I present to you my Fall project, the Andromeda Galaxy. The last time I imaged M31 was two years ago with my DSLR, but all other equipment being generally the same. I'm glad to finally give M31 a proper go with the astronomy camera, as it just explodes with color and little red nebulous regions within.

Equipment:

OTA: William Optics GT81 w/0.8x reducer/flattener (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

Accessories:

QHYCCD PoleMaster

Software:

SGP

PHD2

CdC

PixInsight

Acquisition:

Location: Atoka, OK and Ft. Griffin State Historic Park, TX for LRGB(Bortle 3), Flower Mound, TX for Ha(Bortle 7)

Dates: 11/2/18, 11/5/18, 12/1/18, 12/9/18, 12/15/18, 12/22/18, 12/23/18

Gain: 76 Offset: 15 for LRGB

Gain: 200 Offset: 50 for Ha

Camera temp: -20C

L: 143x300" ZWO

R: 46x300" ZWO

G: 44x300" ZWO

B: 40x300" ZWO

Ha: 115x300" Astrodon 5nm

Total integration time: 32hr 20min

64x darks per calibration (master from library)

30x flats per calibration

200x bias per calibration (master from library)

Preprocessing:

Batch PreProcessing script to generate calibrated images

StarAlignment

LocalNormalization

ImageIntegration

DrizzleIntegration

DynamicCrop each master

DBE each master

Luminance Processing:

Deconvolution

TGV & MMT noise reduction (via Jon Rista's method)

HistogramTransformation x2 (Linear > Non-Linear)

HDRMultiscaleTransform

LocalHistogramEqualization

MLT sharpening

MMT for slight star reduction

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

MMT to remove any artifacts left in the background

DBE to even out the background

Combined processed Red and Ha master with PixelMath:

Red*0.9 + Ha*0.1

Created HaRGB image with ChannelCombination

HaRGB Processing:

BackgroundNeutralization

ColorCalibration

SCNR Green

ArcsinhStretch x2

HistogramTransformation (Linear > Non-Linear)

HDRMultiscaleTransform

CurvesTransformation for saturation

ColorSaturation tool to specifically saturate the Ha regions

Combined HaRGB with Luminance using LRGBCombination

LHaRGB Processing:

MT for slight star reduction

UnsharpMask to harden up the soft stars slightly

SCNR Green

CurvesTransformation for final saturation tweak

Resampled to 40% for web posting