MESSIER - Messier Nebulae

Overview

The Messier Catalog of bright, extended objects was compiled by the comet-hunter Charles Messier in the 18th century. It comprised a list of 110 objects which are mostly brighter than 10th magnitude and have angular sizes from 1 to 100 arcminutes. M 102 is now generally considered to be spurious, and the object so named was actually M 101. Hence this electronic version of the Messier Catalog contains only 109 objects. The objects in the Messier Catalog are predominantly star clusters in our Milky Way galaxy, with 29 of them being globular clusters, 27 open clusters; the rest are spiral galaxies (27), elliptical galaxies (11), diffuse and planetary nebulae (10), and miscellaneous objects (5). All of the objects in the Messier Catalog are north of -35 degrees declination.

Catalog Bibcodes

1781cote.rept..227M
1985skca.book.....H

References

This version of the Messier Catalog was compiled primarily from Table III of Sky Catalog 2000.0: Volume 2, Double Stars, Variable Stars, and Nonstellar Objects, edited by Alan Hirshfeld and Roger W. Sinnott, Sky Publishing Corporation (1985).

Parameters

Name
The Messier catalog object designation.

Alt_Name
The NGC number associated with the Messier observation. Sometimes, this is blank. Please refer to notes for suspected but unconfirmed NGC notations.

RA
The Right Ascension of the object in the specified equinox.

Dec
The Declination of the object in the specified equinox.

LII
The Galactic Longitude of the object.

BII
The Galactic Latitude of the object.

Constell
A 3-character abbreviation identifying the constellation in which the object resides.

Dimension
The angular size of the object, in arcminutes. For objects that are significantly non-circular, both the major axis M and the minor axis m are listed in the form M x m.

Vmag
Most magnitudes are photoelectric visual values rounded to tenths. When these were not available, the approximate visual magnitudes were taken from M.V. Zombeck's 1982 compilation and other sources; such values have a colon, or, if originally rounded to the nearest whole value, have a '*' in the 'Vmag_Uncert' field.

Vmag_Uncert
A flag if the magnitude is uncertain. A ':' for values derived from other sources, and a '*' for values derived from other sources and rounded to the nearest whole number.

Object_Type
The object category. Di = diffuse nebula, Gb = globular cluster, OC = open cluster, Pl = Planetary Nebula, E = elliptical galaxy, Ir = Irregular Galaxy, S = Spiral Galaxy.

Notes
Notes are frequently alternative names, but there are additional notes on occasion.

Class
The Browse classification type. The classification is based on the 'Type' parameter, if one is available.

Contact Person

Questions regarding the MESSIER database table can be addressed to the HEASARC Help Desk.

Page Author: Browse Software Development Team
Last Modified: Monday, 16-Sep-2024 17:31:04 EDT