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04 Apr 2003

HUBBLE SPACE TELESCOPE

DAILY REPORT        # 3332

PERIOD COVERED: DOY 91

Part 4 of 4

ACS 9656

Stability of the ACS CCD: geometry, flat fielding, photometry

A moderately crowded stellar field, located ~6' West of the centre of
the cluster 47 Tuc, is observed repeatedly {every three weeks with
the WFC, every other month with the HRC} in various filters, spending
1 orbit per epoch. Different filters will be used every time, so that
over the course of the year all filters will have been employed at
least twice. The most common filters will be checked more frequently.
The same field has been observed in the course of the SMOV phase and
the positions and magnitudes of the most prominent stars have been
accurately measured. Although the field is neither a proper
astrometric nor a proper photometric standard one, the positions and
magnitudes of the objects in it can be used to monitor any local and
large scale variations in the platescale and sensitivity of the
detectors. It should be noted that for the filters which have already
been used during the SMOV phase it will be sufficient to take one
single image, without CR-SPLIT, since the exposure time is always
short {20-30 sec} and there will be so many stars that the few of
them which are affected by cosmic rays can be discarded as outliers
in the photometry. For narrow and medium band filters not exercised
on this target in the SMOV phase, however, a baseline will have to be
set. This expenditure of time will apply to the current cycle only.
At variance with the approach used in SMOV, there is no need for
large telescope slews to place the same objects on opposite sides of
the detectors, thence allowing the programme to remain compact and
efficient.  All exposure level parameters are set to their default
values, except for the amplifier gain of the WFC exposures in the
F606W band, which will be collected with the gain value of 2 for the
WFC for compatibility with the SMOV observations. The exposure time
is typically 30 seconds for the WFC, 60 sec for the HRC. No attempt
will be made to attain a predefined or the same orientation on the
sky amongst different epochs. Typically, for the WFC, five exposures
will be accommodated in one orbit. For the HRC, about 10 exposures
can be fitted within one orbit

ACS 9657

ACS Internal Flat Field Stability

The flat field stability and characterisation obtained during the
ground calibration and SMOV phases will be tested and verified
through a sub-sample of the filter set. Only internal exposures with
the calibration lamps will be required.

ACS 9673

CCD Daily Monitor

This program consists of basic tests to monitor, the read noise, the 
development of hot pixels and test for any source of noise in ACS CCD
detectors. This programme will be executed once a day for the entire
lifetime of ACS 

WFPC2 9676

POMS Test Proposal: WFII parallel archive proposal

This is the generic target version of the WFPC2 Archival Pure
Parallel program. The program will be used to take parallel images of
random areas of the sky, following the recommendations of the 2002
Parallels Working Group. 

NICMOS 9702

NICMOS Parallel Thermal Background

NICMOS Camera 2 pure parallel exposures in the F222M and F237M
filters to establish the stability of the HST+NCS+Instrument thermal
emission. This data will be compared against the already available
Camera 3 measurements in F222M which show an increased thermal
background. 

STIS 9706

STIS Pure Parallel Imaging Program: Cycle 10

This is the default archival pure parallel program for STIS during
cycle 10. 

WFPC2 9710

POMS Test Proposal: WFII backup parallel archive proposal

This is a POMS test proposal designed to simulate scientific plans.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary
reports of potential non-nominal performance that will be
investigated.) None 

COMPLETED OPS REQs: None

OPS NOTES EXECUTED:
1094-0  Clean up ACS limits, also closed on 1091-0 {at}090/2121z

                  SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq            09             09
FGS REacq            08             08
FHST Update          16             16
LOSS of LOCK

SIGNIFICANT EVENTS: None

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