azel.6

UNIX v6源代码 这几乎是最经典的unix版本 unix操作系统设计和莱昂氏unix源代码分析都是用的该版

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.th AZEL VI 6/3/74
.sh NAME
azel \*- satellite predictions
.sh SYNOPSIS
.bd azel
[
.bd \-d
] [
.bd \-l
] satellite1 [
.bd \-d
] [
.bd \-l
] satellite2 ...
.sh DESCRIPTION
.it 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
.bd \-d
option causes
.it azel
to ask for a date and read line|1 data (see below) from the standard
input.
The
.bd \-l
option causes
.it azel
to ask for the observer's latitude, west-longitude,
and height above sea level.
.s3
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 location)
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 magnitude level set correctly.
.s3
All times input and output by
.it azel
are GMT (Universal Time).
.s3
The satellites for which elements are maintained are:
.s3
.lp +10 10
sla,b,e,f,k	Skylab A through Skylab K.
Skylab A is the laboratory;
B was the rocket but it has crashed.
A and probably K have been verified.
.s3
.lp +10 10
cop	Copernicus I. Never verified.
.s3
.lp +10 10
oao	Orbiting Astronomical Observatory.
Seen and verified.
.s3
.lp +10 10
pag	Pageos I.
Seen and verified;
fairly dim (typically 2nd-3rd magnitude), but elements are extremely accurate.
.s3
.lp +10 10
exp19	Explorer 19; seen and verified,
but quite dim (4th-5th magnitude) and fast-moving.
.s3
.lp +10 10
c103b, c156b, c184b, c206b, c220b, c461b, c500b
.br
Various of the USSR Cosmos series; none seen.
.s3
.lp +10 10
7276a	Unnamed (satellite # 72-76A); not seen.
.s3
.i0
The element files used by
.it 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 satellite,
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 number 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 satellite.
The next three are the elements themselves
(including certain derivatives of the elements).
.sh FILES
/usr/jfo/el/* \*- orbital element files
.sh "SEE ALSO"
sky (VI)
.sh AUTHOR
J. F. Ossanna
.sh BUGS