Celestial hemisphere:  Northern  ·  Constellation: Cygnus (Cyg)  ·  Contains:  12 Cyg  ·  The star 9 Cyg  ·  The star φ Cyg
Getting plate-solving status, please wait...
Sh2-91 in HaRGBOHb, Brent Newton
Sh2-91 in HaRGBOHb, Brent Newton
Getting plate-solving status, please wait...
Sh2-91 in HaRGBOHb, Brent Newton
Sh2-91 in HaRGBOHb, Brent Newton

Equipment

Loading...

Acquisition details

Loading...

Description

I initially shot broadband RGB on this object from my Bortle 5 backyard but was unsure if I was properly reducing the LP gradient to preserve the subtle glow of the Milky Way on the right side. When OTSP came around the forecast indicated we would only have one clear night, so I took advantage of the Bortle 1 skies and retargeted this area, using PixInsight's Subframe Selector process and NSG script for Local Normalization, ensuring the Bortle 1 data had both highest weights and that it was used to Normalize the light-polluted data.

Preprocessing:
 - Darks, Flats, Flat Darks calibration
 - Cosmetic Correction
 - Subframe Selector
 - StarAlign, LocalNorm (NB), NSG (Broadband)
 - Image Integration

Starting Files:
 - R, G, B
 - Ha, Oiii 3nm
 - Hb 8.5nm


Housekeeping:
 - Channel Combine RGB
 - Crop
 - StarX, DBE, Star Screen blend
 - Image Solver


Narrowband Processing for Luminance:
 - BlurX
 - StarX
 - Clone Stamp for remaining star artifacts in the corners
 - PixelMath isolation and blending of Ha, Oiii, extracted RGB_L to form Master Luminance (Starless)
 - NoiseX, MMT using inverted masking

 - GHS for non-linear stretch
 - HT contrast tweaks
 - PixelMath to boost Oiii areas


RGB Processing:
 - SPCC
 - BlurX, StarX
 - (Stars given ArcSinH, HT stretch, SCNR, Curves for vibrance increase)
 - Pixel Math continuum isolation for application to RGB: Ha to R, Hb to B, Oiii to (G+B/2)
 - PixelMath blending of continuum-isolated NB data into RGB channels
 - Rista TGVD, MMT

 - HT stretch
 - SCNR G
 - ACDNR using Inv Mask
 - HT/Curves contrast and color tweaks

 - LRGB Combination
 - Further Curves tweaks for color, contrast
 - UnsharpMask
 - Star Screen
 - Bill's Star Reduction via PixelMath
 - Annotation

Comments

Revisions

  • Final
    Sh2-91 in HaRGBOHb, Brent Newton
    Original
  • Sh2-91 in HaRGBOHb, Brent Newton
    B
  • Sh2-91 in HaRGBOHb, Brent Newton
    C

B

Description: Starless

Uploaded: ...

C

Description: Annotated

Uploaded: ...

Sky plot

Sky plot

Histogram

Sh2-91 in HaRGBOHb, Brent Newton

In these collections

DSO
OTSP 2023