HUBBLE SPACE TELESCOPE - Continuing to collect World Class
Science
DAILY REPORT #4885
PERIOD COVERED: 5am July 10 - 5am July 13, 2009 (DOY
191/0900z-194/0900z)
OBSERVATIONS SCHEDULED
WFC3 11808
WFC3 UVIS Bowtie Monitor
The UVIS detector was observed during ground testing to
occasionally
exhibit flat field and dark variations with a bowtie
pattern. These
variations are most significant as ~1% flat field (gain)
variations
across the field of view. It is believed that this represents
a state or
condition into which the detector can transition for
reasons and under
circumstances which are not currently understood. It is
also very
unlikely that most science observations will determine the
state (bowtie
or no-bowtie) of the detector. Ground test data indicates
that this
state is long lived (many hours to ~one day). Hysteresis
or memory of
past light exposure is also associated with this state.
Recent evidence suggests that exposing the detector to
~200k to 500k
electrons may quench this state. This proposal obtains an
internal flat
field sequence of three exposures: one at 10x full well
with two at 0.5x
full well immediately before and after. Each exposure is
3x3 binned to
reduce the data volume required.
These visits should be scheduled 2x per day until further
direction is
provided.
FGS 11704
The Ages of Globular Clusters and the Population II
Distance Scale
Globular clusters are the oldest objects in the universe
whose age can
be accurately determined. The dominant error in globular
cluster age
determinations is the uncertain Population II distance
scale. We propose
to use FGS 1r to obtain parallaxes with an accuracy of 0.2
milliarcsecond for 9 main sequence stars with [Fe/H] < -1.5.
This will
determine the absolute magnitude of these stars with
accuracies of 0.04
to 0.06mag. This data will be used to determine the
distance to 24
metal-poor globular clusters using main sequence fitting.
These
distances (with errors of 0.05 mag) will be used to
determine the ages
of globular clusters using the luminosity of the subgiant
branch as an
age indicator. This will yield absolute ages with an
accuracy 5%, about
a factor of two improvement over current estimates.
Coupled with
existing parallaxes for more metal-rich stars, we will be
able to
accurately determine the age for globular clusters over a
wide range of
metallicities in order to study the early formation
history of the Milky
Way and provide an independent estimate of the age of the
universe.
The Hipparcos database contains only 1 star with [Fe/H]
< -1.4 and an
absolute magnitude error less than 0.18 mag which is
suitable for use in
main sequence fitting. Previous attempts at main sequence
fitting to
metal-poor globular clusters have had to rely on
theoretical
calibrations of the color of the main sequence. Our HST
parallax program
will remove this source of possible systematic error and
yield distances
to metal-poor globular clusters which are significantly
more accurate
than possible with the current parallax data. The HST
parallax data will
have errors which are 10 times smaller than the current
parallax data.
Using the HST parallaxes, we will obtain main sequence
fitting distances
to 11 globular clusters which contain over 500 RR Lyrae
stars. This will
allow us to calibrate the absolute magnitude of RR Lyrae
stars, a
commonly used Population II distance indicator.
COS 11469
COS NUV Optics Alignment and Focus
This program has stringent guide star and timing requirements.
Refer to
the observing description section for complete details.
This program determines the fine focus using NUV MIRRORA
exposures of
the same target as COS08 (program 11468 -
This program must
commence execution approximately 48 hours after completion
of visit 1 of
COS08 and as soon as possible after the uplink in visit 2
of COS08.
Three fine focus visits are executed to establish on-orbit
nominal
focus. Two detailed verification visits are executed after
the three
focus-sweep visits. Approximately 48 hours after each
odd-numbered visit
an uplink of new information is required.
ACS 11465
ACS CCD monitoring and calibration for WFC
This program is a smaller version of our routine CCD
monitoring program,
designed to run throughout SMOV, after which our regular
Cycle 17
proposal will begin. This program obtains the bias and
dark frames
needed to generate reference files for calibrating science
data, and
allows us to monitor detector noise and the growth of hot
pixels.
WFC3 11447
WFC3 IR Dark Current, Readnoise, and Background
This proposal obtains full-frame, four-amp readout images.
Un-illuminated internals are taken at regularly spaced
intervals
throughout SMOV in order to assess and monitor readnoise
and dark
current (of both light-sensitive pixels and reference
pixels), and bad
(warm, hot, dead, variable) pixels. In addition, externals
aimed at
fields with sparse stellar density are taken to measure
diffuse
background light.
This program corresponds to WFC3-34.
WFC3 11446
WFC3 UVIS Dark Current, Readnoise, and CTE
This proposal obtains full-frame, four-amp readout bias
and dark frames
at regularly-spaced intervals throughout SMOV in order to
assess and
monitor dark current, bad (warm, hot, dead) pixels, and
readnoise. . In
addition, a set of internals using the WFC3 calsystem are
taken to
provide a baseline CTE measurement.
