Dates:July 11, 2015 , July 13, 2015 , July 14, 2015 , July 17, 2015
Frames:
Optec 50mm B: 28x480" -25C bin 1x1
Optec 50mm G: 25x480" -25C bin 1x1
Optec 50mm L: 65x360" -25C bin 1x1
Optec 50mm R: 30x480" -25C bin 1x1
Integration: 17.6 hours
Avg. Moon age: 20.33 days
Avg. Moon phase: 8.43%
Bortle Dark-Sky Scale: 2.00
Astrometry.net job: 704934
RA center: 20h 38' 13"
DEC center: +42° 4' 15"
Pixel scale: 1.473 arcsec/pixel
Orientation: -178.334 degrees
Field radius: 0.559 degrees
Resolution: 620x456
vdB 136 is a reflection nebula in the constellation Cygnus. It locates in the north-central part of the constellation, just over 2 ° to SSW of the bright star Deneb, in the middle of a stretch of the Milky Way heavily overshadowed by the Cleft of the Swan; the best time for your observation in the evening sky falls between the months of June and November and it is much easier for observers placed in regions of the northern hemisphere of the Earth.It is rather rare for such a star to illuminate a reflection nebula. In this case it creates a rather yellow orange nebula rather than the blue color usually associated with reflection nebula. The Nebula is known as vdB 136 as well as GN 20.36.5. The field has lots of H alpha emission of warm ionized hydrogen gas. The nebula surrounding the star HD 196819, a red giant of spectral K2.5IIb having apparent magnitude 7.55; the distance, measured by a parallax value equal to 1.30 mas would be equal to 770 parsecs ( 2510 years light). Given this distance, the star with adjoining cloudiness lies within the complex of the nebulous Cleft, a short distance from the North America Nebula; in the same direction, but at a distance of more than 1500 parsecs, DR is 21, one of the systems associated with the nebulous grand star-forming region Cygnus X.
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