# Re: Lacrosse 2 & 3

James Nix (nixj@bellsouth.net)
Tue, 06 Jul 1999 18:18:01 -0500

```Hi Dennis,

I know...., "reality check!".  Skymap said it was due at 22 seconds
and my stopwatch, (digital to the hundredth) said 13.33.  It is obviously an
estimate but my word processor cannot make a double tilda to indicate that as
"Mathematica" can.  The error is the ubiquitous .2 to account for Human reaction
time,
perhaps it should be .2 + .2 to account for the observation and the starting of
the stopwatch at the "top" of a minute.

There's an interesting chapter in Paul Davies' "About Time" (Touchstone 96',
Ch 13 "Experimenting with Time") on human reaction time.  The message/impulse
may only take .01 sec to get to the brain but to react takes a little longer.
It also varies
from person to person. Reaction time can be less in performing "automated" and
repetitive tasks, and a .1 reaction time is common.  The now we experience is
estimated
at .04 secs.  (Paul is at the University of Adelaide, maybe Tony can get him to
add
something to the discussion?)

I often tape record my remarks on iridium tumbler observations with the NIST
clock ticking in the background and can also hear the beep of the stopwatch as I
mark
flashes.  Its interesting to note how long the NIST signals seem to take and I
can actually hear the beep of the stopwatch mark in between the NIST ticks and
estimate
whether it was a quarter to half second between time signals. I don't yet know
the
effects of the tape recording, ie whether or not it is close to actual time or a
little
slower but it is interesting to become "aware" of time spaces shorter than a
second.

Maybe nine seconds early with a .4 sec error either way would have been
appropriate :-)

Good to hear from you

Jim

Dennis Dinga wrote:
>
> >
> >Lacrosse 2 running 8.67 sec's early on:
>
> How in the world are you able to make these measurements within 1/100th of
> a second?  I need to know this trick!   :-)
>
> >Lacrosse 2
> >1 21147U 91017A   99175.38607241  .00000620  00000-0  10447-3 0    05
> >2 21147  67.9940   0.8071 0005000 193.4022 166.5978 14.69412364    06
>
> Regards, Dennis
>
>     /  /  /  /  /      * Dennis Dinga           * dennis@dinga.com
>    /--/--/--/--/       * 1024 Twin Canyon       * n6dd@amsat.org
>   /  /  /| /  /  N6DD  * Diamond Bar, CA 91765  * Tel: 909-860-1515
>          |             * USA                    * Fax: 909-860-3685
```