Philips Atlas of the Universe

Stellar Clusters

ATLAS OF THE UNIVERSE

S

tar clusters are among the most beautiful objects in the

sky. Several are easily visible with the naked eye,

notably the Pleiades and the Hyades in Taurus, Praesepe in

Cancer, and the lovely Jewel Box in the Southern Cross;

many are within the range of binoculars or small telescopes.

In 1781, the French astronomer Charles Messier

compiled a list of more than a hundred star clusters and

nebulae – not because he was interested in them, but

because he kept on confusing them with comets, in which

he was very interested indeed. Ironically, it is by his

catalogue that Messier is now best remembered, and we

still use the numbers which he gave; thus Praesepe is M44,

while the Pleiades cluster is M45. Also in use are the NGC

or New General Catalogue numbers, given in a catalogue

by J. L. E. Dreyer in 1888; thus Praesepe is NGC2632.

The Caldwell Catalogue (C) which I compiled in 1996

seems to be coming into general use. It includes no

Messier objects.

Star clusters are of two types, open and globular. Open

or loose clusters may contain anything from a few dozen

to a few hundred stars, and have no definite structure; they

cannot persist indefinitely, as over a sufficient period of

time they will be disrupted by non-cluster stars and will

lose their identity. The stars in a cluster are of the same

age and were formed from the same interstellar cloud,

though their differing initial masses mean that they have

MCNGC Name Constellation Map Remarks

2– 7089 Aquarius 14 Globular; near ·and ‚Aquarii.

3– 5272 Canes Venatici 1 Globular; easy in binoculars.

4– 6121 Scorpius 11 Globular cluster near Antares.

5– 5904 Serpens 10 Fine bright globular.

6– 6405 Butterfly Scorpius 11 Naked-eye open cluster.

7– 6475 Scorpius 11 Fine naked-eye open cluster.

11 – 6705 Wild Duck Scutum 8 Fan-shaped; fine open cluster.

13 – 6205 Hercules 9 Brightest northern globular.

15 – 7078 Pegasus 13 Fine bright globular.

19 – 6273 Sagittarius 11 Elongated globular.

22 – 6656 Sagittarius 11 Fine globular near ÏSagittarii.

23 – 6494 Sagittarius 11 Bright open cluster near Ì.

34 – 1039 Perseus 12 Bright open cluster.

35 – 2168 Gemini 17 Naked-eye open cluster; fine.

36 – 1960 Auriga 18 Bright open cluster.

37 – 2099 Auriga 18 Bright, rich open cluster.

38 – 1912 Auriga 18 Fairly bright open cluster.

41 – 2287 Canis Major 16 Naked-eye open cluster.

44 – 2632 Praesepe Cancer 5 Famous bright open cluster.

45 – – Pleiades Taurus 17 Brightest open cluster.

46 – 2437 Puppis 19 Open cluster; rich; bright.

47 – 2422 Puppis 19 Fine rich open cluster.

48 – 2548 Hydra 7 Open cluster; not brilliant.

53 – 5024 Coma Berenices 4 Globular, near ·Comae.

54 – 6715 Sagittarius 11 Small, bright globular.

62 – 6266 Ophiuchus 10 Small, bright globular.

67 – 2682 Cancer 5 Old open cluster; bright, easy.

79 – 1904 Lepus 16 Small bright globular.

92 – 6341 Hercules 9 Large, bright globular.

93 – 2447 Puppis 19 Bright globular.

–8 66397 Ara 20 Globular; not difficult to find.

• 102 IC 2602 ıCarinae Carina 19 Fine open cluster, round ı.
  –9 62516 Carina 19 Fine open cluster, near Â.
  –8 05139 ˆCentauri Centaurus 20 Finest of all globulars.
  –9 73766 Centaurus 20 Open cluster, near Ï.
  –7 86541 Corona Australis 11 Globular; binocular object.
  –9 44755 Jewel Box Crux Australis 20 Fine open cluster, round Î.
  –8 96087 S Normae Norma 20 Open cluster; binocular object.
  –9 36752 Pavo 21 Bright globular.
  –1 4 869/884 Sword-Handle Perseus 12 Naked-eye double open cluster.
  –41– Hyades Taurus 17 Round Aldebaran.
  –9 56025 Triangulum Australe 20 Bright globular, near ‚.
  –9 5 IC 2391 ÔVelorum Vela 19 Naked-eye open cluster, round Ô.
  –– 2547 Vela 19 Naked-eye open cluster, near Î.

SELECTED STELLAR CLUSTERS ▲ The Pleiades Cluster.

The ‘Seven Sisters’ in

Taurus; the most famous

of all open clusters.Most

of the leading Pleiads

are hot and bluish white,

indicating that the cluster

is relatively young; there is

also associated nebulosity,

not difficult to photograph

but very hard to see

visually. The cluster is

not more than 50 million

years old.

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