STIS SMOV update


1.  NUV MAMA high voltage test,  Wed. 7 May

Things were looking nominal at the intermediate voltages and for at least 4
minutes of high voltage, when telemetry was lost per the schedule.  When
reacquired, the telemetry indicated high voltage off because of the global
count rate monitor had been exceeded.   The team is studying ESS
extractions to see what actually happened during the telemetry drop out.

Meanwhile an alternate SMS132, that includes a repeat of this NUV hv test early
next week, is being readied.


2.  CCD peak-ups.  This week's failure of the 7071 peak-up was due in part to
the known elevated bias level, in the acq subarray, that skewed the
flux-weighted centroiding algorithm.   
The ~ 1-hour separation between the acq and the peak-up, on one guide star,
didn't help either.

There are plans at least to salvage the 7147 CCD Fine Alignment by
adjustment of some parameters
used in the acq algorithm so that this activity can proceed as planned in
next week's SMS.
Whether the STIS observations in the SMS139 need any adjustments to make
them work is still
under investigation.

        - Carl

biagetti@stsci.edu

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