Re: No Escape

[<aah@nofs.navy.mil>]

Hi, Oscar!
  The accuracy needed is often called into question on
this list.  My feeling on time, as I continue to state,
is that this is one parameter for which we can get really
good accuracy.  So, you should do the best job you
can within reason.  Certainly +/- one second at
the time you set your PC clock is easily obtainable.
You should know the drift of your clock
so that you can continue to keep this one second
accuracy at any time during the night.  If you have
NTP or equivalent, then the time will be accurate
to a few milliseconds or better.
  Do we need this accuracy?  For the minute-class
exposures, knowing time to +/- one second is probably
overkill since you have +/- 30 seconds timing error
just from the open shutter time.  For short exposures
of a few seconds (possible with the Mark IV), you
might want even better accuracy than a second.  So the
bottom line is that, since you have control over time,
make it as accurate as you can so that you can forget it
as an error source in the future.
Arne