[time-nuts] Need a Watch Recommendation

[Bill Byrom]

On Wed, Mar 14, 2018, at 6:53 PM, Dr. David Kirkby wrote:
> What is the most demanding task one would use a wrist watch for? 

It depends on your job or hobby. 

During the Apollo 13 rocket burn before their emergency re-entry, Jack
Swigert used a wrist watch to time the retrorocket burn which was
manually controlled by Jim Lovell. Their normal capsule chronometer was
inoperative. This was mostly a differential (time interval) timing
measurement.
If you needed to determine your location (longitude) and all you had
was a wristwatch and a sextant (and software or a table with certain
information), the accuracy of the distance calculation would depend on
the absolute time accuracy of the watch. At the equator the longitude
error due to time error is (40,075.16 km/day) / (86,400 sec/day) =
463.8 m/sec.
Amateur astronomers need to know time accurate to about a second or
better for accurate osculation observations.
Amateur Radio nets and phone, Skype for Business, or WebEx conference
calls usually start pretty close to the scheduled time. In some cases
people start wondering if the organizer is delayed after about 15 to
30 seconds.--
Bill Byrom N5BB