Re: More on Watches

Jim Varney (
Thu, 13 Jun 1996 22:53:26 -0700

Ron Lee wrote:

>AS far as recording to 0.01 second, my time accuracy is not assumed 
>to be that good.  My reaction time is about 0.2 second and even then
>my best time accuracy is probably 0.1 second.

Yup.  "Accuracy" versus "precision."  The watch is precise to 0.01 sec,
but the human is only accurate to 0.1 or 0.2 sec at best.

I would venture that your tape recordings of "marks" and time signals
is more accurate than watch timings.  Watch timings require _two_ events
to be timed, namely the satellite measurement and the watch synchro-
nization.  This means that timing errors can be compounded.  The WWV 
on tape method has only one timed event, and is therefore more accurate.

However, this higher accuracy may be lost because on playback you have
to judge the fraction of the second your mark occurred.  Perhaps what
could be tried is recording your tape into a sound card and displayed
graphically, then measuring the position of the mark relative to each
time pip.

I have no idea if this would work.  Has anyone tried?

Good Passes,


Jim Varney      |  121^ 23' 54" W,  38^ 27' 28" N   |           Sacramento, CA
Member, SeeSat-L|            Elev. 31 ft.           |