The Mag 5 Star Catalog

by John P. Pratt
Mon 14 Dec 2015 (1 Water)

A new free star catalog in standard spreadsheet format which adds several features to the popular Yale Bright Star Catalog.

For a century the standard catalog of visible stars, down to magnitude 7 (visible only in binoculars), has been the Yale Bright Star Catalog. It is available on line in digital format which can be used either with a special program or can with some difficulty be imported into a spreadsheet (see Bright Star Catalog, version 5.).

The Cambridge Star Atlas
The Cambridge Star Atlas
For some time in my work there has been a need for a shorter version of the Bright Star Catalog. It is sometimes desirable to sort the catalog by magnitude, by constellation, by spectral class or other criteria. The full catalog is too large to do that on many small computers. There is much that can be deleted from it for many purposes. For example it has both 1950 and 2000 year coordinates. (Star map makers traditionally make maps attached to the earth rather than the stars so they have to be updated every 50 years!) It also has many cross-reference lists to other star catalogs.

Thus, the first step in the process used to create a light-weight version was to eliminate several columns. In the case of the stellar spectral classification column, much of the detail of emission line elements was eliminated. That version is called the Brief Bright Star Catalog in my work and can be downloaded here. It still contains all 9,110 entries, but just with about half as much information about them. Anyone wanting to restore any particular columns can easily do so from the full catalog, which can be downloaded in spreadsheet format here.

The next step was to delete stars too dim for most people to see, unless they form part of a star constellation figure. One of the desired features of this new catalog is to tie it more to constellations which are the easy way to find your way around the sky without having to resort to complicated coordinate settings on the telescope, usually requiring a computer to use. There is much to said for being able to find stars with binoculars or just the naked eye.

The criteria for deleting stars from the Brief Bright Star Catalog were the following:

Col.Contents
ABright Star (HR) Number
BStar Name
CStar Designation
DFlamsteed Number
ELetter Designation
FDouble Star Component
GConstellation Number
HConstellation Name
I2000 R.A. (hours)
J2000 R.A. (minutes)
K2000 R.A. (seconds)
LDeclination (North or South)
MDeclination (°)
NDeclination (')
ODeclination (")
PVisual Magnitude
QB-V Color Index
RU-B Color Index
SSpectral Classification
TProper Motion (R.A.)
UProper Motion (Dec.)
VDistance (light years)
WRadial Velocity (km/sec)
XSidereal Latitude
YSidereal Longitude
ZZodiac Longitude
AAZodiac Sector
Spreadsheet Columns
Hence it is called the Mag 5 Star Catalog because it contains all stars that are of fifth magnitude or brighter (rounding down). That resulted in a list of 3,922 stars, making it much more manageable than the 9,110 entries in the Bright Star Catalog.

Then several new features were added to the Mag 5 catalog:

To actually locate the stars in this catalog, it is usually necessary to look up their positions on a star map to see their positions relative to others in the sky. The spiral bound version of The Cambridge Star Atlas by Wil Tirion is recommended to be used in conjunction with these tables. The maps indicate not only the usual Bayer Greek letters and Flamsteed number designations, but also the upper and lower case English alphabet designations used extensively in the southern skies. The maps are also in color and lay flat with no stars lost in the binding. Moreover, it has the stick figure constellations figures drawn in which are extremely useful to find stars quickly, but which are not found in almost any other detailed star atlas. Other atlases are more like a map of the U.S.A. would be with only cities shown as dots without the outlines of the states drawn in.

Hopefully the Mag 5 Star Catalog will be useful to others doing star table analysis. It can be downloaded free by clicking the above "download" button. Then double click on the file, which should bring up your default spreadsheet program. Then select "comma" as the column separator. The columns are described in the table shown.