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Daily 3528



 
 
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Old January 12th 04, 04:28 PM
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Default Daily 3528

HUBBLE SPACE TELESCOPE

DAILY REPORT # 3528

PERIOD COVERED: DOYs 9-11/2004

OBSERVATIONS SCHEDULED

ACS 9984

Cosmic Shear With ACS Pure Parallels

Small distortions in the shapes of background galaxies by foreground
mass provide a powerful method of directly measuring the amount and
distribution of dark matter. Several groups have recently detected
this weak lensing by large-scale structure, also called cosmic shear.
The high resolution and sensitivity of HST/ACS provide a unique
opportunity to measure cosmic shear accurately on small scales. Using
260 parallel orbits in Sloan textiti {F775W} we will measure for the
first time: beginlistosetlength sep0cm setlengthemsep0cm setlength
opsep0cm em the cosmic shear variance on scales 0.7 arcmin, em the
skewness of the shear distribution, and em the magnification effect.
endlist Our measurements will determine the amplitude of the mass
power spectrum sigma_8Omega_m^0.5, with signal-to-noise {s/n} ~ 20,
and the mass density Omega_m with s/n=4. They will be done at small
angular scales where non-linear effects dominate the power spectrum,
providing a test of the gravitational instability paradigm for
structure formation. Measurements on these scales are not possible
from the ground, because of the systematic effects induced by PSF
smearing from seeing. Having many independent lines of sight reduces
the uncertainty due to cosmic variance, making parallel observations
ideal.

STIS/CCD 9981

The Ultra Deep Field - STIS parallels

We propose to obtain slitless spectroscopy of objects in the GEMS and
GOODS area around the UDF.

WFPC2 9980

The Ultra Deep Field - WFPC2 Parallels

The ACS Ultra Deep Field {UDF} is a survey carried out by using
Director's Discretionary time. The main science drivers are galaxy
evolution and cosmology. The primary instrument is the Advanced Camera
for Surveys but WFPC2, NICMOS, and STIS will also be used in pure
parallel mode. The data will be made public. The UDF consists of a
single ultra-deep field {410 orbits in total} within the CDF-S GOODS
area. We request a modification of the default pure parallel programs.
Rather than duplicate the redder bands which will be done much better
with ACS, we propose to observe in the near-ultraviolet F300W filter.
These data will enable study of the rest-frame ultraviolet morphology
of galaxies at 0z1, allowing determination of the morphological
k-correction and the location of star formation within galaxies, using
a sample that is likely to be nearly complete with multi-wavelength
photometry and spectroscopic redshifts. The results can be used to
interpret observations of higher redshift galaxies by ACS.

NIC3 9979

The Ultra Deep Field - NICMOS Parallels

This is a plan to manage the NICMOS pure parallels of the ACS Ultra
Deep Survey. We will obtain a mix of F110W and F160W images along
sight-lines within the mosaiced ACS fields of the CDF-S GOODS and GEMS
surveys, with these sight-lines enabling an examination of the space
density and morphologies of the reddest galaxies.

ACS/CCD/WFC 9978

The Ultra Deep Field with ACS

The ACS Ultra Deep Field {UDF} is a survey carried out by using
Director's Discretionary time. The main science driver are galaxy
evolution and cosmology. The primary instrument is the Advanced Camera
for Surveys but WFPC2 and NICMOS will also be used in parallel. The
data will be made public. The UDF consists of a single ultra-deep
field {410 orbits in total} within the CDF-S GOODS area. The survey
will use four filters: F435W {55 orbits}, F606W {55 orbits}, F775W
{150 orbits}, and F850LP {150 orbits}. The F435W {B} and F606W {V}
exposures will be one magnitude deeper than the equivalent HDF
filters. The F775W {I} exposure will be 1.5 magnitude deeper than the
equivalent HDF exposure. The depth in F775W and F850LP is optimized
for searching very red objects - like z=6 galaxies - at the detection
limit of the F850LP image. The pointing will be RA{J2000}=3 32 40.0
and Decl.{J2000}=-27 48 00. These coordinates may change slightly due
to guide star availability and implementation issues. We will attempt
to include in the field both a spectroscopically confirmed z=5.8
galaxy and a spectroscopically confirmed type Ia SN at z=1.3. The
pointing avoids the gaps with the lowest effective exposure on the
Chandra ACIS image of CDFS. This basic structure of the survey
represents a consensus recommendation of a Scientific Advisory
Committee to the STScI Director Steven Beckwith. A local Working Group
is looking in detail at the implementation of the survey.

