This is the Rosette Nebula (Caldwell 49) in SHO with RGB stars. This was shot over the course of 8 nights from Feb 10 (2021) through Feb 23 from my Bortle 8/9 backyard in Pasadena, California. This nebula is about 5000 light years from earth and about 130 light years in diameter.

According to Wikipedia, the Rosette nebula is the official state nebula of Oklahoma which was passed into law as part of HB1292 in 2019.

More info from Wikipedia:

“A survey of the nebula with the Chandra X-ray Observatory has revealed the presence of numerous new-born stars inside optical Rosette Nebula and studded within a dense molecular cloud. Altogether, approximately 2500 young stars lie in this star-forming complex, including the massive O-type stars HD 46223 and HD 46150, which are primarily responsible for blowing the ionized bubble.[4][5] Most of the ongoing star-formation activity is occurring in the dense molecular cloud to the south east of the bubble.[6]

A diffuse X-ray glow is also seen between the stars in the bubble, which has been attributed to a super-hot plasma with temperatures ranging from 1 to 10 million K.[7] This is significantly hotter than the 10,000 K plasmas seen in HII regions, and is likely attributed to the shock-heated winds from the massive O-type stars.”

Equipment used

William Optics 132FLT w/Flat 8 (.72 reducer)

ASI 294mm camera

Filters: Astrodon 3nm Sii, Oiii, 5nm Ha, Baader RGB

iOptron CEM-70 mount

Captured with NINA, Processed with PixInsight

Integration Details

~100 subs each Ha, Oiii @360s, 121g, -10C (20 hours)

~150 subs Sii @360s, 121g, -10C (15 hours)

~ 30 subs each RGB @60s, 101g, -10C (1.5 hours)

Other capture notes

I had an issue with my sequencing on one of the Sii nights which ended up in most of the night being unguided. Amazingly the CEM70 did pretty well and I was able to use most of what I had. The only noticeable consequence was slightly elongated stars and since I was planning on removing them anyway and using and RGB starfield I integrated it and was happy. One other challenge is that the last few nights there was some moon gradient, but Adam Block’s DBE videos really helped me be more comfortable with gradient removal so it ended up better than I expected and easier that I expected to remove the bulk of it.