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Re: (meteorobs) Which 'datum' to use for meteor report long...
At 09:48 AM 6/8/00 +0200, Rainer Arlt wrote:
>As the astrometric accuracy is well below 1 arc minute, the location
>should be given with better accuracy than this, say 1".
I was about to write the usual caveat about using GPS positions, that they
are artificially degraded by the US government to be as much as 2-3 seconds
off... BUT... I found that selective availability (the GPS term for that
meant the military could use highly accurate signals, while we civilians
had to make do with the degraded version) had been turned off on May 1
2000! This means my little GPS should now be accurate to less than 10
meters, rather than 100 meters. Details on the discontinuance of selective
availability can be found at:
http://www.ngs.noaadot gov/FGCS/info/sans_SA/
So now I'm going outside (at 11:30 pm) to play with my GPS. My neighbors
have given up on me, they can't figure out all the weird things I do out at
night anyway.
JB
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