[evla-sw-discuss] Dwell times

[Barry Clark]

We could fairly easily offer calibrator dwell times as an enhancement 
to astronomers, through obs2script.

We could have a comment card command, of the ilk
/* CDWELL <number of seconds>

Then on simple calibrator observations (that is, not reference pointing,
not fast switching), obs2script could issue a dwell time instead of
an absolute stop time.

That is, obs2script usually says
    <set up for calibrator>
    subarray.execute(<stop time of previous source>)
    <set up for next source>
    subarray.execute(<stop time for calibrator)

It could instead say, after a /* CDWELL nn card,
    <set up for calibrator>
    subarray.execute(<stop time of previous source>)
    array.waitOnSource(<stop time of calibrator>)
    <set up for next source>
    subarray.execute(min(array.tai(array.time()+nn/86400., <stop time of calib>))

array.waitOnSource() is, effectively, the routine formerly known as 
waitModcomp().

I'm not in favor of offering entire files in dwell times - the operators
will get confused if they don't know when the file will end.

A fairly easy thing to offer, but a bit of a distraction.  Is it worth 
doing?