Daily 3732

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 3732

PERIOD COVERED: DOYs 310-312

OBSERVATIONS SCHEDULED

ACS/HRC 9792

Uncovering the CV population in M15: a deep, time-resolved, far-UV
survey of the cluster core

We propose to carry out a deep, far-ultraviolet {FUV}, time-resolved
for faint cataclysmic variables {CVs} and other dynamically-formed
objects in the globular cluster {GC} M15. We will use the ACS/SBC to
carry out 6 epochs of FUV imaging of this cluster in a single filter,
and will use two additional visits to obtain images in other FUV and
NUV filters. Since crowding is not a problem in the FUV, this will
yield time-resolved FUV photometry of all blue objects in the cluster
core. Our CV census will be both deep enough to be essentially
complete and ``broad'' enough to involve all of the following CV
characteristics: {1} UV brightness; {2} blue FUV spectral shape; {3}
strong CIV and HeII emission; {4} short time-scale {$sim$ minutes}
variability {flickering, WD spin}; {6} intermediate time-scale {$sim$
hours} variability {orbital variations}; {7} long time-scale {$sim$
weeks} variability {dwarf nova eruptions}. We will thus find the CV
population in M15, if it exists. In addition, our survey will detect
numerous blue stragglers and hot white dwarfs, as well as any other
blue objects near the core. Finally, our photometry will yield
high-quality FUV light curves of the two low-mass x-ray binaries in
M15.

NIC1/NIC2/NIC3 8794

NICMOS Post-SAA calibration - CR Persistence Part 5

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.

ACS/HRC 10398

Transcending Voyager: A Deeper Look at Neptune's Ring-Moon System

We will use the High Resolution Channel {HRC} of ACS to study the
inner rings, arcs and moons of Neptune with a sensitivity that exceeds
that achieved by Voyager 2 during its 1989 flyby. Our study will
reveal any moons down to V magnitude 25.5, to address a peculiar
truncation in the size distribution of inner moons and to look for the
"shepherds" and source bodies for Neptune's dusty rings. {For
comparison, Neptune's smallest known moon is Naiad, at magnitude
23.9}. Recent ground-based studies show that the mysterious arcs in
the Adams Ring continue to shift and change, and may be fading away
entirely. We will obtain the visual-band data uniquely necessary to
determine whether the arcs are fading. Long-term monitoring of the
arcs at high resolution and sensitivity will reveal their gradual
changes more clearly and enable us to assess the role of Galatea,
whose resonances are widely believed to confine the arcs.

ACS/WFC 10393

Hubble Heritage Observations of Eagle Nebula

Observe Eagle Nebula with 5 filters.

ACS/HRC/WFC 10370

CCD Hot Pixel Annealing

Hot pixel annealing will continue to be performed once every 4 weeks.
The CCD TECs will be turned off and heaters will be activated to bring
the detector temperatures to about +20C. This state will be held for
approximately 12 hours, after which the heaters are turned off, the
TECs turned on, and the CCDs returned to normal operating condition.
To assess the effectiveness of the annealing, a bias and four dark
images will be taken before and after the annealing procedure for both
WFC and HRC. The HRC darks are taken in parallel with the WFC darks.
The charge transfer efficiency {CTE} of the ACS CCD detectors declines
as damage due to on-orbit radiation exposure accumulates. This
degradation has been closely monitored at regular intervals, because
it is likely to determine the useful lifetime of the CCDs. We will now
combine the annealing activity with the charge transfer efficiency
monitoring and also merge into the routine dark image collection. To
this end, the CTE monitoring exposures have been moved into this
proposal . All the data for this program is acquired using internal
targets {lamps} only, so all of the exposures should be taken during
Earth occultation time {but not during SAA passages}. This program
emulates the ACS pre-flight ground calibration and post-launch SMOV
testing {program 8948}, so that results from each epoch can be
directly compared. Extended Pixel Edge Response {EPER} and First Pixel
Response {FPR} data will be obtained over a range of signal levels for
both the Wide Field Channel {WFC}, and the High Resolution Channel
{HRC}.

ACS/HRC/WFC 10367

ACS CCDs daily monitor- cycle 13 - part 1

This program consists of a set of basic tests to monitor, the read
noise, the development of hot pixels and test for any source of noise
in ACS CCD detectors. The files, biases and dark will be used to
create reference files for science calibration. This programme will be
for the entire lifetime of ACS.

