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 _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
