Rosette Nebula in Hydrogen Alpha

Rosette Nebula in Hydrogen Alpha
All Images Copyright Steve Cannistra

Please click here or on image for a higher resolution view.
Please click here for a wider field of view taken in 2004.

Magnitude:  4.8 (for the open cluster NGC 2244, partially seen at the top edge of this image).
Size: FOV of this image is 37' x 50'.
Distance: 5,500 light years
RA: 6h 30m 34.1s
Dec: 5 degrees 2' 55"

The Rosette Nebula is a large region of Ha emission surrounding several young, open star clusters, the most recognizable being the ladder-like formation of NGC 2244 (NGC 2244 is best seen in the center of my Rosette image from last year).  Radiation emitted by NGC 2244 blows away hydrogen gas and dust from the center of the nebula, as well as ionizes surrounding hydrogen (HII state) which subsequently emits light of wavelength 656.3 nm as it recaptures its electron.  On higher magnification, this particular field of view is full of spectacular dust lanes and dark blobs known as Bok Globules.  Bok Globules are thought to encase protostars, although their true nature remains controversial.   This image represents a 3.5 hour exposure in Ha light, taken on two consecutive nights.

Photographic Details:

Date:  March 18 and 19, 2005
Takahashi FS-102 at f6 with TOA-130 focal reducer, on the G11 Losmandy Mount.
Autoguider:  SBIG STV with e-finder.
Camera:  SXV-H9
Astronomik Ha filter (13 nm bandpass).
Exposures:  42 x 5' each, unbinned, 3.5 hours total, taken on two consecutive nights.
Conditions:  Temperature 35 degrees F; above average transparency; average seeing; generally clear.
No dark, bias, or flat frames used.  Auto aligned in MaximDL; Sigma combined using RC Sigma Reject plug in, followed by DDP in ImagesPlus (IP).  Subsequent levels and curves adjustments in Photoshop CS (16 bit format).  Final sharpening using a combination of high pass filtering followed by unsharp mask in PS.

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