GALLERY

Double Cluster in Perseus sometimes designated χ Persei and h Persei - NGC 869 (Melotte 13, h Persei Cluster) and NGC 884, (Melotte 14, chi Persei Cluster)

2 frames mosaic of Double Cluster in Perseus

LRGB combination (Click for a larger view 3000 x 3000 px)

Details

Double Cluster in Perseus sometimes designated χ Persei and h Persei - NGC 869 (Melotte 13, h Persei Cluster) and NGC 884, (Melotte 14, chi Persei Cluster)

Perhaps known pre-historically and cataloged 130 B.C. by Hipparcos. Recorded on November 1, 1788 by William Herschel.

NGC 869 and NGC 884 are Double Cluster in Perseus sometimes designated χ Persei and h Persei. The two clusters are separated by only a few hundred light years and probably form the core of the immense stellar association Perseus OB1. Both clusters are relatively young: NGC 884 is 3.2 million years old, and NGC 869 is 5.6 million years old. There are more than 300 blue-white super-giant stars withing both clusters, and these two clusters are also blueshifted meaning they are heading towards Earth at a speed of 22km/s. A few red supergiants are seen at considerable projected distances from the double cluster and may either belong to the background Perseus OB1 association or alternatively could represent massive stars previously ejected from the dense clusters.

North is up. The Horizontal FOV is about 74'. The objects data:

  NGC 884 NGC 869
Right Ascension 02:22:05 (h:m:s) 02:19:03.8 (h:m:s)
Declination +57:07:48 (deg:m:s) +57:08:06 (deg:m:s)
Distance 7.4 (kly) 7.1 (kly)
Visual Brightness B=6.58, V=6.1 (mag) B=5.74, V=5.3 (mag)
Apparent Dimension 18 (arc min) 18 (arc min)

Optic(s): RC 12" with Astro-Physics corrector @ f/5
Mount: ASA DDM85 Premium
Camera: ATIK 4000 - monochrome CCD – 2048 x 2048 px ; 16x16 mm; 7.4 µm x 7.4 µm
Filters: Astronomik LRGB set, SupaSlim TrueTechnology Computerized Filter Wheel
Dates/Times: 2012-11-18
Location: Remote controlled IRIDA Observatory, BG, longitude: E 24 44' 18", latitude: N 41 41' 42"
Exposure Details:

For each frame: L = 15 min, R = 15 min, G = 15 min, B = 15 min, subs. 3 min, Bin 1, Total Exposure Time - 120 min

More details: Dark and flat frames reduction
Guiding: All subexposures are unguided
Processing:

PixInsight / PS

GALLERY


All Contents copyright Velimir Popov unless otherwise noted.