[mmaimcal] Summary of case for OSF interferometry

[Bryan Butler]

what about using the planets?  they're bright, and as long as the 
baseline is short there's plenty of brightness.  you have to take the 
source structure into account during the inversion, of course, but this 
has been done before (think of the shearing interferometer to do CSO 
holography - a neat idea, BTW).  or the SiO masers?  or maybe mark 
already considered the masers...

	-bryan

On 3/23/05 08:17, Alwyn Wootten wrote:
> Folks,
> Truth time is here--comments on the following?
> Holdaway’s simple holography simulation package in AIPS++/glish
> See https://wikio.nrao.edu/bin/view/ALMA/HoloGraphy
> Using two-element interferometric holography and the brightest compact
> celestial radio sources available, we will have enough sensitivity to
> accurately set the panels near the center of the dish, and not at the edge
> of the dish. Alternatively, using a larger cell size (0.4 m) which won't
> permit panel setting, we can very accurately confirm the surface accuracy
> of the dishes.
> Discussion: The basic question: is it worthwhile to set up a correlator at
> the OSF site to do two element holography on astronomical sources?
> Note that second antenna is followed one month later by third—time for
> interferometry at the OSF is very limited.
> NOTE: if we want to do panel settings from astronomical holography at the
> AOS, we will have to wait until we have 10 antennas.
> Alternatives:
> 	Tower holography provides setting at one elevation.
>        Photogrammetry provides measure of surface variation as f(el); has
> worked better than expected at ATF (numbers secret?)
> Out of focus beam maps have given good results at ATF (numbers secret?)
> Out of focus holography has given poor results at ATF owing to limitations
> of the evaluation receivers.  (Numbers secret?)
> Need estimate of accuracy at OSF with ALMA receivers.
> I think that the project might not establish an interferometer at the OSF
> and be just as well off.
> 
> 
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