[time-nuts] Thunderbolt Question
magnus at rubidium.dyndns.org
Mon Apr 23 21:00:42 UTC 2012
On 04/23/2012 07:01 PM, Tom Van Baak wrote:
>> I have been using a surplus Thunderbolt for about six months, and it
>> to be working fine. In January 2012, a message came up in yellow, (LEAP
>> PENDING!), I don't know what this means, but since it didn't go away
>> on Feb
>> 28, must not be leap year related.
> Hi Ed,
> Right, in this case the "LEAP" refers to a leap second, not a leap
> year. When the next leap second occurs this summer, the yellow
> warning will go away.
> As you know, leap years are used to keep "days" and "years" in
> sync, where a day is earth rotation (about its axis) and a year is
> earth revolution (around the sun). Last one was: Feb 29, 2012.
> Similarly, leap seconds are used to keep "seconds" and "days" in
> sync, where a second is now defined by atomic standards and a
> day is earth rotation. Next one is: 19:59:60 EDT, Jun 30, 2012.
> Keeping clocks in sync is a significant part of the timekeeping
> world. For example, with quartz and GPS it's easy to "discipline"
> quartz in order to steer it closer to GPS. This is done by making
> slight changes in quartz EFC voltage to change the frequency, to
> close the differential time error.
> But when it comes to orbits and planets, objects too large for us
> to change their rate, objects which have no EFC input, we have
> to resort to making artificial, bookkeeping, virtual steps in time
> instead of gradual changes in physical rate.
I thought someone finally put a cesium on the step motor keeping the ear
rotation. But no, free-wheeling like always. There is no order in this
More information about the time-nuts