Sat Jul 28 17:17:45 EDT 2007
Master Timekeepers Watch Clock for Nation
Above, granddaddy of all clocks in U. S. shows time in this
country and corresponding time in other parts of world
Top, tuning radio at naval observatory to receive time signal from
naval radio station at Arlington.
Center, reading tape from chronograph which checks synchronization
of clocks in thousands of a second
Left, astronomer at naval observatory operating "Zenith tune,"
which checks master clocks. It photographs stars crossing the zenith.
Chronograph records time of stars' crossing.
Above, master clock at observatory at exact noon, eastern standard
time, but its face shows seventeen o'clock, which is Greenwich time.
P. H. Tobleman points to mechanism that flashes long dash over radio
to give correct time
Margaret Stephanie Leber CCP, SCJP, SCWCD
AOPA 925383 - Amateur Radio Station K3XS - ARRL 39280 - AMSAT 32844
"The art of progress is to preserve order amid change
and to preserve change amid order."-A.N.Whitehead
More information about the time-nuts