LYNDS_BN (N0): Lynds' Catalog of Bright Nebulae (19921208)
FILE: lynds_bn.n0 (1125 objects)
CONTENTS: Lynds' Catalog of Bright Nebulae
DATASET: This file comes in HyperSky dataset N-1.1, version 19921208 Availability on HyperSky CD-ROM: Vol. 1 (1993)
DESCRIPTION: This datafile contains a total of 1255 bright nebulae from the
machine-readable version of Lynds' Catalog of Bright Nebulae, as provided on the NASA/GSFC Astronomical Data Center cd-rom
"Selected Astronomical Catalogs", Volume 1. The original catalog source reference is: Lynds, B. T. 1965, ApJS, 12, 163.
Lynd's catalog covers the sky from the north pole south to about -30 degrees declination, and most of his cataloged bright nebulae lie along the Milky Way.
DATA: The HyperSky datafile contains the following data from the catalog:
COORDINATES: Equatorial coordinates are stored in the datafile at equinox 2000, having been precessed from equinox 1950 coordinates in the Lynds catalog.
MAG: no magnitudes are provided in the Lynds catalog. For this reason, nebulae in this datafile will cease to appear on your display field if you set the limiting faint magnitude for ".n0" objects brighter than the default. (This is possible only when other nebulae datafiles containing magnitudes are also used.)
IDENTIFICATION: The LBN number (Lynds Bright Nebula number) is not explicitly provided in Lynds' catalog, but by convention corresponds to the order of each entry in the catalog, and thus runs from 1 to 1125. Lynds' catalog is ordered by galactic longitude; therefore the LDN numbers reflect that ordering.
COMMENTS: The comment lines contain the following information, provided if available for each nebula:
* Lynds complex numbers: Lynds included a "complex" number for many objects in his catalog, and this number is also provided. Each such number refers to an entire complex of many nebulae, and therefore multiple Lynds nebulae may have the same Lynds complex number. For example, all nebulae in the Orion region are in Lynds complex 73.
* Alternate Lynds catalog identifications: Lynds' catalog provides alternate identifications from some catalogs. These catalogs are indicated by the following abbreviations:
NGC New General Catalog
IC Index Catalog
S Catalog of H II Regions, Sharpless (1959)
C Catalog of Diffuse Galactic Nebulae, Cederblad (1956)
DG Dorschner and Gurtler (1963)
* Non-catalog identifications: These identifications are not part of the Lynds catalog, but were added from various other sources. They can include:
M: Messier catalog number.
RCW: Rodgers, Campbell & Whiteoak H-alpha emission survey number.
Common name (eg, Ring nebula).
* A line starting with "dia=", giving the angular diameter of the nebula. Units are indicated by the character after the number: A single quote (') indicates minutes of arc; a double quote (") indicates seconds of arc.
Note that some of the Lynds nebulae are very large, and all nebulae are represented by boxes even though many are long and thin. Thus, regions with many nebulae such as Cygnus can appear very confusing, with many overlapping boxes, when this datafile is used.
* A line starting with "brightness=", giving the nebula brightness based on the scale of 1(brightest) to 6(barely detectable).
* A line starting with "color=", giving the nebula color based on the following scale:
1 brighter on blue Palomar plate
2 about equal on both red and blue Palomar plates
3 brighter on red Palomar plate
4 visible only on red Palomar plate