Several sample database files are supplied here to get you started. These are
collections of asteroids, comets, stars, deep-sky objects, earth satellites and
spacecraft.

The sample XEphem.ad resource settings assume the database files are in this
directory. For reference, the relevant resource is:
XEphem.DBdirectory: edb



Bright stars and the Messier list as in basic.edb. The stars are from the
Yale Bright star catalogue. Only those entries with at least a
constellation name and either a common name or some sort of designator are
included. Bayer designations are given as the Greek letter spelled out (I
know -- I could have used Greek letters in X but that would break
compatibility with ephem).

Asteroids are in asteroids.edb. They are named with their sequence number
followed by their common name, if one has been assigned. The list goes to
5566.

Deep-sky entries from the Saguaro Astronomy Club database Version 6.0 are
in sac.edb. The NGC objects have been pulled out and put into ngc.edb. The
Messier objects have been commented out and moved into the basic.edb. Some
objects in the SAC database do not have well-accepted magnitudes.  These
entries are included but have special magnitude values of 99.9 or 79.9;
99.9 means no magnitude was available and 79.9 applies to dark nebulae.

Orbital elements for several spacecraft are in spacecraft.edb.

Several comets are in comets.edb and comets2.edb.

A few old sets of Shuttle elements are in shuttle.edb just to serve as a
handy example for an earth satellite to try out.

Finally, I have the entire SAO database from NSSDC broken down into 10
files in ephem format. There are a total of 258,997 entries. The complete
set is 11,332,256 bytes, 3,034,691 compressed. Look on iraf.noao.edu in
contrib/xephem/SAO.

The xephem database format remains compatible with ephem v4.28 EXCEPT that
ephem requires entries to start with an alpha character. Either add one to
all such entries in this db or modify the function nxt_db() to allow a
leading digit as well (isn't having source nice?). And, of course, ephem
does not support the earth satellite object type, E. In general, see the
Help for Objects/Data Base for a full description of the xephem database
file format.

Work on the databases is a project in itself. Authoritative contributions
welcome.