FGS 9969

FGS Astrometry of the Extrasolar Planet of Epsilon Eridani

We propose observations with HST/FGS in Position Mode to determine the
astrometric elements {perturbation orbit semimajor axis and
inclination} of the candidate extra-solar planet around the K2 V star
Epsilon Eridani that has been detected by Doppler spectroscopy. These
observations will also permit us to determine the actual mass of the
planet by providing the sin{i} factor which can not be determined with
the radial velocity method. High precision radial velocity {RV}
measurements spanning the years 1980.8--2000.0 for the nearby {3.22
pc} star Epsilon Eri show convincing variations with a period of ~ 7
yrs. These data represent a combination of six independent data sets
taken with four different telescopes. A least squares orbital solution
using robust estimation yields orbital parameters of period, P = 6.9
yrs, velocity K- amplitude = 19 m/s, eccentricity e = 0.6, projected
companion mass M_B sin{i} = 0.83 M_Jupiter. An estimate of the
inclination yields a perturbation semi-major axis, Alpha = 0arcs0022,
easily within the reach of HST/FGS astrometry.

ACS/HRC/WFC 9919

The Morphological, Photometric, and Spectroscopic Properties of
Intermediate Redshift Cluster Galaxies:

New and fundamental constraints on the evolutionary state of high
redshift clusters will be made by obtaining deep, multiband images
{SDSS r, i, z} over the central 1.5 Mpc regions of seven distant
clusters in the range 0.76 z 1.27. The ACS data will allow us to
{1} definitively establish the morphological composition and star
formation rates as functions of clustercentric radius, local density,
x-ray luminosity {obtained from accompanying Chandra, and XMM data},
{2} explore the relationship between substructure, kinematics, and
morphology, {3} strongly constrain the galaxy merger frequency and the
origins of elliptical and S0 galaxies, {4} measure the mass
distribution independently from the light {via gravitational lensing}
enabling comparisons with kinematically derived masses, and {5} study
the evolution of the structure of the brightest cluster members. The
clusters selected for this program already have extensive
spectroscopic observations and NIR imaging is either in hand or
underway from approved ground based programs. To date, the lower part
of this redshift range has only been marginally studied with HST. Our
sample includes the two most distant, spectroscopically confirmed
superclusters and will significantly increase the baseline over which
evolutionary effects can be studied. The data will also be used to
identify very high-z galaxies via their unique spectral properties.

FGS 9882

The Distance and Mass of the Neutrino-Luminous White Dwarf PG 0122+200

PG 0122+200 is a pulsating hot white dwarf that is believed to radiate
more energy as neutrinos than it does as photons. We propose to
measure with FGS the trigonometric parallax of PG 0122+200 and thereby
determine its distance, luminosity, and mass. Ongoing investigations
from the ground will infer the neutrino luminosity through its effect
on the pulsation periods, thus testing standard and non-standard
lepton theory, but the stellar mass must first be known. The pulsation
spectrum of PG 0122+200 admits two alternative seismological
interpretations, each implying a different mass, luminosity, and
distance. Measurement of an accurate distance will resolve the matter
once and for all and precisely determine the stellar mass. This
project represents the first test of lepton physics in dense {log rho
= 6} plasma and is relevant to the many areas of stellar physics in
which neutrino interactions are important, including recent theories
intended to solve the solar-neutrino problem.