WFPC2 10363

WFPC2 CYCLE 13 Intflat and Visflat Sweeps and Filter Rotation Anomaly
Monitor

Using intflat observations, this WFPC2 proposal is designed to monitor
the pixel-to-pixel flatfield response and provide a linearity check.
The intflat sequences, to be done once during the year, are similar to
those from the Cycle 12 program 10075. The images will provide a
backup database in the event of complete failure of the visflat lamp
as well as allow monitoring of the gain ratios. The sweep is a
complete set of internal flats, cycling through both shutter blades
and both gains. The linearity test consists of a series of intflats in
F555W, in each gain and each shutter. As in Cycle 12, we plan to
continue to take extra visflat, intflat, and earthflat exposures to
test the repeatability of filter wheel motions.

ACS/WFC/NIC/NIC3/WFPC2 10246

The HST survey of the Orion Nebula Cluster

We propose a Treasury Program of 104 HST orbits to perform the
definitive study of the Orion Nebula Cluster, the Rosetta stone of
star formation. We will cover with unprecedented sensitivity {23-25
mag}, dynamic range {~12 mag}, spatial resolution {50mas}, and
simultaneous spectral coverage {5 bands} a ~450 square arcmin field
centered on the Trapezium stars. This represents a tremendous gain
over the shallow WFC1 study made in 1991 with the aberrated HST on an
area ~15 times smaller. We maximize the HST observing efficiency using
ACS/WFC and WFPC2 in parallel with two opposite roll angles, to cover
the same total field. We will assemble the richest, most accurate and
unbiased HR diagram for pre-main-sequence objects ever made. Combined
with the optical spectroscopy already available for ~1000 sources and
new deep near-IR imaging and spectroscopy {that we propose as Joint
HST-NOAO observations}, we will be able to attack and possibly solve
the most compelling questions on stellar evolution: the calibration of
pre-main-sequence evolutionary tracks, mass segration and the
variation of the initial mass function in different environments, the
evolution of mass accretion rates vs. age and environment, disk
dissipation in environments dominated by hard vs. soft-UV radiation,
stellar multiplicity vs. disk fraction. In addition, we expect to
discover and classify an unknown, but substantial, population of
pre-Main Sequence binaries, low mass stars and brown dwarfs down to
~10 MJup. This is also the best possible way to discover dark
silhouette disks in the outskirts of the Orion Nebula and study their
evolutionary status through multicolor imaging. This program is timely
and extremely well leveraged to other programs targeting Orion: the
ACS H-alpha survey of the Orion Nebula, the recently completed 850ks
ultradeep Chandra survey, the large GTO programs to be performed with
SIRTF, plus the availability of 2MASS and various deep JHK surveys of
the core recently done with 8m class telescopes.

NIC/NIC3 10226

The NICMOS Grism Parallel Survey

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 10216

Co-evolution of spheroids and black holes

The masses of the giant black holes in galaxies are correlated with
the luminosities, masses, and velocity dispersions of their host
spheroids. This empirical connection of phenomena on widely different
scales {from sub-parsec to kiloparsec} suggests that the evolution of
a galaxy and its central black hole are closely linked. We propose to
test various unified formation models, by measuring the cosmic
evolution of the black hole/spheroid relations, back to z=0.37 {a
lookback time of 4 Gyrs}. We will obtain 1-orbit ACS images of a
sample of 20 Seyfert 1 galaxies, for which we already have extensive
new ground-based measures of the black hole masses and the stellar
velocity dispersions. HST resolution is required for accurate
measurement of the nonstellar AGN continuum, and the luminosity and
effective radius of the bulge of each host galaxy. This will complete
the set of observables needed to map the co-evolution of spheroids and
black-holes. The proposed sample is the minimum required to make the
first measure of the black hole mass/bulge correlation and of the
fundamental plane for active galaxies outside the local Universe.

FGS 10202

Resolving OB Binaries in the Carina Nebula, Resuming the Survey

In March 2002 we carried out a small, high-angular resolution survey
of some of the brightest OB stars in the Carina Nebula with FGS1r in
an attempt to resolve binary systems which had thus far evaded
detection by other techniques. Of 23 stars observed, 5 new OB binaries
were discovered with component separations ranging from 0.015"
to0.325". This yield over the spatial domain of FGS1r's angular
resolution, coupled with published statistics of the incidence of OB
stars in short-period spectroscopic, and long-period visual binaries
suggests that the fraction of binarity or multiplicity among OB stars
is near unity. Our unexpected resolution of the prototype O2 If* star
HD 93129A as a 55 milli-arcsecond double is a case in point that great
care must be exercised when one attempts to establish the IMF and
upper-mass cuttoff at the high-mass end of the HR diagram. We propose
to resume the survey to observe a larger, statistically meaningful
sample of OB stars to establish a firm assessment of multiplicity at
the high-mass end of the IMF in these clusters. We will also
investigate the single-star/binary-star status of several
astrophysically important, individual stars in order to enable a
better understanding of the evolution of high-mass stars.

