[mmaimcal]Over the top motion and axis intersection K correction for Antenna RFP

[Al Wootten]

Folks,

Several questions have come up as the Antenna IPT moves toward its RFP 
which they want to finalize by tomorrow.  In particular the following 
question has arisen:

Specs on over-the-top:
Currently the spec is 125 degrees over the top.  My understanding is 
that over-the-top motions help in tracking objects near the zenith, and 
that it makes calculation of the 'K-correction', the intersection of the 
axes offset, more reliable.  On the present prototypes the spec on the 
intersection of the axes is that the error shall not exceed 3mm.  In the 
draft RFP this has been decreased to 2mm.  One school argues that this 
should be even tighter, 1mm.  Another school argues that the telescope 
we are building is quite stiff and that the spec is already too tight as 
it will be unlikely to vary by much.

Questions:
Can the over the top spec be relaxed to as little as 100 degrees without 
compromising determination of the offset of the intersection of the axes?

What should the spec be on the determination of the offset of the axes.

According to my notes, we discussed this on or about 14 December 1998 
but I don't have my notes of that meeting here with me in Richmond and 
apparently my workstation in Charlottesville has been turned off in 
anticipation of disaster.

Thanks for your help.

Clear skies,
Al