IC 443 Jellyfish SNR (Gemini) in SHO
Oct/Nov 2023; Askar 151phq;  AP Mach2 GTO ; ASI6200MM, - Baader RGB & 6.5nm NB CMOS opt. filters
H,O,S: (35,30,31 x 450s, Bin 1, Gain 200)
R,G,B: (12,8,8 x 180s Bin 1, Gain 100) (for stars)
Total integration time = 13.4 hrs

The Jellyfish Nebula (IC 443 or Sh2-248) is a supernova remnant (SNR) that originated within, and now interacts with, an existing molecular cloud.   Like other SNRs, the outward expansion of the supernova is seen as spheroid shells have a characteristic fractal, bubbly appearance created by tendrils of material that looks more like a net than a shell or surfaces.  However, there seems to be a lot more material in this SNR than many others.  This abundance of material appears to have been provided by the molecular cloud dust.  The shells or nets are a mixture of material originating both from the supernova and the cloud.
The spheroid shape of the supernova explosion is also shaped by the variations in the density and apparent viscosity of molecular cloud it is expanding into.  Further complicating the shape of IC 443 is that this SNR is believed to have result from at least two separate supernovae occurring between 3,000 and 30,000 years ago, causing multiple lobes.  
Unlike some other SNRs, the light emissions from the SNR and cloud are energized by thermal radiation from young stars originating from the molecular cloud, and not a central pulsar/neutron star.  The various colours are created by a combination of the density and composition of the material and the amount and energy of the UV light energizing the material.   
The object is roughly 5000 ly away, and 70 ly across, and is roughly 3,000 to 30,000 yrs old.

I feel fortunate to have capture this object in the middle of rainy season, but it was definitely a struggle.   I ended up throwing away more frames due to atmospheric moisture (pictures of fog), than keeping and using.   On  one of my most productive nights I also has a bit of a light leak that is visible on the final result.   This, and the over-squeezing of light from the 7-Eta Gemini star at least remind me of the human foibles and physical limitations associated with astrophotography that make it an interesting endeavour.