NIC/NIC3 9865

The NICMOS Parallel Observing Program

We propose to continue managing the NICMOS pure parallel program.
Based on our experience, we are well prepared to make optimal use of
the parallel opportunities. The improved sensitivity and efficiency of
our observations will substantially increase the number of
line-emitting galaxies detected. As our previous work has
demonstrated, the most frequently detected line is Halpha at
0.7z1.9, which provides an excellent measure of current star
formation rate. We will also detect star-forming and active galaxies
in other redshift ranges using other emission lines. The grism
observations will produce by far the best available Halpha luminosity
functions over the crucial--but poorly observed--redshift range where
galaxies appear to have assembled most of their stellar mass. This key
process of galaxy evolution needs to be studied with IR data; we found
that observations at shorter wavelengths appear to have missed a large
fraction of the star-formation in galaxies, due to dust reddening. We
will also obtain deep F110W and F160W images, to examine the space
densities and morphologies of faint red galaxies. In addition to
carrying out the public parallels, we will make the fully reduced and
calibrated images and spectra available on-line, with some
ground-based data for the deepest parallel fields included.

ACS/WFC 9860

ESSENCE: Measuring the Dark Energy Equation of State

The accelerating universe appears to be dominated by a dark energy
with a significant negative pressure. The ratio of the pressure to
density of this mysterious energy {its equation of state} is an
observable which can differentiate between the proliferating candidate
theories. We propose to estimate the dark energy equation of state by
observing Type Ia supernovae at redshifts near z=0.7 with HST in
concert with the on-going ESSENCE NOAO Survey program that is
discovering and studying supernovae between 0.3z0.8. We show that an
interesting constraint on the equation of state can be made with
supernovae observed at modest redshifts given the current knowledge of
the matter density. We will follow 10 Type Ia supernovae discovered
from the ground and passed to HST without disrupting its schedule. The
full data set will constrain the equation of state to 10% and strictly
limit the range of possible dark energy models. In keeping with the
ESSENCE policy, these observations will available to the community
immediately.

ACS/WFC/WFPC2 9825

An ACS/WFC H-alpha Survey of the Orion Nebula

We propose to survey nearly 500 square arcminutes of the Orion Nebula
in H-alpha using the ACS/WFC, increasing the sky coverage by an order
of magnitude over the sum of all previous HST observations. This
survey will, for the first time, sample the majority of young stars
and circumstellar environments in the extended Trapezium cluster of 2,
000 low-mass stars. Our primary goal is to determine the survival rate
and statistical properties of protoplanetary disks in the type of
radiation field and dynamical environment in which most stars are
born. The survey will be used to search for new silhouette disks,
bright proplyds, microjets, large-scale outflows, and to characterize
the properties of these objects as a function of location in the
nebula. We will determine accurate proper motions in regions where
previous HST data exist. However, 90% of our fields will be observed
with HST for the first time. This survey will provide the first
complete census of pre-main sequence objects and outflows in an HII
region and will constrain the extent of hazards to planet formation in
such environments. The images will also provide a legacy for future
stellar and nebular variability studies and proper motion measurements
by providing a first epoch data base.

STIS 9786

The Next Generation Spectral Library

We propose to continue the Cycle 10 snapshot program to produce a Next
Generation Spectral Library of 600 stars for use in modeling the
integrated light of galaxies and clusters. This program is using the
low dispersion UV and optical gratings of STIS. The library will be
roughly equally divided among four metallicities, very low {[Fe/H] lt
-1.5}, low {[Fe/H] -1.5 to -0.5}, near-solar {[Fe/H] -0.3 to 0.1}, and
super-solar {[Fe/H] gt 0.2}, well-sampling the entire HR-diagram in
each bin. Such a library will surpass all extant compilations and have
lasting archival value, well into the Next Generation Space Telescope
era. Because of the universal utility and community-broad nature of
this venture, we waive the entire proprietary period.

STIS 9783

The Ages of Nuclear Star Clusters in Early-type Spiral Galaxies

We propose to obtain STIS G430L spectra of the previously identified
nuclear star cluster in a sample of 16 spiral galaxies of early to
intermediate Hubble type. HST's spatial resolution is required to
separate the nuclear cluster from the underlying galaxy bulge.
Analysis of the spectra with population synthesis methods will reveal
the cluster ages. We will use the age distribution to constrain the
duty cycle of nuclear cluster formation. Comparison of the results to
those for a larger sample of nuclear clusters in late-type, bulgeless
galaxies will allow us to investigate possible differences between the
formation mechanisms of nuclear clusters in early and late Hubble
types. Such differences might be expected because galaxy bulges show a
dichotomy: in late Hubble types, the surface brightness profiles are
best described by an exponential, while they follow a de Vaucouleurs
law in earlier types. Although the reason for this dichotomy is still
unknown, it is plausible that galaxy bulges have different formation
mechanisms at the two ends of the Hubble sequence. We know that {1}
nuclear cluster formation is linked to the funneling of gas towards
the nucleus via gravitational torques from stellar bars, {2} a nuclear
mass concentration can make bars unstable, and {3} unstable bars can
form bulges. Therefore, the age distribution of nuclear star clusters
contains important clues to the evolution of galaxy centers and
promises new insight into the origin of the Hubble sequence.

