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Software & Processing
Notes |
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CCDSoft, CCDStack,
PixInsight, Photoshop CS6
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eXcalibrator v6.0 for
(g:r), (b:r)
color balancing, using 61 stars from the Pan-STARRS database.
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PixInsight
processing includes calibration, registering, stacking, RGB
creation, gradient removal, non-linear stretching
with HistogramTransformation.
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PhotoShop for JPEG creation.
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Annotation by
Astrometry.net
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Comment |
North is to the
right.
This group of clusters
is located in the constellation Cassiopeia. From left to
right, in the bottom half of the image, are NGC 659, 663 and 654.
The respective distances are 8,200, 6,850 and 7,830 light years. All
three are very young clusters with respective ages of 20, 25 and 14
million years.
At the upper right, is
the open cluster IC 166. With an intermediate age of 1 to 1.25
million years, it is at a distance of 13 to 15,000 light years. With
its greater distance and line of sight near a dark nebula, the color
of the cluster is greatly reddened.
Perhaps the most
interesting object is the nonexistent nebula, IC 155. Charles Joseph
Etienne Wolf published his discovery of this nebula on December 30,
1893. This is thought to be one of the earliest examples of a
photographic plate defect being mistaken for a nebula. Also, it may
have been an internal reflection in Wolf's telescope.
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