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