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5
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Click the image for ~ 75% size
view. (2979 x
1676 - 1.37 MB)
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Instrument |
12.5" RCOS @
~ f/9 (2880 mm fl) at 0.64 arcsec/pixel. Shown at 0.85 & 2.78 arcsec/pixel. |
|
Mount |
Paramount ME |
|
Camera |
SBIG STL-11000 w/
FW8 filter wheel & AstroDon Gen-2 RGB filters. |
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Acquisition Data |
9/24/2020 & 9/25/2020 Chino Valley, AZ. with CCD Commander &
TheSkyX. AOL
guided |
|
Exposure |
|
RGB |
240 min (16 x
5 min. each) Bin 1x1 |
eXcalibrator RGB
ratios are 1.00, 1.05 & 1.20 |
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Software & Processing Notes
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-
TheSkyX, CCDStack,
PixInsight, Photoshop CS6 and Noiseware
5.
-
eXcalibrator
v6.2 for (g:r),(b:r) color balancing, using
1,515 stars from the Pan-STARRS database.
-
CCDBand-Aid to repair
KAI-11000M vertical bars.
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CCDStack to
calibrate the sub exposures.
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PixInsight
processing includes
CosmeticCorrection,
data rejection,
mean combine the sub-exposures, create the RGB image,
gradient removal and non-linear stretching with
HistogramTransformation.
-
PhotoShop for
additional background neutralization and background smoothing.
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Comment
|
Shown rotated 95°
clockwise.
Discovered by William
Herschel in 1787, NGC 7209 is an open cluster in the constellation
Lacerta. The cluster is about 3,810 light years away and is "only"
about 410 million years old. The presence of many bright bluish
stars supports the relatively young age estimate.
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