awpaeth@watcgl.UUCP (Alan W. Paeth) (01/13/87)
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Yale Bright Star Catalog -- Introduction, File Formats, Notes
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This is a greatly condensed version of the public domain Yale Bright Star
Catalog, and is posted for use with C-based software tools which follow.
The posting is in four pieces, in order of increasing (dimming) apparent
magnitude. The pieces should be reassembled (by concatenation) in that order.
The original database contained about 200 bytes per item. The current version
was filtered from a version posted to the net in 1985 (From ssc-vax!bruce
3 Mar 85 06:24:32 GMT, Organization: Boeing Aerospace Co., Seattle, WA)
Because the previous net version was filtered, this is now twice reduced data.
I have kept merely three fields from Yale: right ascension, declination, and
apparent magnitude. I have also added two character codes and a optional label
to each record to make the format more useful in generating charts which might
depict entities other than stars (such as planets or Messier objects).
Comments welcome (to awpaeth@watcgl)
/Alan Paeth
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File formats:
RECORD LAYOUT
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00000000011111111112222...
12345678901234567890123...
HHMMMSS+DDMM+III12LABEL...
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FIELD LAYOUT
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Cols Type Description
1-2 I2 ra hours (Epoch 2000.0)
3-5 I3 ra minutes
6-7 I2 ra seconds
8 A1 decl sign (+ or -, never blank)
9-10 I2 decl minutes
11-12 I2 decl seconds
13 A1 mag sign (+ or -, never blank)
14-16 I3 apparent mag * 100.0
17 A1 Object code (S=star, P=planet, G=galaxy, N=nebula... etc)
18 A1 Object subcode (stars: S=single, D=double, V=variable)
(planets: M=Mercury, V=Venus...)
19-- A(n) Label (text string, eg "M31" "Polaris" or empty)
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Notes:
Owners of the original catalog can probably create columns 1-16 directly
from columns of the original Yale database, and then dummy in code "SS" for
columns 17-18. It is unfortunate that I've had to put information back into
the format, such as stellar names, because it is probably in the original.
As it is, my software presently recognizes only objects of type S (star) and P
(planet) as identified in column 17. Labels (column 19 to <cr>) are useful
in annotating prominent objects, which is done by the software. The present
code and subcode fields are almost entirely without use.
The following records were garbled as received from the net and were removed
from this condensed catalog. Their coordinates have not been checked to see
if they had represented actual objects:
050229+41050000
081334-50120000
104504-59420100
These stars had limiting magnitude below the rest of the catalog, but were
kept. Perhaps they are well known? (Alcor/Mizar, Bernhard's star?...).
053517-05230810
151419-70050820
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