[evlatests] Pointing 7/10/05

[Ken Sowinski]

On Mon, 11 Jul 2005, Bryan Butler wrote:

> 
> and, just as a note (to the evlatests group) - the script to set up the 
> pointing file worked just fine, so it should be trivial to do pointing 
> runs with the EVLA antennas now.  if you need instructions, let me know 
> and i'll send them along.
> 
> 	-bryan
> 
> 
> On 7/11/05 09:53, Pat Van Buskirk wrote:
> > Antennas 14 and 16 were included in our pointing test on 7/10/05.
> > 
> > Antenna 16 had no data. Antenna 14 had 71 measurements with a chi-square 
> > of 29.445. The largest changes requested by the fitting model are in 
> > east-west tilt - 0.60 for A1 and 0.53 for E1. The data are in:
> > 
> > /home/yoda3/pointing/N05JUL10.PTR

actually ... /N05JUL09.PNT

The reason for the poor fit is that the evla still does
not do OTT correctly.  Restricting the solution to 
elevations less than 89 degrees and solving for tilt
azcol azzero and elzero gives a chi square of 3.1
and modest post fit residuals of 5.5 arc-sec in az and
12.5 in el.

The suggested change in tilt is abour +0.9 arc-min for
EW tilt and about +0.15 for NS tilt.  Changes to colimation
and encoder zeros were insignificant.  Solving for all terms
suggests that the perpendicularity term wants to be about -0.4
with compensating changes to azcol and azzero.  The recent
pre-renovation history for antenna 14 has the perpendicularity
term at -0.3 arc-min.

It is clear that we still have not found the right formulation
to turn PEEK tilt changes into evla tilt rotation angles.


Ken