catalog name one-line catalog description number RA(hh.mmsssss) Dec(dd.mmssss) magnitude name ...A program, starcat, exists to translate files in this format into thebinary format for faster plotting in skymap and faster searching using star. These files are then machine-, or at least byte-order-dependent, and contain the right ascension and declination in radians as 8-byte floating point numbers, magnitude with two decimal places, and optionally, the source number.
Magnitude and flux limits may be set, and the size of the plotted source
scaled by its flux. Foreground objects may be labelled and plotted as open
crosses or half-cross as well as circles. The star program may be used to
select interesting objects or print listings of positions and flux. Sources
may be identified using the cursor. A table of source size vs. magnitude may
be plotted in an arbitrary location on the display. Sources may be labelled
with their number, or if plotting from an ASCII file, their name. The
location of this label is specified in display (Tektronix) coordinates, where
coordinates less than 100 are used as offsets from the plotted source
position. The font types and sizes of the star labels may also be specified.
An optional log file may be kept which lists all of the stars plotted to the
The HST Guide Star Catalog
If the Hubble Space Telescope Guide Star Catalog CD-ROM set is mounted on the
computer as a Unix file system, skymap can plot sources directly from the
CD-ROMs. If only one CD-ROM drive is available, only the hemisphere of
interest need be mounted. As with other catalogs, magnitude limits may be set.
In addition, objects may be selected by whether or not they have been flagged
as non-stellar. Guide Stars may be plotted in the same way as the other
catalogs. If the stars are labelled, the number of the region is omitted. An
optional log file listing all Guide Stars with region and source number may be
Positions of many solar system objects, including the sun, the moon, the other
eight planets are read from auxiliary binary files. These files are defived
from the current JPL DE-130 ephemeris and are the most accurate available.
There is one file per year, so no more space is used than is neccessary, and
they reside in the directory whose pathname is specified by the parameter
EPHDIR.Planets may be plotted for any time between 1950 and 1999. Pluto's
position is made more accurate by the inclusion of software to compute the
position of its companion Charon. More than one object can be displayed, and
variation in position over time can be plotted as a series of points or a line
with tick marks. Planet characteristics are tabulated in a file called
planet.db. Rings may be plotted by selecting the appropriate data base entry.
Additional objects may be added to the planet database if ephemeris files in
a simple ASCII format
Julian date right_ascension declination distance_from_Earthexist. In this file,