Rosette Nebula in Hydrogen Alpha
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
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
Date: March 18 and 19, 2005
FS-102 at f6 with TOA-130 focal reducer, on the G11 Losmandy
Autoguider: SBIG STV with
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.
Post-processing: No dark, bias, or flat frames used. Auto aligned
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.
note: Graphics on this website
may not be reproduced without author permission.
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