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Contains:  NGC 7023, NGC7023, VdB139
Getting plate-solving status, please wait...
Iris Nebula - OSC, 


            Jonathan W MacCollum
Powered byPixInsight

Iris Nebula - OSC

Technical card

Imaging telescopes or lenses:Orion 203/1000 f/4.9

Imaging cameras:ZWO ASI071MC Pro

Mounts:Celestron CGEM

Guiding telescopes or lenses:ZWO OAG

Guiding cameras:ZWO ASI 178MM

Software:PixInsight PinInsight 1.8.5Isbeorn N.I.N.A.PHD 2

Filters:Hutech IDAS LPS D1 2"

Accessory:Skywatcher 2" Coma Corrector f/4

Dates:July 24, 2019

Frames: 97x120"

Integration: 3.2 hours

Avg. Moon age: 21.63 days

Avg. Moon phase: 55.45% job: 2840155

RA center: 21h 0' 18"

DEC center: +68° 4' 28"

Pixel scale: 0.983 arcsec/pixel

Orientation: -3.075 degrees

Field radius: 0.810 degrees

Resolution: 4928x3276

Data source: Backyard


**NGC 7023 - Iris Nebula**


* Orion 8in f4.9 1000mm Flocked / replaced GSO primary mirror

* Guiding with ZWO OAG and asi178mm camera

* ASI071mc one-shot-color cam

* Hutech IDAS LPS D1 Filter

* Celestron CGEM Mount


* Lights:
97x120.0s at -10C on 2019-07-24

* Flats: combination of sky flats and ceiling flats for each session

* Darks: 60x120s at -10C

* Bias: None

* Bortle Dark-Sky Scale: 4.00

* Pixel scale: 0.981 arcsec/pixel

* Orientation: 0 degrees

**Pre-Processing with PixInsight:**

* Calibrated and stacked using [LVA PreProcessing Steps](

* Integrated best 97 of 121 frames selected using a combination of Blink Subframe Selector

Processing Steps:
I've decided my processing workflow may be best summarized with pseudocode:


/// Pre Processing
let rgb =

Image Integration

|> Dynamic Crop

|> Dynamic Background Extraction

|> Background Neutralization <| (4 Previews |> Preview Aggregator)

|> Color Calibration

|> Image Solver

|> Photometric Color Calibration

|> RGB Working Space <| (1,1,1)

/// Synthetic Luminance

let l_orig =


|> extract synthetic luminance

/// Background Noise Reduction

let l_nr =


|> Tgvnr // Small Scale Noise Reduction

|> Mmtnr // Large Scale Noise Reduction

/// High-Signal Sharpening

let l_sharpen =


|> Deconvolution // 5-layer regularization no deringinging

|> Replace stars <| star mask <| l_orig

|> Mmt sharpen

/// Prepare mask for combining Low-Signal background with High Signal Foreground

let l_combine_mask =


|> stf

|> hist stretch cliping whites and blacks

|> blur

/// Combine Low-Signal background with High Signal Foreground

let l =

l_sharpen*l_combine_mask + l_nr *~l_combine_mask

|> curves for contrast enhancement

/// RGB cleanup and combination

let final =


|> scnr green

|> Tgvnr // Small Scale Noise Reduction

|> Mmtnr // Large Scale Noise Reduction

|> Additional round of DBE and SCNR

|> HSV Repair Separation Script

|> Arcsinh Stretch

|> lrgb combination(l)

|> histogram transfromation

|> cleanup artifacts from hotpixels with clonestamp


* Save as JPEG



Jonathan W MacCollum
License: Attribution-NoDerivs Creative Commons

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Iris Nebula - OSC, 


            Jonathan W MacCollum