Re: [amsat-bb] Calculating Astronomical Sunset

[John Wright <g4dmf@xxxxxxxxxxx>]

At 18:38 27/11/2001 -0500, you wrote:
>Hi all,
>  While trying to get a look at Starshine, I was trying to determine how
>long the bird would be in sunlight while my QTH was in the dark. In the
>past I've usually figured on a couple of hours for most LEO satellites.
>But it got me wondering if there is a formula to determine, more
>accurately, how long a satellite will be in sunlight after sunset on the
>ground.
>  Of course the altitude of the bird would be a factor, as well as the
>circumference of the earth. But it's been 30 years since I got out of
>college and I've forgotten most of my physics and geometry. Any ideas?
>  Thanks in advance. 73 de Doug KA8QCU
>
If you use a program like LOGSAT and probably quite a few others, the 
prediction function has a radio/visual tick box, if you select visual, it 
only shows times when you are in darkness and the satellite is still 
illuminated, It will give predictions for as far ahead as the keps are good 
for.

If you have a tracking prog that shows sunlight area, then whilst YOU are 
in the dark section, but the footprint of the satellite still crosses the 
light area, then it is illuminated.

I can recommend LOGSAT  as a very usefull tracking prog. No connection with 
the company!, just a satisfied customer.



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      G4DMF  QTHR   IO93ha
      Amsat-UK Member 5372
          g4dmf@amsat.org
        g4dmf@g4dmf.co.uk
      http://www.g4dmf.co.uk
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