Diffuse Nebula NGC 2237 (Sh2-275, LBN 948-9, The Rosette Nebula) and Open Cluster NGC 2244 in Monoceros
HaR-G-OIIIB plus SIIHaOIII (Click for a larger view 1800 x 1800 px)
HaR-G-OIIIB - mapped in pink (Click for a larger view 1800 x 1800 px)
SII-Ha-OIII - nebula in mapped HST color (Click for a larger view 1800 x 1800 px)
Ha-HaOIII-OIII - bicolor technique with a synthetic green (Click for a larger view 1800 x 1800 px)
Details
Diffuse Nebula NGC 2237 (Sh2-275, LBN 948-9, The Rosette Nebula) and Open Cluster NGC 2244 in Monoceros
Discovered by John Flamsteed about 1690.
The Rosetta Nebula is a vast cloud of dust and gas, extending over an area of more than 1 degree across. Its parts have been assigned different NGC numbers: 2237, 2238, 2239, and 2246. Within the nebula, open star cluster NGC 2244 is situated, consisted of the young stars which recently formed from the nebula's material, and the brightest of which make the nebula shine by exciting its atoms to emit radiation.
Open cluster NGC 2244 was discovered by Flamsteed about 1690. The nebula, however, was not even seen by William Herschel (who found the cluster); its different parts were discovered only by John Herschel (NGC 2239), Marth (NGC 2238), and Swift (NGCs 2237 and 2246); note that while now these numbers are used for describing parts of the diffuse nebula, their original NGC description is quite different:
NGC 2237 pretty bright, very very large, diffuse
NGC 2238 faint star in nebulosity
NGC 2239 star of mag 8 in large, poor, bright cluster
NGC 2246 extremely faint, large, irregularly round, extremely difficult
The Horizontal FOV is about 110'. The image almost centered at:
| |
NGC 2237 |
NGC 2244 |
| Right Ascension |
06 : 32.3 (h:m) |
06 : 32.4 (h:m) |
| Declination |
+5 : 03 (deg:m) |
+4 : 52 (deg:m) |
| Distance |
5.5 (kly) |
5.5 (kly) |
| Brightness |
- |
4.8 (mag) |
| Apparent Dimension |
80x60 (arc min) |
24 (arc min) |
| Seeing: |
Pickering 7 rating - Good |
| Optic(s): |
APO 90/600+WO field flatener @ f/4.9 |
| Mount: |
CGE equatorial |
| Camera: |
Artemis Art 4021 - monochrome cooled CCD camera – 2048 x 2048 px ; 16x16 mm; 7.4 µm x 7.4 µm |
| Filters: |
Astronomik Ha, OIII, SII, R, G, B set, Truetek Computerized Filter Wheel |
| Dates/Times: |
2011-11-01 |
| Location: |
Rozhen Observatory, BG, longitude: E 24 44' 18", latitude: N 41 41' 42" |
| Exposure Details: |
Ha = 50 min, OIII = 50 min, SII = 50 min, (Bin 1), R = 20 min, G = 20 min, B = 20 min ( Bin 2) Subexposures: HaOIIISII = 10 min, RGB = 5 min, Total Exposure Time - 210 min |
| More details: |
Dark frames reduction |
| Guiding: |
Starlight Xpress Lodestar Autoguider on Celestron 11" Schmidt Cassegrain |
| Processing: |
PixInsight / PS |
GALLERY |
