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Re: Laser Satellite Comms
At 06:31 PM 3/1/99 -0500, Dr Thomas A Clark (W3IWI) wrote:
it produces a diffraction limited
"glint" reflection. ...
~1/40000 radians = 5 arc seconds. On the ground, the
size" will be about 10 meters in diameter.
Oops. You're right. My calculated spot size was too small, as
I did the calc with straight geometry and forgot to consider
If the satellite is spinning at ~1 RPM, it
will spinning at an angular
rate of (3600 arcsec/degree)*(360 degrees/rev)/(60 sec/rev) =
21600 arcsec/sec, so the 5 arcseconds "glint" is swept out by
mirror in 5/21600 = 230 microseconds.
Aren't you missing a factor of 2 here? The spot spins around the
disco twice as fast as the disco ball spins. 5/(21600*2) = 115
In any case, I agree with your conclusion.