NGC 7789

Common Name: Caroline's Rose

Also Known as: White Rose Cluster

Object Type: Open Cluster

Constellation: Cassiopeia

Distance from Earth: 7,600 Light years

Apparent Magnitude: 6.7

Coordinates: RA 23H 57M 24S DEC 56deg 42min 30sec

Actual Size: 50 light years in diameter

Apparent Dimensions: 16 arc-minutes

Discovered by: NGC 7789 was discovered by Caroline Herschel on November 1st, 1783 and is known as Caroline’s Rose in her honor.
Wilhelm Herschel entered the star cluster in his catalog on 18th October 1786 as VI 30 (VI = very crowded and rich star clusters). He noted: «A beautiful cluster of very compressed stars. Very rich. C. H. discovered it 1783.»

Description: NGC 7789 is an open cluster in Cassiopeia. This cluster is also known as the "White Rose" Cluster or "Caroline's Rose" Cluster because when seen visually, the loops of stars and dark lanes look like the swirling pattern of rose petals as seen from above.
Physically, it’s a rich open cluster that’s one of the oldest known: its member stars are believed to have formed around 1.6 billion years ago.
The entire group of stars covers an area of about half a degree and stands out sharply from the surrounding area.
The approximately 1,000 stars that may belong to the star cluster vary in brightness from 11 to 18 magnitudes. The distance is about 6,000 to 6,200 light-years, giving this cluster a true diameter of 50 light-years. All the stars together are about 3,000 times brighter than the Sun.
NGC 7789 has been classified by some astronomers as a star cluster that is an intermediate between an open galactic star cluster and a less concentrated globular star cluster.
A study by A. Sandage and EM Burbidge (1958) showed that it is indeed a Galactic-type cluster - but a rather unusual one: the stars are well advanced in their evolution, suggesting that the cluster is very old, older than any other well-known open star cluster.
The brightest stars are orange giants of the type K4 III with an absolute magnitude of -2.3 mag. The majority of the other bright stars are giants and subgiants.
All stars brighter than +2 mag appear to have evolved out of the main sequence of the H-R diagram. The calculated age of the cluster is about 1.5 billion years - older than most other galactic star clusters but not as old as the globular star clusters.
Messier 52 (NGC 7654) and NGC 7789 are two of a trio of great open clusters found in Cassiopeia (the other being NGC 457, the ET, or Owl Cluster), a constellation of the far northern sky that can lay claim to the title ‘the home of open clusters’.
Physically, NGC 7789 is a rich open cluster that’s one of the oldest known: its member stars are believed to have formed around 1.6 billion years ago.

Click Below Image(s) for Full Size:

NGC 7789 is circumpolar.
A 100mm (four-inch) telescope reveals around 40 to 50 stars, while looking through the eyepiece of a telescope in the 200–250mm (eight- to ten-inch) class should reveal between 100 and 150 stars scattered across an apparent diameter of around 20 arcminutes. NGC 7789 is a cluster stunner, easy to sweep up in a pair of binoculars and its myriad stars majestically grace the field of view of view of a moderate- to large-aperture telescope.

The best observation time is July to January. Throughout the autumn both are well placed and easy to find.

Platesolve

NGC 7789 Open Cluster

Imaging Details
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