[mmaimcal] Re: ALMA total power integration times

[Jeff Mangum]

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).

Cheers,

Jeff