[mmaimcal] Re: ALMA total power integration times

[Al Wootten]

Jeff Mangum writes:
 > Hi Brian,
 > 
 > "Brian" == Brian Glendenning <bglenden at nrao.edu> writes:
 > 
 > >> If the antenna tracks perfectly, the averging you suggest would be
 > >> ok.  We toyed with the idea of doing this with the 12m system, by
 > >> allowing the observer to set the dump time, but thought that it was
 > >> too big a noose with which the observer could hang himself with.
 > 
 > Brian> Thanks.
 > 
 > Brian> I would have thought that so long as you were better than Nyquist sampling
 > Brian> the beam that all would be OK (I think 2ms would be something like 30
 > Brian> samples/beam if I got my sums right). But maybe it doesn't hurt to always
 > Brian> dump at the fastest rate - the main cost is presumably in post-processing
 > Brian> time and disk space?
 > 
 > Brian> What are the non-OTF observations that would use the TP detector, and are
 > Brian> 2ms integrations OK there as well? (We're mostly interested in the test
 > Brian> interferometer at present, but anything known about the array observing
 > Brian> modes are also interesting).
 > 
 > Brian> Cheers,
 > Brian> Brian
 > 
 > Hard to think of anything other than OTF that would require
 > millisecond-scale dump times.  We may want dumps averaged to some 10s
 > of milliseconds for things like a continuous-slew tipping mode for
 > deriving the atmospheric opacity, and some sort of continuous-slew
 > pointing mode (which will likely just be a variant of OTF).
Solar flare observations have requested short integration times such as
1 ms, I believe.

Al