[Neocp_artsats] Sat_ID update warning

[Bill Gray]

Hello all,

    If you only use the on-line satellite tools (Sat_ID and sat_eph) on 
projectpluto.com,  you can ignore this e-mail.  The following only 
really matters if you have built those programs to run on your own 
computer,  and are using the TLEs from my GitHub site.

    If you are doing so,  you should do a 'git pull' of the 'sat_code' 
repository and run 'make',  then 'make install'.  This will get you the 
latest version of 'sat_id',  'sat_eph',  and the other tools.

    If you do not do so,  you'll find that the programs fail in a month 
or so when you get updated TLEs.  (You'll get a bunch of 'file not 
found' warnings.)

    My apologies for the nuisance,  but there _is_ a good reason for 
this change :

    A few weeks ago,  I revised Sat_ID so that it could read TLE files 
that are compressed in the gzip (.gz) format.  I've been running that 
way on my own machine and on the server that hosts on-line Sat_ID.  The 
motivation for this was that the server doesn't have a lot of space, 
and the "historical" Space-Track TLEs were eating up much of my data 
allocation.  The files compress by a factor of about three.

    Thus far,  I've not pushed the compressed files to GitHub.  When I 
do so,  older versions of Sat_ID and sat_eph will look for,  say, 
20221015.tle (Space-Track TLEs for 2022 October 15),  and fail,  not 
realizing that the data are now in 20221015.tle.gz.

-- Bill