ACS/WFC/HRC 9771

The local Hubble flow and the density field within 6 Mpc

Great progress has been made recently in accurate distance
measurements of nearby galaxies beyond the Local Group based on the
luminosity of the tip of the red giant branch {TRGB}. Over the last
three years, snapshot surveys with HST have provided us with the TRGB
distances for more than a hundred nearby galaxies obtained with an
accuracy of about 10%. The local velocity field within 5 Mpc exhibits
a significant anisotropy which disagrees with a spherical
Virgo-centric flow. The local Hubble flow is very cold, with 1-D rms
deviations of ~30 km/s. Cosmological simulations with Cold Dark Matter
can only realize such low dispersions with a combination of a low mean
density of matter and a substantial component with negative pressure.
There may be a constraint on the equation of state w=-p/rho. Our
observations will concentrate on 116 galaxies whose expected distances
lie within 4 - 6 Mpc, allowing us to trace a Dark Matter distribution
in the Local Volume with twice the information currently available.
The program is a good one for SNAP mode because the order and rate
that the observations are made are not very important, as long as
there is good completion over several years.

STIS/CCD/MA1 9759

Confirmation of New Candidates for the Study of Intergalactic Helium

The reionization of intergalactic helium is believed to take place
between redshift 3 and 4. The study of HeII Lyman-alpha absorption in
four quasars at 2.7z3.3 demonstrates the great potential of such an
intergalactic-medium {IGM} probe and suggests that the reionization
epoch is at higher redshifts. Clean quasar sightlines may be found
only from massive pre-selection processes in the optical and UV,
because of random, severe bsorption by intervening Lyman-limit
systems. The SDSS has discovered approximately 36000 quasars, and we
propose to verify the UV detectability in 70 top candidates for helium
studies extending to even higher redshift. Our proposed approach has
already proven successful, and additional positive confirmations will
allow follow-up observations, with STIS or COS, to pinpoint the epoch
of reionization of the IGM, and the evolution of its properties near
that period.

ACS/HRC 9747

An Imaging Survey of the Statistical Frequency of Binaries Among
Exceptionally-Young Dynamical Families in the Main Asteroid Belt

We propose an ambitious SNAPSHOT program to determine the frequency of
binaries among two very young asteroid families in the Main Belt, with
potentially profound implications. These families {of C- and S-type}
have recently been discovered {Nesvorny et al. 2002, Nature 417, 720},
through dynamical modeling, to have been formed at 5.8 MY and 8.3 MY
ago in catastrophic impact events. This is the first time such
precise and young ages have been assigned to a family. Main-belt
binaries are almost certainly produced by collisions, and we would
expect a young family to have a significantly higher frequency of
binaries than the background, because they may not yet have been
destroyed by impact or longer-term gravitational instabilities. In
fact, one of the prime observables from such an event should be the
propensity for satellites. This is the best way that new numerical
models for binary production by collisions {motivated largely by our
ground-based discoveries of satellites among larger asteroids}, can be
validated and calibrated. HST is the only facility that can be used to
search for binaries among such faint objects {V17.5}. We will also
measure two control clusters, one being an "old" family, and the other
a collection of background asteroids that do not have a family
association, and further compare with our determined value for the
frequency of large main-belt binaries {2%}. We request visits to 180
targets, using ACS/HRC.

