NGC 884 (also known as χ Persei) is an
open cluster
An open cluster is a type of star cluster made of tens to a few thousand stars that were formed from the same giant molecular cloud and have roughly the same age. More than 1,100 open clusters have been discovered within the Milky Way galaxy, and ...
located 7640
light year
A light-year, alternatively spelled light year (ly or lyr), is a unit of length used to express astronomical distance, astronomical distances and is equal to exactly , which is approximately 9.46 trillion km or 5.88 trillion mi. As defined by t ...
s
away in the
constellation of Perseus. It is the east component of the
Double Cluster
The Double Cluster, also known as Caldwell 14, consists of the open clusters NGC 869 and NGC 884 (often designated h Persei and χ (chi) Persei, respectively), which are close together in the constellation Perseus. Both visible to the ...
with
NGC 869
NGC 869 (also known as h Persei) is an open cluster located around 7,460 light years away in the constellation of Perseus. The cluster is around 14 million years old. It is the west component of the Double Cluster with NGC 884.
NGC 869 and 884 ...
. NGC 869 and 884 are often designated h and χ Persei, respectively.
[Some confusion surrounds what Bayer intended by these designations. It is sometimes claimed that Bayer could not have resolved the pair into two patches of nebulosity, and that Chi refers to the Double Cluster and h to a nearby star; see Stephen James O'Meara and Daniel W.E. Green, 2003, "The Mystery of the Double Cluster", ''Sky and Telescope'', Vol. 105, No. 2 (February 2003), p. 116–119. Bayer's ''Uranometria'' chart for Perseus does not show them as nebulous objects, but his chart for Cassiopeia does, and they are described as ''Nebulosa Duplex'' in Schiller's '' Coelum Stellatum Christianum'', which was assembled with Bayer's help; see Morton Wagman, ''Lost Stars'', McDonald & Woodward, 2003, , p. 240.] The cluster is about 14
million years old. Located in the
Perseus OB1 association, both clusters are located physically close to one another, only a few hundred light years apart. The clusters were first recorded by
Hipparchus
Hipparchus (; , ; BC) was a Ancient Greek astronomy, Greek astronomer, geographer, and mathematician. He is considered the founder of trigonometry, but is most famous for his incidental discovery of the precession of the equinoxes. Hippar ...
, thus have been known since antiquity.
The Double Cluster is a favorite of amateur astronomers. These bright clusters are often photographed or observed with small telescopes. Easy to find, the clusters are visible with the unaided eye between the constellations of
Perseus
In Greek mythology, Perseus (, ; Greek language, Greek: Περσεύς, Romanization of Greek, translit. Perseús) is the legendary founder of the Perseid dynasty. He was, alongside Cadmus and Bellerophon, the greatest Greek hero and slayer of ...
and
Cassiopeia
Cassiopeia or Cassiopea may refer to:
Greek mythology
* Cassiopeia (mother of Andromeda), queen of Aethiopia and mother of Andromeda
* Cassiopeia (wife of Phoenix), wife of Phoenix, king of Phoenicia
* Cassiopeia, wife of Epaphus, king of Egy ...
as a brighter patch in the winter
Milky Way
The Milky Way or Milky Way Galaxy is the galaxy that includes the Solar System, with the name describing the #Appearance, galaxy's appearance from Earth: a hazy band of light seen in the night sky formed from stars in other arms of the galax ...
. The Double Cluster was also included in the
Caldwell catalogue, a catalogue of astronomical objects for amateur observation.
[
In small telescopes, the cluster appears as a beautiful assemblage of bright stars located in a rich star field. Dominated by bright blue stars, the cluster also hosts a few orange stars that add to the visual interest. Both clusters together offer a spectacular low-magnification view.
]
References
External links
*
NGC 884 at SEDSNGC 884 at Messier45
{{DEFAULTSORT:NGC 0884
Open clusters
Perseus (constellation)
0884
Persei, Chi
Astronomical objects known since antiquity