[time-nuts] Sidereal seconds

jmfranke jmfranke at cox.net
Fri Mar 2 16:10:38 UTC 2012


I used a PLL to convert 60Hz solar to 60Hz sidereal by multiplying by 1465 
and then dividing by 1461. The error is -1.85 seconds per day (see: Reid, 
Frank and Honeycutt, Kent;"A Digital Clock for Sidereal Time," Gleanings for 
ATMs, Sky and Telescope, July, 1976, pp.59-63).

John  WA4WDL
--------------------------------------------------
From: <aartmolsen at comcast.net>
Sent: Friday, March 02, 2012 10:48 AM
To: "Neville Michie" <namichie at gmail.com>; "Discussion of precise time and 
frequency measurement" <time-nuts at febo.com>
Subject: Re: [time-nuts] Sidereal seconds

> Forty years ago I made a sidereal rate generator that inserted 128 pulse 
> for every 46751 counted ("solar" frequency) pulses. The ratio of 
> 46879/46751 is an accurate sidereal rate, good to 1 second in about 650 
> years. I used some CD4029 presettable counters to count down from 46751 
> and used two outputs differing by 2**7 to generate the 128 pulses, So this 
> may be useful if you can come up with a method that can similarly count 
> pulses and add some.
>
>
> Aart Olsen
>
> ----- Original Message -----
> From: "Neville Michie" <namichie at gmail.com>
> To: "Discussion of precise time and frequency measurement" 
> <time-nuts at febo.com>
> Sent: Thursday, March 1, 2012 10:13:37 PM
> Subject: [time-nuts] Sidereal seconds
>
> I have a problem with two pendulum clocks that interfere with each
> other, even though they are bolted to a brick wall on bedrock
> foundations.
> A solution to this problem is to run one on mean time the other on
> sidereal time. Then I can analyse the operation of each of them.
> Now there is a problem with sidereal time that neither the GPS system
> or WWV transmit reference signals for sidereal time and the
> method of converting mean time to sidereal by calculation is
> difficult for clock synchronisation.
> A possible solution is to take mean time (from a TBolt 10MHz) and
> divide it by 9,972,695.7 to give a PPS(sid) signal that can run a
> digital clock dial
> and give one second(sid) ticks to phase the pendulum. It may be
> simpler to divide by 9,972,696 to stay with integer division and have
> an error in the
> order of a second per annum. (which we have from leap seconds anyway).
> TVB made some picDIV chips with a synch pin that do a similar task,
> but have I got the number correct? and are there other nuts that would
> like to add a sidereal clock to their clock vaults to make it worth
> while to make such a chip?
> If I set up the sidereal clock then I can use my theodolite to check
> time against the stars.
> cheers,
> Neville Michie
> Sydney
> Australia
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> 





More information about the Time-nuts_lists.febo.com mailing list