ACS/WFC 9744

HST Imaging of Gravitational Lenses

Gravitational lenses offer unique opportunities to study cosmology,
dark matter, galactic structure, galaxy evolution and quasar host
galaxies. They are also the only sample of galaxies selected based on
their mass rather than their luminosity or surface brightness. While
gravitational lenses can be discovered with ground-based optical and
radio observations, converting them into astrophysical tools requires
HST. HST has demonstrated that it is the only telescope that can in
each case precisely locate the lens galaxy, measure its luminosity,
color and structure, and search for lensed images of the source host
galaxy given the typical image separations of ~1''. We will obtain
ACS/WFC V and I images and NICMOS H images of 21 new lenses never
observed by HST and NICMOS H images of 16 lenses never observed by HST
in the IR. As in previous cycles, we request that the data be made
public immediately.

NIC2 9726

A NICMOS search for obscured supernovae in starburst galaxies

Recent near-IR monitoring campaigns were successful in detecting
obscured supernovae {SNe} in starburst galaxies. The inferred SN rate
is much higher than that obtained in previous optical campaigns, but
it is still significantly lower than expected by the high level star
formation of these systems. One possible explanation for the shortage
of SNe is that most of them occur in the nuclear region, where the
limited angular resolution of groundbased observations prevents their
detection. We propose NICMOS SNAP observations of a sample of
starburst galaxies already observed once by NICMOS, with the goal of
exploiting its sensitivity and angular resolution to detect nuclear
obscured SNe which might have been missed by groundbased surveys.
These observation will allow to assess the real SN rate in starbust
galaxies and deliver a sample of SN occurring in the extreme
environment of galactic nuclei. We expect to detect more than 55 SNe
{if the whole sample is observed}. If the number of SNe detected in
the program is much lower than expected it would prompt for a revision
of our understanding of the relation between the star formation rate
and the SN rate.

WFPC2 9709

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.

STIS 9633

STIS parallel archive proposal - Nearby Galaxies - Imaging and
Spectroscopy

Using parallel opportunities with STIS which were not allocated by the
TAC, we propose to obtain deep STIS imagery with both the Clear
{50CCD} and Long-Pass {F28X50LP} filters in order to make
color-magnitude diagrams and luminosity functions for nearby galaxies.
For local group galaxies, we also include G750L slitless spectroscopy
to search for e.g., Carbon stars, late M giants and S-type stars. This
survey will be useful to study the star formation histories, chemical
evolution, and distances to these galaxies. These data will be placed
immediately into the Hubble Data Archive.

ACS/STIS 9451

ACS Imaging and STIS Spectroscopy of Binary Brown Dwarfs

We have compiled a sample of 9 spatially resolved binary brown dwarfs
{18 objects}, and now propose ACS imaging and STIS spectroscopic
follow-up observations. While theoretical models on the interplay of
chemical and physical processes governing brown dwarf atmospheres have
reached a high level of sophistication, interpretation of
observational data remains difficult. As brown dwarfs never stabilize
themselves on the hydrogen main sequence, there is always an ambiguity
between the temperature or luminosity of any brown dwarf and its mass
or age. The individual components of brown dwarf binaries, however,
are expected to be coeval and have the same underlying chemical
composition. This provides crucial constraints on any model, thus
greatly reducing the number of the free parameters. The aim is to
obtain photometric and spectroscopic data to probe the physical and
chemical properties of the brown dwarf atmospheres, as well as second
epoch astrometric data to characterize th e orbital motion. The study
will provide important feedback on theoretical model atmospheres and
evolutionary tracks for brown dwarfs. As such, it will be an important
step towards a better understanding of objects with spectral
properties intermediate between those of giant planets and late-type
stars.

NICMOS 8791

NICMOS Post-SAA calibration - CR Persistence Part 2

A new procedure proposed to alleviate the CR-persistence problem of
NICMOS. Dark frames will be obtained immediately upon exiting the SAA
contour 23, and every time a NICMOS exposure is scheduled within 50
minutes of coming out of the SAA. The darks will be obtained in
parallel in all three NICMOS Cameras. The POST-SAA darks will be
non-standard reference files available to users with a USEAFTER
date/time mark. The keyword 'USEAFTER=date/time' will also be added to
the header of each POST-SAA DARK frame. The keyword must be populated
with the time, in addition to the date, because HST crosses the SAA ~8
times per day so each POST-SAA DARK will need to have the appropriate
time specified, for users to identify the ones they need. Both the raw
and processed images will be archived as POST-SAA DARKSs. Generally we
expect that all NICMOS science/calibration observations started within
50 minutes of leaving an SAA will need such maps to remove the CR
persistence from the science images. Each observation will need its
own CRMAP, as different SAA passages leave different imprints on the
NICMOS detectors.

