There is a well-defined list of the most prominent astrophotography targets, and the Rosette nebula in Monoceros has been on this list since the beginning. It has quite significant apparent dimensions, it is quite bright, it has a well-defined structure and a lot of detailed features inside. I have already approached this target a few times, but this is the first attempt with all three narrowband filters – for hydrogen, oxygen, and sulfur elements.
Rosette nebula is also cataloged in Caldwell’s list at number 49. It is a hydrogen region located in the Monoceros region of the Milky Way. There is an NGC2244 open cluster associated with this nebulosity, and this cluster’s stars have been formed from the Rosette nebula matter. Both these targets are located about 5,000 light-years from Earth.
The NGC2244 cluster age has been estimated to be less than 5 million years. The two brightest members of the cluster are of spectral classes O4V and O5V, about 400,000 times brighter and about 50 times more massive than the Sun. NGC2244 stars are responsible for the Rosette nebula’s glow. Their radiation ionizes the elements in the nebula causing them to emit light.
Rosette is a very active stellar nursery – many Herbig-Haro objects, Bok globules, and T Tauri-type stars are present. It is much larger than the well-known Orion Nebula (130 vs. 24 light-years), but Orion Nebula is much closer to us, so its apparent size is bigger.
It is a perfect astrophotography target for medium-sized setups, where it fits as a whole into the field of view. But also large setups should be pointed there to reveal details of the Rosette nebula interior. It requires a good seeing, but the outcome will be outstanding.
Image technical data: Date: February-March 2023 Location: Nieborowice, Poland Telescope: TecnoSky 90/540 Owl triplet Corrector: TS FF/FR 0.8x Camera: QHY268M Mount: EQ6 Guiding: ASI290MM + Evoguide ED50 Exposure: 3x6 hours with Baader HSO narrowband filters. Single subframe time was 3 minutes Conditions: Bortle 6, transparency medium-good, seeing medium
