equation: "L+(max((1.5*Ha),L))"
TGV & MMT noise reduction (via Jon Rista's method)
ArcsinhStretch x2
MLT sharpening

Preparing separate R,G,B masters for combination (applied to each master individually):
TGV & MMT noise reduction (via Jon Rista's method)
LinearFit to B master

Preparing Ha master for combination:
TGV & MMT noise reduction (via Jon Rista's method)
Removed stars with several iterations of MMT and MT

Combined processed Red and Ha master with PixelMath equation: "Red*0.8 + Ha*0.2"

Created HaRGB image with ChannelCombination

HaRGB Processing:
TGV & MMT noise reduction (needed another round because of low RGB integration time)
SCNR Green
ArcsinhStretch x2
CurvesTransformation for contrast and background balance
CurvesTransformation for saturation

Combined HaRGB with Luminance using LRGBCombination

LHaRGB Processing:
CurvesTransformation contrast and color adjustments
MT for slight star reduction
UnsharpMask to harden up the soft stars slightly
SCNR Green



Andrew Klinger
License: None (All rights reserved)

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The Triangulum Galaxy - M33, 


            Andrew Klinger