|
Exposure |
SII 480
min. (16 x 30 min. bin 2x2)
Hα
510 min. (17 x 30 min. bin 2x2)
OIII 570 min. (19 x 30 min. bin 2x2)
RGB 180 min. (
4 x 15 min each, bin 2x2)
SII:Hα:OIII
mapped to RGB with an overlay of RGB stars colors.
Click
here for an RGB color version.
Click
here for an Ha filtered b/w image. |
|
Software |
-
CCDSoft, CCDStack,
Photoshop CS w/ the Fits Liberator plugin. Noel Carboni's actions.
-
eXcalibrator for (b-v), (v-r) star color calibration, using 7
stars from the NOMAD1 database.
-
PixFix32 (pre-beta) to
repair hot/cold pixels and column defects.
-
CCDStack to calibrate,
register, normalize, data reject, combine the sub exposures.
-
PhotoShop for color
combine &
on-linear stretching.
|
|
Comment |
North ~ to the left.
The image is rotated 70° CCW
DWB-111, the Propeller Nebula, is an emission nebula in the
constellation Cygnus. Astronomers seem to have more questions than
answers, regarding this nebula. The origin of the peculiar structure
is still completely unknown. The nebula's distance and source of
excitation are also undetermined. DWB-111 mass is believed to be quite
low, probably less than 50 solar masses. Obscuring dust is closely
associated with the nebula, but seems to occur mostly in front of
it.
These false color
images were acquired with SII, Ha and OIII filters mapped to the RGB
channels respectively. The colors of top image more closely follow
the Hubble Palette, with the color channels pretty much stretched to
equal levels. The presence of sulfur, hydrogen and oxygen are
clearly shown. Red indicates the presence sulfur, green hydrogen and
blue oxygen. With no color manipulation, the image would be
basically green, due to the dominance of hydrogen.
The lower image was
further processed to produce the orange and blue colors, made
popular by the Hubble Imaging Team.
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