[time-nuts] Re: LTC

[tme at asteroidinitiatives.com]

On 2024-04-13 08:00, Rsec Van der leij via time-nuts wrote:
>> On 13 Apr 2024, at 13:34, Hal Murray via time-nuts 
>> <time-nuts at lists.febo.com> wrote:
>> 
>> 
>> Attila Kinali said:
>>> I guess the "off by 58.7µs" is just someone incorrectly stating the
>>> difference in relativistic shifts between a clock running on earth 
>>> and on the
>>> moon.
>> 
>> What do people on Earth do if they live in someplace like Denver that 
>> isn't at
>> sea level.
> 
> Yes, that statement annoyed me as well..
> 
> If you compare the cesium oscillator on the moon with the one on earth, 
> you'll find that the one on the moon is oscillating about 0.0006794 
> times faster. The only way to keep the two in sync is by appying leap 
> microseconds or leap seconds on a regular basis.
> 
> On the moon you can't make an Earth second by dividing your oscillator 
> by 9192631770, you need divide by 91926318480 to get a TAI-compatible 
> second, if my early morning math is correct.
> 
> If you do divide by 9192631770, you need 58.7µs per day in corrections 
> to keep in sync with Earth time. 19.8ms per year.

-58.7 microseconds / day is the mean correction for the selenocenter - 
or for an observer arbitrarily far from the Moon in the same orbit as 
the Moon.

If you include the red shift from the Moon's gravity at the lunar mean 
surface, the mean difference is  -6.481536356e-10  or = -56.0005 micro 
sec / day.

My proposal for Lunar Adjusted time is to red shift clocks on the Moon 
by the opposite amount, so that the mean rate for lunar clocks matches 
the mean rate for TAI. If that is done, the biggest orbital redshift 
correction - the equation of the center (i.e., the Moon's eccentric 
orbit) - amounts to 479.66719 nanosec over a month on average. In other 
words, Lunar Adjusted Time would match TAI to about 1/2 a microsecond.

GPS satellite clocks of course already run on an adjusted time, being 
redshifted by 4.46473e-10  or 38.5753 micro sec / day.

Regards
Marshall Eubanks

> 
> regards,