planscan: Computing optimal directions for performing a plane scan

From: C. Bassa via Seesat-l <>
Date: Sun, 14 Feb 2016 16:42:05 +0100
Hi all,

At you'll find a Windows 7 executable that will
compute optimal directions for performing a plane scan. By providing a
TLE, an expected orbital altitude, an observing site and a time range,
this program will compute equatorial (RA/Dec) and local
(azimuth/altitude) coordinates where a satellite in the plane
specified by the TLE and at the specified orbital altitude, is
expected to be brightest.

The program works through command line arguments, so needs to be
executed from the windows command line (see

The command line options are (planscan -h):
 -t <UT Date/time>  UT Start date/time in yyyy-mm-ddThh:mm:ss [default: now]
 -c <catalog>       Input TLE catalog to use [default: classfd.tle]
 -s <site>          Site number from sites.txt [default: 4171]
 -l <length>        Search length from UT start in seconds [default: 86400 s]
 -i <NORAD>         NORAD number of satellite to select [default: 41334]
 -r <altitude>      Satellite altitude above surface in km [default: 1080 km]
 -A <elevation>     Minimum satellite elevation in degrees [default: 10 degrees]
 -S <elevation>     Maximum solar elevation in degrees [default: -6 degrees
 -h                 Shows this help

For example, the command below will compute angles for object 28888 [USA
186/05042A] from classfd.tle as seen from Greg Roberts' observing site
(COSPAR 0433). The angles are computed for an object in USA 186's
plane at an altitude of 400 km.

planscan -t 2016-02-15T00:00:00 -c classfd.tle -i 28888 -s 0433 -r 400

The output is printed to screen and saved into an output file called
scan.txt and looks like this:

Observer: Greg Roberts (0433) [-33.9406, +18.5129, 10m]
Elements: classfd.tle
Object: 28888
Start UT Date/Time: 2016-02-15T00:00:00 for 18.3333 h

UT Date/Time         R.A.      Decl.    Azi.   Alt. Range    Mag  Sun Alt. Type
                                        (deg)  (deg) (km)          (deg)
2016-02-15T18:11:00  10:15:15  00:10:00  82.7  10.4  1433.3  5.57  -7.1 Maximum
2016-02-15T18:12:00  10:14:41  00:04:06  82.6  10.7  1410.4  5.53  -7.3 Maximum
2016-02-15T18:13:00  10:14:02 -00:01:13  82.4  11.1  1387.6  5.50  -7.5 Maximum
2016-02-15T18:14:00  10:13:27 -00:08:48  82.3  11.5  1364.8  5.46  -7.7 Maximum
2016-02-15T18:15:00  10:12:46 -00:15:41  82.1  11.9  1342.0  5.43  -7.9 Maximum

Extract the zip file to a directory that is easily reachable from the
Windows command line. Check that your observing site is present in
sites.txt. If not add it, but make sure to use a unique
identifier. Note that longitudes should be negative when West of
Greenwich (USA), and positive for most of Europe. The elevation is
specified in meters. The classfd.tle catalog is recent but should be
kept updated for best results.

This code works for me on 64bits Windows 7. It was compiled with the
GNU c compiler from within Cygwin, hence the cygwin1.dll library
should exist in the same directory as the planscan executable.

This is the first version of the code so there will no doubt be users
that will have problems. Contact me offlist for help. I will post
updates in this thread when the code is changed significantly.

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Received on Sun Feb 14 2016 - 09:42:51 UTC

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