AZEL(VI)                     9/22/73                     AZEL(VI)


     azel - obtain satellite predictions


     azel satellite ...


     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.

     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  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


     All times input and output by azel are GMT (Universal Time).

     The satellites for which elements are maintained are:

     sla, ... sllSkylab A through Skylab L.  Skylabs A and B  are

               the  laboratory  and  its rocket respectively; the

               remainder are various other objects attendant upon

               its  launch  and subsequent activities.  A, B, and

               probably K have been sighted and verified.

     cop        Copernicus I. Never verified.

     oao        Orbiting  Astronomical  Observatory.   Seen   and


     pag        Pageos  I.   Seen  and   verified;   fairly   dim

               (typically  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.

     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

     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).

     The author should be consulted for more information.


     /usr/jfo/el/* - orbital element files


     sky (VI)


     J. F. Ossanna