Celestial hemisphere:  Northern  ·  Constellation: Gemini (Gem)  ·  Contains:  13 Gem)  ·  7 Gem)  ·  Calx (μ Gem  ·  Gem A  ·  IC 443  ·  IC 444  ·  Part of the constellation Gemini (Gem)  ·  Praepes (η Gem  ·  Tejat Posterior  ·  Tejat Prior  ·  The star 12 Gem  ·  The star 6 Gem  ·  The star 9 Gem  ·  The star Propus  ·  The star Tejat
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The Jellyfish Nebula (IC 443) RGB + SHO, Brent Newton
The Jellyfish Nebula (IC 443) RGB + SHO
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The Jellyfish Nebula (IC 443) RGB + SHO

Getting plate-solving status, please wait...
The Jellyfish Nebula (IC 443) RGB + SHO, Brent Newton
The Jellyfish Nebula (IC 443) RGB + SHO
Powered byPixInsight

The Jellyfish Nebula (IC 443) RGB + SHO

Equipment

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Acquisition details

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Description

The first image that came out of my WO Star71-II was actually during the Lunar Eclipse, but I will still count IC 443 as First Light because this project really put the scope through its paces. After years on doublets and SCTs I am thoroughly impressed by the flat field and the round-ness of star all the way to the edge of the field.

I used this lengthy project to sort-of "follow along" the Inside PixInsight book. Many thanks to Warren Keller for this resource, it really halped me maintain a sense of direction, especially when I could only find decent lengths of time to work on this during my weekends.

IC 443 is a dual Supernova remnant north of Orion's head. Originally thought to be a single event, the shape of the blast waves eventually caused the realization that two supernovae happened in this region. The main older one happened ~100,000 years ago with the newer one being only ~8,000 years old. I would also like to note the small planetary nebula sitting in the larger emission nebula of IC 444; this nebula is called HoCr-1 and was only discovered in 2006. So far I can find very little information on this nebula

Pixinsight Calibration & Stacking:
- Calibration using Darks, Flats
- Subframe Selector for weights, Star Align, Local Normalization, 3x Drizzle

Prelim Processing:
- All channels aligned to Ha master
- Crop for all channels
- Several DBE passes

Narrowband Processing:
- Deconvolution per channel using Dynamic PSF, Starmask
- Noise Reduction using TGV + MLT (modified from Rista method)
- Copy of Ha stretched using ArcSinH + HT (for use as Luminance)
- Dark Structure Enhancement & Star Reduction on Ha Luminance

"Tone Mapping" Processing
- Channels stretched using STF / HT
- Starnet for star removal (plus creation of star masks)
- Another pass of MLT for heavy NR, further HT stretch

RGB Processing:
- Linear Fit to G
- Luminance Extracted
- NR using TGV, MLT for Chrominance, Luminance separately
- Standard STF / HT stretch

Combined RGB / SHO Processing:
- SHOAIP Script to mix RGB and Narrowband using starless Tone maps
- Added Ha to R (~100%)
- Added Oiii to G (~40%)
- Added Oiii (~40%)and Sii (~20%) to B
- Several Curves tweaks using various Luminance and starless masks for color tweaks (in Lab a*b modes) and saturation increase
- Another pass of Star Reduction
- Exported to Photoshop for final edits
- Annotated image copy

Photoshop:
- a few more color tweaks, including removing some blue background color cast caused by Oiii
- Partially replaced the 2 bright stars with the RGB image since the NB-heavy mix had turned slightly green
- Added signature, downsized image

Comments

Revisions

  • The Jellyfish Nebula (IC 443) RGB + SHO, Brent Newton
    Original
  • The Jellyfish Nebula (IC 443) RGB + SHO, Brent Newton
    E
  • The Jellyfish Nebula (IC 443) RGB + SHO, Brent Newton
    F
  • The Jellyfish Nebula (IC 443) RGB + SHO, Brent Newton
    H
  • The Jellyfish Nebula (IC 443) RGB + SHO, Brent Newton
    I
  • Final
    The Jellyfish Nebula (IC 443) RGB + SHO, Brent Newton
    K

E

Description: "True Color" Broadband + Narrowband mix

Sii applied to R
Hα applied to R, B in a ~1 : 3 ratio to simulate Hß and Γ emission lines
Oiii applied to G and B in ~1 : 0.57 ratio

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F

Description: Annotation

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H

Description: Master Luminance of blended Hα, Oiii, Sii

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I

Description: Original 2019 Edit

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K

Description: 2023 Gallery Print

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The Jellyfish Nebula (IC 443) RGB + SHO, Brent Newton

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Central USA

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ASI1600MM-P 350mm FL
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