Hemisphere:  Northern  ·  Contains:  NGC 654
"Seahorse" dark nebula. Open Cluster NGC 654, Vdb6..., 


            Antonio F. Sánchez
"Seahorse" dark nebula. Open Cluster NGC 654, Vdb6...
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Technical card

Imaging telescopes or lenses: ASA N12 astrograph

Imaging cameras: FLI ML8300

Mounts: ASA DDM85 S-XL

Software: ASA Autoslew, Sequence...

Filters: Optec 50mm B  ·  Optec 50mm G  ·  Optec 50mm R  ·  Optec 50mm L

Accessory: FLI CFW-2-7 50mm round 7 position filter wheel

Dates:Aug. 29, 2014Sept. 1, 2014Sept. 2, 2014Sept. 3, 2014

Optec 50mm B: 21x600" -25C bin 1x1
Optec 50mm G: 16x600" -25C bin 1x1
Optec 50mm L: 52x600" -25C bin 1x1
Optec 50mm R: 19x600" -25C bin 1x1

Integration: 18.0 hours

Avg. Moon age: 6.47 days

Avg. Moon phase: 41.37%

Bortle Dark-Sky Scale: 2.00

Basic astrometry details

Astrometry.net job: 362672

RA center: 1h 44' 19"

DEC center: +61° 59' 24"

Pixel scale: 1.380 arcsec/pixel

Orientation: -179.446 degrees

Field radius: 0.574 degrees

Resolution: 620x463


It seems a Seahorse ..isn´t it ? :-)

NGC 654 is a young cluster,with an age of about 14 million years.The cluster`s 80 measured members (7th magnitude and fainter) appear in little clumps scattered across a mere 6´of sky,or 14 lightyears. Astronomers have taken keen interest in NGC 654 because of it displays nonuniform extinction across its face,with stars reddened by about 1 magnitude on average.Color excess indicates the amount of interstellar reddening suffered by the light from the star when it passes through dust in space.Data from Indian Astronomer Biman J. Medhi and colleagues (2008), show evidence for the presence of at least two layers of dust along the line of sight to the cluster, which lies at a distance of about 7800 light-years.The 7th magnitude yellow supergiant star HD 10494 is a likely member of this cluster with a recessional velocity of about 31km/sec.They estimate the distances to the two dust layers to be about 652 and 3300 light-years, placing the clouds much closer to the Sun than the cluster.The foreground dust grains,appear to be responsible,then, for the nonuniform extinction towards the cluster,whose least reddened stars lie close to the cluster center.

VdB 6 is a little reflection nebula. The star wrapped in vdB 6 is listed as HIP 8074 of magnitude 9.66, located in the Perseus arm, which gives the nebula a distinctly bluish color.

Credits: Stephen James O´Meara
"Deep-Sky Companions:The Secret Deep, Vol 4"

Italian Wikipedia



Antonio F. Sánchez
License: None (All rights reserved)

Sky plot

Sky plot


"Seahorse" dark nebula. Open Cluster NGC 654, Vdb6..., 


            Antonio F. Sánchez