Hi,
Her we use the following Java applet, on a computer synchronized through
NTP:
http://www.gb.nrao.edu/~jbrandt/jLSTclock/
Its precision is enoughy for our need (we're an astronomical observatory, by
the way)
About the math, the basic relation is that there is one sidereal day more in
a sidereal year than in a tropic year, which give something like
365.25/366.25 * 86400.
If you take a better value than 365.25, (365.2475 correespnd to the
Gregorian approximation, you will be closer to the value you quoted).
HTH,
Best regards,
Jean-Louis
----- Original Message -----
From: "Brian Kirby" <[email protected]>
To: "precise time" <[email protected]>
Sent: Friday, January 15, 2010 3:12 AM
Subject: [time-nuts] Sidereal time
I would like to have an electronic clock to keep sidereal time. I am
planning on using a HP 59309A, which can except an external clock of 1/5/10
Mhz.
According to Wikipedia sidereal time is 23 hours 56 minutes and 4.091
seconds - a total of 86,164.091 seconds
So 86,400 seconds for a normal "atomic defined" day divided by 86,164.091
= 1.002,737,903,89
If I set the 59309A to 10 Mhz external clock and dial a synthesizer up to
10.0273790, the unit should be able to keep sidereal time.
Is my math and theory correct ?
Brian - KD4FM
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