[mmaimcal] Re: [alma-sw-ssr] question about frequency/band switching speeds and rates

[Ed Fomalont]

Hi Bryan,

    Of course you are correct.  Maybe the limiting time for phase center 
updating is
governed by the change of primary beam on the sky.  So, the phase center 
update
should occur less than the change of the pointing by 0.1 beam (probably 
smaller
for high dynamic range work).

Ed

Bryan Butler wrote:

>
> i don't follow this.  why do you care what the magnitude of the phase 
> center change is between discrete pointings, as long as the instrument 
> is stable for each "pointing"?  it's just like "point-and-shoot" 
> mosaicing, just moving the primary beams of the antennas while you do 
> it, and going fairly fast...  now, if there is an unknown phase shift 
> across the PB, then there would be trouble, but last i knew mark had 
> worked out a way to calibrate that out...
>
>     -bryan
>
>
> On 2/4/05 13:08, Ed Fomalont wrote:
>
>> Hello all,
>>
>> 1.  Discrete changing of the phasing while doing an OTF is okay, as
>> long as the phase change for a source in the beam doesn't change by
>> more than about 10 deg between phase center updates - whatever
>> time increment this is for the highest frequency and longest baseline.
>