Book contents
- Frontmatter
- Dedication
- Contents
- Foreword
- Preface
- User Guide
- Charles Messier
- The Observations
- The Catalog
- Statistics of the Messier objects
- Visual observation of the Messier objects
- Photography of the Messier objects
- The 110 Messier objects
- M 1
- M 2
- M 3
- M 4
- M 5
- M 6
- M 7
- M 8
- M 9
- M 10
- M 11
- M 12
- M 13
- M 14
- M 15
- M 16
- M 17
- M 18
- M 19
- M 20
- M 21
- M 22
- M 23
- M 24
- M 25
- M 26
- M 27
- M 28
- M 29
- M 30
- M 31
- M 32
- M 33
- M 34
- M 35
- M 36
- M 37
- M 38
- 39
- M 40
- M 41
- M 42
- M 43
- M 44
- M 45
- M 46
- M 47
- M 48
- M 49
- M 50
- M 51
- M 52
- M 53
- M 54
- M 55
- M 56
- M 57
- M 58
- M 59
- M 60
- M 61
- M 62
- M 63
- M 64
- M 65
- M 66
- M 67
- M 68
- M 69
- M 70
- M 71
- M 72
- M 73
- M 74
- M 75
- M 76
- M 77
- M 78
- M 79
- M 80
- M 81
- M 82
- M 83
- M 84
- M 85
- M 86
- M 87
- M 88
- M 89
- M 90
- M 91
- M 92
- M 93
- M 94
- M 95
- M 96
- M 97
- M 98
- M 99
- M 100
- M 101
- M 102
- M 103
- M 104
- M 105
- M 106
- M 107
- M 108
- M 109
- M 110
- Glossary of technical terms
- Index of figures
- Index of sources
M 46
from The 110 Messier objects
Published online by Cambridge University Press: 05 August 2015
- Frontmatter
- Dedication
- Contents
- Foreword
- Preface
- User Guide
- Charles Messier
- The Observations
- The Catalog
- Statistics of the Messier objects
- Visual observation of the Messier objects
- Photography of the Messier objects
- The 110 Messier objects
- M 1
- M 2
- M 3
- M 4
- M 5
- M 6
- M 7
- M 8
- M 9
- M 10
- M 11
- M 12
- M 13
- M 14
- M 15
- M 16
- M 17
- M 18
- M 19
- M 20
- M 21
- M 22
- M 23
- M 24
- M 25
- M 26
- M 27
- M 28
- M 29
- M 30
- M 31
- M 32
- M 33
- M 34
- M 35
- M 36
- M 37
- M 38
- 39
- M 40
- M 41
- M 42
- M 43
- M 44
- M 45
- M 46
- M 47
- M 48
- M 49
- M 50
- M 51
- M 52
- M 53
- M 54
- M 55
- M 56
- M 57
- M 58
- M 59
- M 60
- M 61
- M 62
- M 63
- M 64
- M 65
- M 66
- M 67
- M 68
- M 69
- M 70
- M 71
- M 72
- M 73
- M 74
- M 75
- M 76
- M 77
- M 78
- M 79
- M 80
- M 81
- M 82
- M 83
- M 84
- M 85
- M 86
- M 87
- M 88
- M 89
- M 90
- M 91
- M 92
- M 93
- M 94
- M 95
- M 96
- M 97
- M 98
- M 99
- M 100
- M 101
- M 102
- M 103
- M 104
- M 105
- M 106
- M 107
- M 108
- M 109
- M 110
- Glossary of technical terms
- Index of figures
- Index of sources
Summary
Degree of difficulty 3 (of 5)
Minimum aperture Naked eye
Designation NGC 2437
Type Open cluster
Class II2r
Distance 4480 ly (K2005) 4490 ly (proper motion, 2002)
Size 26 ly
Constellation Puppis
R.A. 7h 41.8min
Decl. –14° 49′
Magnitude 6.1
Surface brightness –
Apparent diameter 20′
Discoverer Messier, 1771
History M 46 was discovered by Charles Messier on the 19th of February 1771, as the first object after the completion of his initial catalog of 45 objects. He described this object as “cluster of very small stars, the stars are not visible except in a good refractor, the cluster contains a bit of nebulosity.” In 1786, William Herschel found the planetary nebula NGC 2438 in this cluster. His son John later described the view: “A very fine rich cluster which fills the field. Within the cluster at its northern edge is a fine planetary nebula.” He characterized the latter as “exactly round, of a faint equable light. Has a very minute star north of center. It is not brighter to the middle nor fading away, but a little velvety at the edges.”
Leo Brenner recommended M 46 to amateur observers, about 100 years ago, with the words: “Splendid object, even for smaller telescopes. 30′ diameter, very rich and bright. Stars of 10m and lower. The cluster contains a planetary or ring-shaped nebula of 3.75′ diameter and of considerable brightness.”
Curtis, based on the photographic images, gave a characterization of M 46 which does not quite agree with its visual appearance: “a very large, bright, sparse cluster about 25′ in diameter, in which is involved the planetary nebula 2438.”
Astrophysics M 46 and M 47 form a very appealing cluster pair in the winter sky. In real space, though, they are by no means close. Rather, M 46 is supposed to be two to three times farther away than M 47. M 46 has a position 400 light-years above the galactic plane and is among the richest Messier clusters.
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- Chapter
- Information
- Atlas of the Messier ObjectsHighlights of the Deep Sky, pp. 193 - 194Publisher: Cambridge University PressPrint publication year: 2008