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Contains:  NGC 7023
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NGC 7023 - The Iris Nebula, 


            Josh Woodward
NGC 7023 - The Iris Nebula
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NGC 7023 - The Iris Nebula

Technical card

Dates:July 2, 2019July 4, 2019

ZWO L 1.25": 243x60" (gain: 76.00) -15C bin 1x1
ZWO RGB 1.25" Filters: 150x180" (gain: 76.00) -15C bin 1x1

Integration: 11.6 hours

Darks: ~60

Flats: ~12

Flat darks: ~25

Avg. Moon age: 15.55 days

Avg. Moon phase: 2.09%

Bortle Dark-Sky Scale: 5.00

Temperature: 22.00

Basic astrometry details job: 2788144

RA center: 21h 1' 30"

DEC center: +67° 55' 33"

Pixel scale: 1.582 arcsec/pixel

Orientation: 273.297 degrees

Field radius: 1.163 degrees

Resolution: 4296x3090

Locations: backyard, Chico, CA, United States

Data source: Backyard


I have tried my hand at this object with less than, let's say stellar results (bah duum bop;) This time I decided solve my glaring inadequacies by deluge of data. This was captured each night over the course of a week and a half. I had some obstacles to overcome. My first set of data was besieged by camera sag. I could not get that damn camera to fit snuggly within the compression ring. So out comes the pliers, problem solved. Next, I had trouble with getting automatic focusing to work with SGP. The sequences were abruptly ending mid sequence. I "solved"it by fiddling with the focus steps. It is the ugliest, zig zaggiest focus curve imaginable. But it worked. Finally, I struggled to get the SGP notifications to work. I ended up having to create a new gmail account to get that sucker going. Finally, after all the tweaking, fiddling and adjusting, wouldn't you know...high clouds. so this is the data set I ended up with.

Processing Process:

LRGB stacked in Pixinsight using BPP.

Star Alignment to Lum

Dynamic Crop to Lum saved process for RGB


R G B were Linear Fit to red.

Channel Combination RGB

Automatic Background Extraction of RGB

Photometric Color Calibration of RGB

Jon Rista's process of noise reduction using TGV Denoise and MultiScaleMedianTransform

Stretch using a small Histogram Transform to just bring out the brighter stars then a Masked Stretch at 160 background.


Automatic Background Extraction

Deconvolution using Kayron Mercieca process

Jon Rista's NR process again

Stretch using light Histogram Transform to jus bring out brighter stars and then Maksked Stretch at 110 background.

LRGBCombination with 50 lightness and 28 saturation

SCNR at 80%

Jon Rista ACDNR technique

HistogramTransform to clip some of the "black tail" to improve contrast

HDRMultiscaleTransform using combined star_mask+range_mask that protects the background

Morphological Transformation with 3 iterations and 40% using standard star_mask

Curves to boost contrast and saturation


light editing using the RAW filter.



Josh Woodward
License: None (All rights reserved)

Sky plot

Sky plot


NGC 7023 - The Iris Nebula, 


            Josh Woodward

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