NAME
azel - satellite predictions
SYNOPSIS
azel [ -d ] [ -l ] satellite1 [ -d ] [ -l ] satellite2 ...
DESCRIPTION
Azel predicts, in convenient form, the apparent trajectories
of Earth satellites whose orbital elements are given in the
argument files. If a given satellite name cannot be read,
an attempt is made to find it in a directory of satellites
maintained by the programs's author. The -d option causes
azel to ask for a date and read line 1 data (see below) from
the standard input. The -l option causes azel to ask for
the observer's latitude, west-longitude, and height above
sea level.
For each satellite given the program types its full name,
the date, and a sequence of lines each containing a time, an
azimuth, an elevation, a distance, and a visual magnitude.
Each such line indicates that: at the indicated time, the
satellite may be seen from Murray Hill (or provided loca-
tion) at the indicated azimuth and elevation, and that its
distance and apparent magnitude are as given. Predictions
are printed only when the sky is dark (sun more than 5
degrees below the horizon) and when the satellite is not
eclipsed by the earth's shadow. Satellites which have not
been seen and verified will not have had their visual magni-
tude level set correctly.
All times input and output by azel are GMT (Universal Time).
The satellites for which elements are maintained are:
sla,b,e,f,kSkylab A through Skylab K. Skylab A is the labo-
ratory; B was the rocket but it has crashed. A
and probably K have been verified.
cop Copernicus I. Never verified.
oao Orbiting Astronomical Observatory. Seen and veri-
fied.
pag Pageos I. Seen and verified; fairly dim (typi-
cally 2nd-3rd magnitude), but elements are
extremely accurate.
exp19 Explorer 19; seen and verified, but quite dim
(4th-5th magnitude) and fast-moving.
c103b, c156b, c184b, c206b, c220b, c461b, c500b
Various of the USSR Cosmos series; none seen.
1
7276a Unnamed (satellite # 72-76A); not seen.
The element files used by azel contain five lines. The
first line gives a year, month number, day, hour, and minute
at which the program begins its consideration of the satel-
lite, followed by a number of minutes and an interval in
minutes. If the year, month, and day are 0, they are taken
to be the current date (taken to change at 6 A.M. local
time). The output report starts at the indicated epoch and
prints the position of the satellite for the indicated num-
ber of minutes at times separated by the indicated interval.
This line is ended by two numbers which specify options to
the program governing the completeness of the report; they
are ordinarily both ``1''. The first option flag suppresses
output when the sky is not dark; the second supresses output
when the satellite is eclipsed by the earth's shadow. The
next line of an element file is the full name of the satel-
lite. The next three are the elements themselves (including
certain derivatives of the elements).
FILES
/usr/jfo/el/* - orbital element files
SEE ALSO
sky (VI)
AUTHOR
J. F. Ossanna
BUGS
2