[evlatests] Baselines; Focus vs. elevation.

[Claire Chandler]

I take that back, I guess if there's a phase vs elevation correction that 
can be parameterized by an antenna position error in CLCOR then it's OK to 
correct for it in this way.  CLCOR only does a phase correction and 
doesn't do anything to the u,v,w based on those numbers.

Claire

On Thu, 15 Mar 2007, Claire Chandler wrote:

> Hi Vivek,
>
> It cannot be the case that the antenna positions changed when the focus
> vs. elevation corrections were turned on, so I don't understand why there
> should be two separate sets of solutions for before and after March 12.
> Rather, the positions you derive prior to March 12 have incorporated the
> phase vs elevation into the antenna positions and are incorrect.  It seems
> to me that the corrections you list as being valid post-March 12 are the
> ones to use for all D configuration data.
>
> Claire
>
> On Wed, 14 Mar 2007, Vivek Dhawan wrote:
>
>>
>> I now have solutions for EVLA antenna positions.
>>
>> They work, i.e., when applied, the phase residuals drop from
>> 100's of degrees to 10 or 20 deg, and are consistent from day
>> to day. The offsets are a bit higher than is usual for VLA
>> antennas, which makes me suspect that the phase variation from
>> the electronics is inflating the fitted offsets. However, it
>> is certainly better to apply them than not.
>>
>> Corrections applicable to data from 2007 March 12 onward are
>> in the first table, in CLCOR-ready format, offsets in m.
>> This table is for focus vs. elevation ON (corrected online).
>>
>> Though not the dominant contribution, the foc/el correction
>> changes the fitted offsets:
>>
>> dX(off) = dX(on) + 7.5 mm (error about +_ 1mm)
>> dY(off) = dY(on)
>> dZ(off) = dZ(on) + 4.5 mm
>>
>> To correct EVLA data taken with foc/el OFF - i.e. after the
>> last move and before March 12, use the second table.
>>
>>
>> -------- FOCUS vs. ELevation ON ---------------------
>> valid 2007 March 12 to 15.
>>
>> These offsets will go into the database later (tomorrow?)
>> after which they should NOT be applied in post-processing.
>>
>> task clcor; opcod 'antp'; gainver 0; gainu 0;
>> antenn 13, 0
>> clcorp  0.020,  -0.005,   0.002; go clcor; wait clcor;
>> antenn 14, 0
>> clcorp  0.020,   0.012,  -0.006; go clcor; wait clcor;
>> antenn 16, 0
>> clcorp  0.023,   0.019,  -0.015; go clcor; wait clcor;
>> antenn 17, 0
>> clcorp -0.009,  -0.015,  -0.014; go clcor; wait clcor;
>> antenn 18, 0
>> clcorp -0.002,   0.010,  -0.005; go clcor; wait clcor;
>> antenn 23, 0
>> clcorp  0.004,   0.010,  -0.010; go clcor; wait clcor;
>> antenn 24, 0
>> clcorp -0.007,   0.003,  -0.002; go clcor; wait clcor;
>> antenn 26, 0
>> clcorp -0.019,   0.012,   0.004; go clcor; wait clcor;
>>
>> ------------------------------------------------------
>>
>> -------- FOCUS vs. ELevation OFF - -------------------
>>
>> Valid XX to 2007 March 12, where XX = date of last move
>>
>> ea13 Feb13     ea14 Jan17     ea16 Jan17     ea17 Feb21
>>
>> ea18 Feb21     ea23 Jan29     ea24 Jan16     ea26 Oct18
>>
>> task clcor; opcod 'antp'; gainver 0; gainu 0;
>> antenn 13, 0
>> clcorp  0.027,  -0.005,   0.006; go clcor; wait clcor;
>> antenn 14, 0
>> clcorp  0.027,   0.012,  -0.001; go clcor; wait clcor;
>> antenn 16, 0
>> clcorp  0.030,   0.019,  -0.011; go clcor; wait clcor;
>> antenn 17, 0
>> clcorp -0.002,  -0.015,  -0.010; go clcor; wait clcor;
>> antenn 18, 0
>> clcorp  0.005,   0.010,  -0.000; go clcor; wait clcor;
>> antenn 23, 0
>> clcorp  0.011,   0.010,  -0.005; go clcor; wait clcor;
>> antenn 24, 0
>> clcorp  0.001,   0.003,   0.004; go clcor; wait clcor;
>> antenn 26, 0
>> clcorp -0.010,   0.012,   0.009; go clcor; wait clcor;
>>
>> ------------------------------------------------------
>>
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