Re: TRMM

Ed Cannon (ecannon@mail.utexas.edu)
Sun, 13 Jun 1999 22:58:52 -0500

William B Magnusson (williamb@netc.net.au) wrote:

> Perhaps someone can clear up a little mystery that has developed. 
> ...
> 
> The mystery concerns the satellite TRMM ... 25063 97074A. None of us can see
> it. No matter how hard we look or how careful we are in assembling the data.
> ...
> 
> I have checked the latest Molczan element sets ....
> ...
>
> Why can't we see it?

I've seen TRMM at one-power quite a few times, including from 
the Univ. of Texas at Austin campus, which is in the middle 
of the city.  Most of the time the magnitude predictions I 
have are pretty accurate, especially for a payload.  (Oh, I 
just double-checked and found that I have it with a Quicksat 
intrinsic magnitude of +2.8 [= +4.3 Molczan], so that may be
one thing to take into consideration.)  

My second suggestion is that it's one of the ones that's most 
frequently reboosted, and if your elements are more than a 
couple of days old (and perhaps even less than that), you may 
be looking for it too early.  That is, if it's been reboosted 
since your elements were issued, it's running later than your 
predictions, sometimes a minute or more.  For the most 
current TRMM elsets (updated at least daily), I suggest one 
of the following:

 ftp://ftp.fc.net/pub/users/mikem/highdrg2.zip (or
  http://www.fc.net/~mikem/ftp/highdrg2.zip)
 http://www.wingar.demon.co.uk/satevo/tle/select.tle
 http://oig1.gsfc.nasa.gov/files/visible.tle

I believe that these two are updated every couple of days:

 http://celestrak.com/NORAD/elements/visual.txt (no classified)
 http://www.fc.net/~mikem/ftp/visual.tle (some classified)

Its inclination of 35 is low, but I tend to think that with
you being at -36.5, that should not be a problem.

Ed Cannon - ecannon@mail.utexas.edu - Austin, Texas, USA