STIS/CCD 10085

STIS Pure Parallel Imaging Program: Cycle 12

This is the default archival pure parallel program for STIS during
cycle 12.

STIS/MA1 10083

HST UV Images of Saturn's Aurora Coordinated with Cassini Solar Wind
Measurements

A key measurement goal of the Cassini mission to Saturn is to obtain
simultaneous solar wind and auroral imaging measurements in a campaign
scheduled for Jan. 2004. Cassini will measure the solar wind
approaching Saturn continuously from 9 Jan. - 6 Feb., but not closer
to Saturn due to competing spacecraft orientation constraints. The
only system capable of imaging Saturn's aurora in early 2004 will be
HST. In this community DD proposal we request the minimum HST time
needed to support the Cassini mission during the solar wind campaign
with UV images of Saturn's aurora. Saturn's magnetosphere is
intermediate between the "closed" Jovian case with large internal
sources of plasma and the Earth's magnetosphere which is open to solar
wind interactions. Saturn's aurora has been shown to exhibit large
temporal variations in brightness and morphology from Voyager and HST
observations. Changes of auroral emitted power exceeding one order of
magnitude, dawn brightenings, and latitudinal motions of the main oval
have all been observed. Lacking knowledge of solar wind conditions
near Saturn, it has not been possible to determine its role in
Saturn's auroral processes, nor the mechanisms controlling the auroral
precipitation. During Cassini's upcoming approach to Saturn there will
be a unique opportunity to answer these questions. We propose to image
one complete rotation of Saturn to determine the corotational and
longitudinal dependences of the auroral activity. We will then image
the active sector of Saturn once every two days for a total coverage
of 26 days during the Cassini campaign to measure the upstream solar
wind parameters. This is the minimum coverage needed to ensure
observations of the aurora under solar wind pressure variations of
more than a factor of two, based on the solar wind pressure variations
measured by Voyager 2 near Saturn on the declining phase of solar
activity. The team of proposers has carried out a similar coordinated
observing campaign of Jupiter during the Cassini flyby, resulting in a
set of papers and HST images on the cover of Nature on 28 February
2002.

WFPC2 10082

POMS Test Proposal: WFII backup parallel archive proposal

This is a POMS test proposal designed to simulate scientific plans

WFPC2 10076

WFPC2 Cycle 12 CTE Monitor

Monitor CTE changes during Cycle 12, including 2X2 binning
characterization.

WFPC2 10069

WFPC2 CYCLE 12 Supplemental Darks, Part 1/3

This dark calibration program obtains 3 dark frames every day to
provide data for monitoring and characterizing the evolution of hot
pixels.

ACS/HRC/WFC 10059

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.

STIS/CCD 10019

CCD Bias Monitor - Part 1

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.

STIS/CCD 10017

CCD Dark Monitor-Part 1

Monitor the darks for the STIS CCD.

