[evlatests] Pointing 7/10/05

[Bryan Butler]

has barry chimed in on the problem of turning PEEK tilts into EVLA tilts?

	-bryan


On 7/11/05 19:25, Ken Sowinski wrote:
> 
> 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