The Iris Nebula... and Mistake documented

Iris Nebula

I'm not afraid to admit mistakes and weaknesses when it comes to this hobby. I've learned a great deal but I also make assumptions that my calculations are correct. In this case, I wanted to get the dusty nebula trail going away from the Iris Nebula, but had the rotation off 90 degrees.

The Iris Nebula, also known as NGC 7023 and Caldwell 4, is a bright reflection nebula located in the constellation Cepheus. It is one of the most popular astrophotography targets in the northern sky. The nebula shines at a magnitude of +6.8 and is illuminated by a star designated HD 200775. The Iris Nebula lies approximately 1,300 light-years away from Earth and spans about six light-years across1 2 3. Its striking appearance resembles an ethereal flower blooming in the cosmic darkness 🌸✨.

Learn more

1 en.wikipedia.org | 2 constellation-guide.com | 3 skyandtelescope.org | 4 skyandtelescope.org

Photo Capture Info:

(141) 3 Minute exposures - 7 hrs, ~3 mins
(2 frames discarded by WBPP, ~30 manually discarded)

Optical Equipment Used:

Optolong L-Pro Light Pollution Filter
Scope: William Optics Zenithstar 61II APO Refractor
Camera: ZWO 183MC Pro
Guide scope: William Optics 32mm Guide scope
Guide camera: ZWO ASI120mm-mini

Computerized Equipment and Software:

Mount: iOptron GEM 28
Beelink Mini PC S Intel 11th Gen
Focuser: ZWO EAF (Electronically Assisted Focuser)
Filter Wheel: ZWO 5 Position
Pegasus Pocket Powerbox
NINA 3.1 used for capture
PixInsight for Processing

PixInsight Processing

Calibration

Weighted Batch Preprocessing

Master Dark, Master Flat, Output Pedestal @ %0.01

Light Frame Data

One Shot Color from 294MC Pro

WBPP Pipeline Data

PixInsight Processing Details

Analyzed frames using Subframe Selector and thew away about 30 frames due to clouds and a few tracking errors.
WBPP used for calibrating and stacking using (R,G,B in separate channels and recombined drizzle @ 1x)
GradientCorrection used to remove most of the gradient
Graxpert Script to remove remaining gradient
BlurXterminator Correct Only to fix any star issues
Used SpectrophotometricCC in RGB mode to color correct everything
Histogram Stretch to get to Linear State
Removed Stars using StarXTerminator
NoiseXterminator @ 90
GeneralizedHyberbolicStretch in Linear mode to bring histogram closer to the black point
HDRMultiscaleTransform to highlight the Iris
Slight S-Curves Adjustment
LocalHistogramEqualization @ 25
LocalHistogramEqualization @ 75
Created Luminance Mask for use in bring out Blue in the Iris.
Curves on the blue channel to bring out the slightly more blue in the outer arms
NoiseXterminator @ 65
Added back stars using PixelMath
Used Curves to add Saturation to stars and nebula.
ICCProfileTransformation (Ready image for the Web)
Rotated image 90 degrees Counter Clockwise to properly orient the Iris and make fun of my framing :-)

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