BSC4 (S0): Bright Star Catalog, Fourth Edition (19930416)
FILE: bsc4.s0 (9096 stars)
CONTENTS: Bright Star Catalog, Fourth Edition, 1982
DATASET: This file comes in HyperSky dataset S-13, version 19930416. Availability on HyperSky CD-ROM: Vol. 1 (1993)
DESCRIPTION: This datafile contains the Yale BRIGHT STAR CATALOG, FOURTH EDITION (herein referred to as the BSC4), by D. Hoffleit, published in 1982 by Yale University Observatory. The BSC4 is an updated version of the earlier 1964 edition by the same author. The HyperSky file is based on the machine-readable version of the BSC4, as provided on the NASA/GSFC Astronomical Data Center (ADC) cd-rom "Selected Astronomical Catalogs", Volume 1.
BSC4 is an all-sky catalog that contains information on stars from magnitude -1.5 down to 8th, although coverage is not complete in this range (the SAO contains about 15,000 stars down to magnitude 7). The HyperSky file contains all BSC4 stars for which positions were provided; entries for some BS stars were blank (BS 95, 182, etc). For each star, the HyperSky file displays a subset of the large amount of information available in the BSC4, as discussed in the DATA section below.
The BSC4 data subset selected for HyperSky display was admittedly arbitrary, but was intended to include data thought to be of some interest to general and casual users.
DATA: The HyperSky datafile contains the following data from the BSC4 catalog:
POSITION: Right Ascension and Declination are the BSC4 2000 catalog values. The BSC4 values were recorded to an accuracy of 1 arcsec for Declination and 0.1 time second for RA. This accuracy is preserved in the HyperSky file.
MAG: the cataloged visual magnitude. BSC4 visual magnitudes are given to 2 decimal places, but stored to only one decimal place in the HyperSky datafile.
TY: the spectral type abbreviated to two letters, extracted from the full BSC4 spectral type, as provided in the comments (see below).
IDENTIFICATION: The BS("Bright Star") number. This number is also known as the HR("Harvard Revised") number.
COMMENTS: The comment lines contain the following information, provided if available for each radio source identification:
* The Henry Draper (HD) catalog number of the star. This will always be on the first comment line.
* Full BSC4 spectral type, up to 20 characters in length. Following the spectral type on the same line may be one of the following descriptive codes:
SB, SB1, SB2 - spectroscopic binary, single or double-lined spectra
* Radial velocity "rad=" If present, this comment line will begin with "rad=", followed by the radial velocity in km/sec. Positive values indicate recession; negative values indicate approach. Following the radial velocity on the same line may optionally be an descriptive code consisting of one or more of the following:
V? - radial velocity is variable or suspected variable.
SB, SB1, SB2 - spectroscopic binary, single or double-lined spectra;
O - orbital data available elsewhere.
* Rotational velocity "rot=" If present, this comment line will begin with "rot=", followed by the projected rotational velocity (v sin i) in km/sec. "rot=" may occasionally be replaced by "rot<=" or "rot<". A colon immediately following the velocity number indicates an uncertain value of v sin i.
* Multiplicty: A star noted in BSC4 as double or multiple will be flagged by the comment "mul". No further detail is provided in the HyperSky file, though identification information is available in BSC4.
* Variability: A star noted in BSC4 as variable (or possibly variable) will be flagged by the comment "var". This will be followed by the star's constellation designation (eg, R AND) from the General Catalog of Variable Stars (Kukarkin et al. 1969-1970), if one exists. Membership in other catalogs is not indicated in the HyperSky file.