LDN1147 - Dark Nebula of Cepheus

This complex of dust is located some 1300 light-years away in the constellation Cepheus, not too far from the popular Iris Nebula. Since this nebula is not light-emitting (hence the "dark" nebula), very dark skies away from light pollution are needed to display the contrast between the faintest of dust and the background sky. For that reason, I took advantage of some of the darkest skies in the nation to capture this image.

Some interesting bits in this image include the galaxy NGC6951 near the left edge of the image. In comparison to the foreground stars and dust, which is cosmically speaking rather near, NGC6951 lies 75 million light-years from Earth.

Another exciting thing to note is that stars are forming within these dark cloud cores. Most notable is HH215 in the upper-right of the image. If you look closely at the "peak" of the nebula, you can see the bright gas ejection caused by the newborn star.

Equipment:
OTA: William Optics GT81 w/0.8x reducer/flattener (382mm fl at f/4.7)
74mm aperture stop-down ring (helps optical flaw by bringing 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

Accessories:
QHYCCD PoleMaster
DeepSkyDad Autofocuser AF1

Software:  
SGP
PHD2
PixInsight

Acquisition:  
Location: Marathon Motel & RV Park, TX (Bortle 1)
Dates: 7/14/2023, 7/15/2023, 7/16/2023, 7/17/2023, 7/18/2023
Gain: 76 Offset: 15
Camera temp: -10C
L: 203x180" ZWO 1.25in
R: 103x180" ZWO 1.25in
G: 101x180" ZWO 1.25in
B: 94x180" ZWO 1.25in
Total integration time: 25hr 3min
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
ImageIntegration
DrizzleIntegration
DynamicCrop each master
DBE each master

Luminance Processing:
BlurXTerminator
NoiseXTerminator
HistogramTransformation
Created a starless copy using StarXTerminator and pushed nebulosity with PixelMath function "1-(1-$T)*(1-$T)"
Blended starless with L using PixelMath function "F=0.6; (1-(1-$T)*(1-s)*F)+($T*~F)". (s=starless photo)
LocalHistogramEqualization

Created RGB image with ChannelCombination

RGB Processing:
SpectrophotometricColorCalibration
SCNR Green
BlurXTerminator
NoiseXTerminator
ArcsinhStretch x3
HistogramTransformation
CurvesTransformation for background balance
Created a starless copy using StarXTerminator and pushed nebulosity with PixelMath function "1-(1-$T)*(1-$T)"
Blended starless with L using PixelMath function "F=0.6; (1-(1-$T)*(1-RGB_s)*F)+($T*~F)". (RGB_s=starless photo)
HistogramTransformation for color balance

Combined RGB with Luminance using LRGBCombination

LRGB Processing:
SCNR Green
CurvesTransformations for contrast, saturation, and color balance
Invert>SCNR Green>Invert with a mask to remove magentas
MorphologicalTransformation to slightly reduce star sizes
Further pushed nebulosity using a nebula-only mask and HistogramTransformation
Selectively processed the galaxy with LHE, HT, Curves, and MLT
NoiseXTerminator
IntegerResample to downsample 3x