Hopefully this is the second-last decollimated image with my new telescope (I’m working on NGC 2175, and it should be finished before Samuel fixes my collimation.)
18.3 hours in narrowband revealed a surprising amount of S[II] emissions, and some O[III] too, right on the crest.
I would’ve bothered to collect better data, as I forgot to take the Moon into account, and my O[III] channel was afflicted by a gradient, although nothing PixInsight couldn’t solve satisfactorily. However, it was not worth spending more time than that with a decollimated telescope. The loss of detail is quite bad, but still I got a good image out of it, so I can’t complain.
IC 443 (also known as the Jellyfish Nebula and Sharpless 248 (Sh2-248)) is a Galactic supernova remnant (SNR) in the constellation Gemini. On the plan of the sky, it is located near the star Eta Geminorum. Its distance is roughly 5,000 light years from Earth.
IC 443 may be the remains of a supernova that occurred 3,000 - 30,000 years ago. The same supernova event likely created the neutron star CXOU J061705.3+222127, the collapsed remnant of the stellar core. IC 443 is one of the best-studied cases of supernova remnants interacting with surrounding molecular clouds.
(source: Wikipedia)