Inclinometry & Pointing on the evening of 970422

Due to a delay in the cooling down/pumping down of the cold load on RxA2, inclinometry only started at 19:00. Mean temperature of antenna legs then was 9.8C, falling to 8.0C at end => an average of 8.9C.

Compared with the data of April 17th , when joint 1/2 was welded, changes of up to 2" are seen, principally at azimuths 72 and 169, where the wheels 3 & 2 traverse the joint 1/2. These changes may be due partly to the residual cooling of the track joint, which was not complete at the time of the inclinometry on April 17th, and partly to the elevated ambient temperature tonight - which will affect the entire track. This elevated temperature should be borne in mind when the track model is next updated.

A new track model was created and installed. The difference between this model and the previous one of 970417 is shown here .

Pointing was attempted with SCUBA thereafter, but technical problems forced us to abort and use RxA2 instead. 16 data were logged in a couple of hours, and gave rms scatters in (daz,del) of (1.3",1.9").

Conclusion : the current 7-parameter pointing model is OK.

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imc 970423