The Rosette Nebula (NGC 2237-2239) in Hydrogen Alpha
Characteristics:
Magnitude: 4.8 (for NGC 2244 star cluster in center)
Size: 80' x 60'
Distance: 5500 light years
RA: 6h 31m
Dec: 4 degrees 57' 00"
Description:
The
Rosette Nebula is a winter showpiece for
astrophotographers, as
well as for visual observers at low power. This large emission
nebula is located in Monoceros and can be seen in dark locations with
the naked eye, especially if viewed through a UHC filter held up to the
sky. The nebula actually consists of several sections (NGC
2237-2239), with a central ladder like star formation known as NGC
2244. The central stars are young and newly-formed, and their
radiation is responsible for excitation of hydrogen atoms within the
nebula itself, which in turn emit light in the red. This is a
deep, 4 hour exposure in hydrogen alpha light, which reveals a great
deal of faint nebulosity on the periphery of the Rosette, as well as
filaments that extend well outside of this field of view. I
compared this image to one taken by the POSS 50 years ago and detected several stars
exhibiting proper motion.
Photographic Details:
Date: November 23, 2007.
Scope: Takahashi
FSQ106 at f5 on the Takahashi NJP
Mount.
Autoguider: SBIG ST-402 with
e-finder.
Camera: STL11K -20C.
Filters: Baader 7nm
Ha filter (50mm unmounted).
Exposures: Ha- 12 x 20'.
Total
exposure 4 hours.
Conditions: Temperature was cold, between 15-30 degrees
F over the course of the night (focusing every 40 minutes).
Post-processing:
Calibrated, aligned, and Sigma Clip combined
in Maxim, followed
by DDP
in ImagesPlus (IP). Further processing in Photoshop CS (16
bit format).
Please
note: Graphics on this website may not be reproduced without
author permission.
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