performance check after kevlar cables tensioned, tertiary moved.
The turret floor re enforcing and the kevlar cable
tensioning were completed on 08apr04. A quick calib run (transit to set)
was done using 3C138 (B0518+165) using lbw. On 09apr04 the
tertiary was resurveyed into position and then a number of sources were
tracked rise to set using lbw and sbn.
Fig 1. System performance and pointing errors after
kevlar cables, before tertiary moved. This was taken with lbw.
There is ramp in azimuth error that is a function of za (-12 asecs to +12asecs
low to high za.)
Fig 2. system performance and pointing errors after
kevlar cables and after tertiary moved. This data was taken with lbw
and sbn.The tertiary was moved .25 inches down and .25 inches toward the
secondary before this data was taken. There is now a -16 asecs offset in
za. The azimuth error ramp with za is not longer obvious.
Fig 3. system performance and pointing errors after
kevlar cables, tertiary moved, and with 17 asec za offset to fix above
offset. There was no change to the azimuth terms. This was done with lbw
on 10apr04 in the morning. The za error if small. The az error gets up
to 20 asecs.