Re: FW: Calipso questions

From: Gregg Hendry (
Date: Tue Mar 24 2009 - 03:51:28 UTC

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    For initial planning purposes CALIPSO passes can be predicted far
    ahead of time once you note CALIPSO is in a sun-synchronus, 1:30 PM
    ascending node, 16 day repeating ground track orbit.  This means that
    CALIPSO overflies the same ground track every 16 days and it will
    overfly points on the ground track at about the same time every time.
    CALIPSO ground tracks are about 80 miles apart at 40 degrees north.
    The time will always be around 1:30 AM local apparent time when
    CALIPSO passes overhead in darkness.    At my location CALIPSO passes
    have been within a few minutes of 2:14 AM local standard time and have
    ranged across a 5 mile wide east to west band.
    According to CALIPSO's laser is up
    and running with a new laser.   The 10 second ground track files on\\have not been
    updated yet but the 1 minute files have been.  It looks like the new
    laser is also nominally being pointed 3 degrees forward of nadir which
    puts the laser ground track about 2000 meters east of the
    sub-satellite ground track.
    Until the calibration period mentioned is complete in mid-April, I
    suspect the laser boresight will not be accurately known and ground
    track predictions could be off several hundred meters.
    Gregg Hendry
    On Sat, Mar 14, 2009 at 11:32 PM, Derek C Breit <> wrote:
    >  So Maybe someone that does flare predictions can add these passes to their
    > predictions and give me a heads up when I might see it?? I would DEFINITELY
    > 'go mobile' for this..
    > Derek
    > -----Original Message-----
    > From: Gregg Hendry []
    > Sent: Friday, February 27, 2009 11:24 PM
    > To:
    > Subject: Re: Calipso questions
    > On Fri, Feb 27, 2009 at 10:30 AM, Paul Bridges <>
    > wrote:
    > > Amateur/Lurker here in California. I have some Calipso passes over the
    > > next few months and would like to try to observe/photograph the green
    > > laser. I see that the laser is down for most of Mar/Apr due to a leak,
    > > but I have good passes in May. I would be appreciative if someone
    > > could clear up some of these questions...
    > >
    > > 1. I normally usually use Heavens-Above and HeavenSat to spot ISS,
    > > STS, and Iridiums.  Is there a better tool (using Windows) for making
    > > ground tracks?  H-Above provides little detail. SeeSat archives
    > > mention, but
    > > this appears to be only historical data, and I don't know how to make
    > > a ground track from it...........................
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