NIC3 10014

Spectrophotometry of FAINT IR STANDARDS

Faint spectrophotometric standard stars required for COS and the SBC
channel on ACS have been established via the STIS FASTEX program that
has executed over the last three cycles. Cycle 12 is an especially
opportune time to establish companion faint IR standards for WFC3,
because the NICMOS proposal 9998 includes observations in cycle 12 of
all 6 of the primary standard stars in order to establish the absolute
flux calibration of the three grism modes to 1%. In addition to WFC3,
these new faint secondary IR standards will be a significant step
towards establishing flux standards for JWST, as well as for SNAP,
SIRTF, and SOFIA. The 6 primary standards included in Propid=9998 are
in the range of V=11-13 and include three hot pure hydrogen WDs and 3
solar analogs. We propose to establish new IR faint standards in the
15-17 mag range. Appropriate spectral types for faint IR standards are
solar analogs and hotter WDs. Many M type and cooler stars are
variable, so that long term monitoring is required before committing
HST time to such cool stars. A few G type and WD faint stars will
provide a set of faint IR standards with minimal sky and color
coverage. Existing HST images of any candidates can provide
verification that there are no contaminating stars above the 1% level
within 2-3arcsec. However, the ACS calibration field in 47 Tuc is too
crowded for linking to ground based observations. If the other
candidates are selected from SDSS or other ground based data, then the
NICMOS and STIS acquisition images can provide this verification, as
well as correction factors for arbitrary photometric size apertures.
The SNAP team is providing the northern faint stars using unreleased
SDSS data. In addition, the extreme coolest types such as L and T
stars have proven essential to sorting out the long wavelength QE of
ACS; both the ACS and eventually WFC3 calibrations could be improved
with knowledge of L and T SEDs in the region beyond 0.95 microns. In
addition to the primary purpose of ACS QE vs. wavelength and broad
band F814W and F850LP calibrations, these three stars in C.} below are
at the flux level required for WFC3 grism calibration. The brighter M,
L, and T standard stars will each require a NICMOS orbit, while each
faint standard requires two Nicmos orbits and one STIS orbit for
complete wavelength coverage. The STIS spectra of the M and L stars
are done as ACS calibrations in cycles 12 and 11, respectively. An
additional faint WD has already been proposed for 2 Nicmos and 4 STIS
orbits in their cycle 12 programs already. See Table 1 for a summary
of the 18 orbit allocation for this program 10014. Bright stars in the
V=0-6 mag range would be useful for direct comparisons to NIST
calibrated lamps. This comparison would offer the opportunity to
compare two fundamentally different realms of physics: pure hydrogen
stellar models and laboratory black body physics. Unfortunately, the
Nicmos bright limit is V=~8 for a solar analog and a 1s exposure
without defocussing the OTA. The primary Sloan standard BD+17d4708 at
V=9.9 is safely fainter than this Nicmos limit.

WFPC2/ACS/HRC/WFC 10013

Focus Monitor

The focus of HST is measured from WFPC2/PC and ACS/HRC images of
stars. Multiple exposures are taken in parallel over an orbit to
determine the influence of breathing on the derived mean focus.
Observations are taken of clusters with suitable orientations to
ensure stars appear in all fields.

FLIGHT OPERATIONS SUMMARY:

Significant Spacecraft Anomalies: (The following are preliminary reports of
potential non-nominal performance that will be investigated.)

HSTAR 9274: GS Re-acquisition (2,3,2) @ 009/20:23:56Z (during LOS)
resulted in FL backup FGS2 due to SSLEX on FGS 3. Following FHST Map
scheduled for the time 009/21:22Z showed attitude error of 1.104,
0.632, and 1.595 arcsec. Following GS re-acquisition @ 009/22:03:43Z
passed with FL. Under investigation.

HSTAR 9275: GS Acquisition (1,2,2) @ 010/04:13:51Z resulted in FL
backup FGS 1 due to SSLE on FGS 2. Prior FM Updates @ 010/03:56Z and
03:59Z showed good attitude error vector. Under investigation.

HSTAR 9276: GS Acquisition (1,2,2) @ 010/15:24:57Z resulted in FL
backup using FGS 1 due to SSLE on FGS 2. Under investigation.

HSTAR 9277: FHST FM Update and GS Acquisition Failure @ 011/20:25:43Z
and 20:28:28Z failed with Error Box results showing "3 FAILED" for
mnemonics QEBSTFG0, QEBSTFG1, and QEBSTFG2. GS Acquisition (1,3,1)
failed due to radius limit exceeded on FGS 1. Under investigation.

HSTAR 9278: FHST Roll Delay Update failure @ 011/21:59:10Z. Error
Box results QEBSTF0, QEBSTFG1, and QEBSTFG2 showed "3 FAILED". Under
investigation.

COMPLETED OPS REQs: NONE

OPS NOTES EXECUTED: NONE

SCHEDULED SUCCESSFUL FAILURE TIMES
FGS GSacq 28 27 See HSTAR # 9277
FGS REacq 17 17
FHST Update 72 69 See HSTAR #
9277 & 9278
LOSS of LOCK


SIGNIFICANT EVENTS: None


 




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