WFC3-33
WFC3 11434
WFC3 UVIS Fine Alignment
The corrector mechanism will be used to bring the UVIS
channel of WFC3
into optimal alignment with the OTA using analysis of star
images over
the field. Two visits are required; corrector offsets will
be uplinked
after each visit via realtime command.
This proposal is activity id WFC3-21
WFC3 11432
UVIS Internal Flats
This proposal will be used to assess the stability of the
flat field
structure for the UVIS detector. Flat fields will be
obtained for all
filters using the internal D2 and Tungsten lamps.
This proposal corresponds to Activity Description ID WF19.
It should
execute only after the following proposals have executed:
WF08 - 11421
WF09 - 11422 WF11 - 11424 WF15 - 11428
STIS07 11404
CCD Dark and Bias Monitor for SMOV4/Cycle 17 Activity
STIS-07
Monitor the darks for the STIS CCD. Monitor the bias in
the 1x1, 1x2,
2x1, and 2x2 bin settings at gain=1, and 1x1 at gain = 4,
to build up
high-S/N superbiases and track the evolution of hot columns.
ACS 11398
UV Sensitivity, Geometric Distortion and Flat Field
Verification for SBC
NGC604 is observed to provide a secondary check on UV
sensitivity, and a
primary verification of geometric distortion and flat
fields following
the similar calibrations done in ACS/CAL-10722. Exposures
are obtained
on a 10x10 arcsec dither box, and the geometric distortion
is
established using the previously available HRC calibration
of this field
as a reference.
Internal flats using the deuterium lamp are obtained in
the full suite
of SBC filters and the prisms, this follows from
ACS/CAL-11052.
ACS 11374
CCD Flat Field Stability (Internal Tungsten Lamps)
The stability of the CCD flat fields will be investigated
using the
internal tungsten calibration lamps and the standard
filter subset
(F435W, F625W, F814W, and F850LP). High signal
observations will be used
to assess the stability of the pixel-to-pixel flat field
structure
(P-flat) and to verify the position of the dust motes. The
stability of
the low-frequency flat fields (L-flats) will be assessed
by comparing
internal exposures obtained just prior to the ACS failure
in January
2007 and immediately following the ACS repair in August
2008. This is
activity number ACS-11.
ACS 11369
ACS CCD functional test for WFC
During the ACS Repair (ACS-R) conducted during Hubble
Servicing Mission
4 (SM4), astronauts will install a CCD Electronics Box
Replacement
(CEB-R) and Low-Voltage Power Supply Replacement (LVPS-R).
A rudimentary
aliveness/functional test (AT/FT) will be conducted
on-orbit during SM4.
Shortly after SM4, the more comprehensive CCD function
test (FT) defined
in this program will be conducted as part of SMOV. This
program is
modeled after the original CCD functional test (HST
program 9005, PI
Mark Clampin) conducted following the initial installation
of ACS during
Hubble Servicing
FLIGHT OPERATIONS SUMMARY:
Significant Spacecraft Anomalies: (The following are
preliminary reports
of potential non-nominal performance that will be
investigated.)
HSTARS:
11927 - Following successful real-time commanding OPS
REQ#18609-2 (Transition from Suspend to Operate
and Check MIE) STIS
suspended during "Dump RAM section of
MIE" real-time commanding. Status
Buffer message, STIS 100 (MIE Jump to operate
failed) parameter=100
(octal) was received at 191/16:44:18.
COMPLETED OPS REQUEST:
18609-2 - Recover STIS from Suspend @ 191/1644z
18612-0 - WFC3 UVIS Corrector Adjustment @ 191/1905z
18613-0 - STIS Memory Dump after Suspend @ 191/2048z
18614-0 - GenSlew for proposal 11469 (slot # 5) @
192/1507z
18615-0 - GenSlew for proposal 11469 (slot # 6) @
192/1509z
18616-0 - GenSlew for proposal 11469 (slot # 1) @
192/1511z
18617-0 - GenSlew for proposal 11469 (slot # 2) @
192/1539z
18618-0 - GenSlew for proposal 11469 (slot # 3) @
192/1541z
18619-0 - GenSlew for proposal 11469 (slot # 4) @
192/1542z
18568-1 - LBBIAS Updates for extended Gyro Guiding
Intervals @ 192/2230z
18620-1 - GenSlew for proposal 11492 (slot # 5) @
193/1124z
COMPLETED OPS NOTES: (None)
SCHEDULED SUCCESSFUL
FGS GSAcq 21 21
FGS REAcq 07 07
OBAD with Maneuver 20 20
SIGNIFICANT EVENTS:
STIS Suspended during recovery attempt on July 10
During Ops. Request 18609 to recover STIS to Operate mode,
STIS again
suspended due to a STIS STB 100 "Invalid CS FSW Mode
for More than 10
Minor Frames". This occurred after STIS was
transitioned from Suspend to
full Operate mode (mechanism and CEB). Error was reported
during
attempted transfer of MIE RAM Memory to STIS CS Buffer RAM
using macro
OMIE2RAM. Payload FSW, STScI and SI SE have started
investigation.