Re: Geo sats.

From: Ed Cannon (
Date: Sun Mar 04 2001 - 23:07:30 PST

  • Next message: Bjoern Gimle: "Re: Flaring Geo sats."

    > How do you know where (exactly) to look?  Do you use 
    > detailed star charts of the geo arc and then predict 
    > their location in right ascension and declination?  What 
    > programs provide sat locations in RA and declination?  
    > Are there any Geo Flasher programs out there yet?
    For RA+Dec predictions I use Mike McCants' Highfly program, 
    which is available in DOS (Windows) and Linux/Unix and can 
    be downloaded via this page:

    This VSOHP page has a lot of information on programs for 
    various platforms:

    An important distinction is whether or not you want to use
    graphical predictions.  Highfly produces tabular output.
    For orbital data I use Mike McCants' geo.tle file available 

    I use star charts to get oriented on the Clarke belt, which 
    from here is centered on declination -5.  I start with Wil 
    Tirion's Bright Star Atlas, which is in coordinates of 2000.  
    When the sky is very nice, I add some star charts with stars 
    to about +7.5 which are in coordinates of 1950.  Since my 
    predictions are for 2000 RA and Dec, it's not quite perfect, 
    but having found the location with the Bright Star Atlas, by 
    comparing it with the fainter ones, it's a workable method 
    for use with 10x50 binoculars at least.  I never did decide 
    if it was better to try to scan along the entire belt or just 
    to follow one known RA+Dec area as it passed by them one by 
    one.  It was certainly necessary to become familiar with at 
    least a few asterisms on the declination, in order to be able 
    to notice something not belonging.  (It's a bit of a problem 
    when with 10x50 I can see stars fainter than +7.5, but if the 
    satellite is +6, it's soon easy to see that the stars are 
    passing by it.  By the way, I "discovered" a too-bright star 
    not on the charts, and several SeeSat folks informed me right 
    away that it was Uranus!)
    For flashing geosynchs, in order to get predictions for them, 
    I give the known ones a "fake magnitude" in the magnitude file 
    that goes with Highfly.  But you can look for them any time of
    > I'm just curious if I'll be able to see any in the Seattle 
    > area.
    Flashing geosynchs, I'd say yes, anytime of year.  Look for 
    Superbird A in the next few weeks, as it drifts from Europe over 
    here.  Some of the Gorizonts seem to flash for hours each night.  
    (Superbird A and some others flash for only a few minutes per 
    night.)  The flaring phenomenon is latitude-dependent, twice per 
    year around the equinoxes.
    Now, by the way, I should say that all of this is easier if 
    you're using a telescope!  Last October, when Mike McCants 
    returned to town and went after them with his 8-inch scope, we 
    were able to see some as faint as +10 or +11, sometimes three 
    or four in the field at once.  By then the Moon was past first 
    quarter.  Mounted binoculars would be easier also -- holding 
    binocs for two or three minutes isn't easy, in my experience.  
    But it's fun to see them!
    Ed Cannon - - Austin, Texas, USA
    Unsubscribe from SeeSat-L by sending a message with 'unsubscribe'
    in the SUBJECT to

    This archive was generated by hypermail 2b29 : Sun Mar 04 2001 - 23:10:43 PST