[time-nuts] Cesium vs H Maser clocks

[Brian Kirby]

The clocks (rubidium and cesium) in the GPS satellites are also run at a 
different frequency because of their altitudes....

Also magnetic field are different on the earth and they sometimes adjust 
the "C" fields to correct for these differences.

>> Isn't the temperature the _only_ thing to correct for?
> 
> No, not at all. Read the links that I provided to see that a real
> cesium standard is not quite so simple, at least when you get
> down to the ten to the -13, -14, -15 levels. At that level there
> are all sorts of cool things that push or pull the frequency and
> need to be corrected for.
> 
>> The definition of the second is "...the duration of 9 192 631 770 
>> periods of the radiation corresponding to the transition between the 
>> two hyperfine levels of the ground state of the cesium 133 atom." (and 
>> affirmed by the CIPM in 1997 that this definition refers to a cesium 
>> atom in its ground state at a temperature of 0 K)