On 7/8/2015 4:22 AM, N_Cook wrote:
On 07/07/2015 19:37, Jeff Liebermann wrote:
On Sat, 04 Jul 2015 13:10:22 -0400, Phil Hobbs
wrote:

On 6/27/2015 10:26 PM, wrote:
I've got the best time sync source of all, courtesy
the NIST and WWVB!

Second best. They adjust those ones to match that yellow thing up in
the sky.
Cheers
Phil Hobbs

Does the NIST use a sundial for a primary time standard? I realize
that budget cuts have necessitated economy measures, this seems a bit
extreme.

(We just had a leap second.)

Yep. That felt good. I got one second of extra sleep.



The new generation of atomic clocks, accurate to 1 second in 15 billion
years,supposedly - how do they know , without a more accurate clock than
that to check it against?

It's a specific case of a very general problem, namely how to estimate
and control systematic errors in a measurement. Generally speaking, if
your hydrogen maser and your neighbour's caesium clock and your Russian
brother-in-law's Bose-Einstein condensation agree, you can be pretty
confident. Otherwise it's a real headache.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC
Optics, Electro-optics, Photonics, Analog Electronics

160 North State Road #203
Briarcliff Manor NY 10510

hobbs at electrooptical dot net
http://electrooptical.net