IC443 aka The Jellyfish Nebula in Gemini

IC443 Jellyfish


Here is the pure RGB used to recover star colours:

Jellyfish in RGB

[from Wikipedia:

IC 443 (bright "jellyfish" shaped nebula near the top) is a Super Nova Remnant (SNR) and has an angular diameter of almost 2 full moons. At the estimated distance of 5,000 ly from Earth, it corresponds to a physical size of roughly 70 light years.

The remnant's age is still uncertain. There is some agreement that the supernova happened between 3,000 and 30,000 years ago. Near the apex of the nebula is a neutron star, relic of a SN explosion. The location in a star forming region and the presence of a neutron star favor a Type II supernova, the ultimate fate of a massive star, as the progenitor explosion.

The remnant is evolving in a rich and complex environment, which strongly affects its morphology. Multi-wavelength observations show the presence of sharp density gradients and different cloud geometries in the surroundings of IC 443. Massive stars are known to be short lived (roughly 30 million years), ending their life when they are still embedded within the progenitor cloud. The more massive stars (O-type) probably clear the circum-stellar environment by powerful stellar winds or photoionizing radiation. Early B-type stars, with a typical mass between 8 and 12 solar masses, are not capable of this, and they likely interact with the primordial molecular cloud when they explode. Thus, it is not surprising that the SNR IC 443, which is thought to be the aftermath of a stellar explosion, evolved in such a complex environment. For instance, an appreciable fraction of supernova remnants lies close to dense molecular clouds and most of them show clear signs of interaction with the adjacent cloud.

Sh2-249 is the fainter cloud of gas and IC443 is interacting with it as IC443 expands.

Camera: Moravian G4 (16803) w Astrodon Gen II filters
Scope: AP155EDF w Feathertouch Focuser and Starlight Instruments Focus Boss II
RGB 10/10/10 x 10 minutes
SII / H-Alpha / OIII  15 / 11 / 17 x 20 min
Paramount MX guided w ST-402 and Borg 60mm achromat
TSX and CCD-Commander

All calibration and initial processing through to the RGB and separate NB frames in PixInsight
Subsequent assembly of final image in Photoshop CC

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Captured Feb / March 2022
Lucknow, Ontario

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