ACS/HRC/NIC1/WFC 10190

The Star Formation History and Metallicity Evolution of M33: A
Comprehensive Study of Disk Evolution

We will obtain deep, panchromatic imaging photometry of stellar
populations in four fields ranging from 0.5 to 4 scale lengths across
the disk of the Local Group spiral M33. The observations are designed
to detect the oldest main-sequence turnoffs in three outer disk
fields, and to reach the crowding limit in the innermost field. We
will combine the photometry data with information we already have
in-hand on abundances from stars and H II regions in M33 to derive the
star formation history and metallicity evolution of the M33 disk. The
information from our four fields will allow us to obtain {1} the ages
of the oldest disk stars and the radial variation of their ages; {2}
the radial variation of the star formation history and its nature
{e.g., constant, declining, or bursting}; and {3} the metallicity
distribution in each field and the time evolution of the metallicity
gradient. Our team, an experienced mix of photometrists,
spectroscopists, and galaxy evolution theorists, will use the results
from this program to construct a comprehensive chemo-dynamical model
for the M33 disk. This detailed study of M33 will be a key in
developing an understanding of the formation and evolution of disks
that can be applied to studies of disks at both low and high redshift,
and will also yield a wealth of information on stellar populations,
chemical evolution, and star clusters that will be of great value to
future investigators.

ACS/WFC/NIC2 10189

PANS-Probing Acceleration Now with Supernovae

Type Ia supernovae {SNe Ia} provide the most direct evidence for an
accelerating Universe, a result widely attributed to dark energy.
Using HST in Cycle 11 we extended the Hubble diagram with 6 of the 7
highest-redshift SNe Ia known, all at z1.25, providing conclusive
evidence of an earlier epoch of cosmic deceleration. The full sample
of 16 new SNe Ia match the cosmic concordance model and are
inconsistent with a simple model of evolution or dust as alternatives
to dark energy. Understanding dark energy may be the biggest current
challenge to cosmology and particle physics. To understand the nature
of dark energy, we seek to measure its two most fundamental
properties: its evolution {i.e., dw/dz}, and its recent equation of
state {i.e., w{z=0}}. SNe Ia at z1, beyond the reach of the ground
but squarely within the reach of HST with ACS, are crucial to break
the degeneracy in the measurements of these two basic aspects of dark
energy. The SNe Ia we have discovered and measured with HST in Cycle
11, now double the precision of our knowledge of both properties. Here
we propose to quadruple the sample of SNe Ia at z1 in the next two
cycles, complementing on-going surveys from the ground at z1, and
again doubling the precision of dark energy constraints. Should the
current best fit model prove to be the correct one, the precision
expected from the current proposal will suffice to rule out a
cosmological constant at the 99% confidence level. Whatever the
result, these objects will provide the basis with which to extend our
empirical knowledge of this newly discovered and dominant component of
the Universe, and will remain one of the most significant legacies of
HST. In addition, our survey and follow-up data will greatly enhance
the value of the archival data within the target Treasury fields for
galaxy studies.

ACS/HRC 10185

When does Bipolarity Impose itself on the Extreme Mass Outflows from
AGB Stars? An ACS SNAPshot Survey

Essentially all well-characterized preplanetary nebulae {PPNe} --
objects in transition between the AGB and planetary nebula
evolutionary phases - are bipolar, whereas the mass-loss envelopes of
AGB stars are strikingly spherical. In order to understand the
processes leading to bipolar mass-ejection, we need to know at what
stage of stellar evolution does bipolarity in the mass-loss first
manifest itself? Our previous SNAPshot surveys of a PPNe sample {with
ACS & NICMOS} show that roughly half our targets observed are
resolved, with well-defined bipolar or multipolar morphologies.
Spectroscopic surveys of our sample confirm that these objects have
not yet evolved into planetary nebulae. Thus, the transformation from
spherical to aspherical geometries has already fully developed by the
time these dying stars have become preplanetary nebulae. From this
new and surprising result, we hypothesize that the transformation to
bipolarity begins during the very late AGB phase, and happens very
quickly, just before, or as the stars are evolving off the AGB. We
propose to test this hypothesis quantitatively, through a SNAPshot
imaging survey of very evolved AGB stars which we believe are nascent
preplanetary nebulae; with our target list being drawn from published
lists of AGB stars with detected heavy mass-loss {from millimeter-wave
observations}. This survey is crucial for determining how and when the
bipolar geometry asserts itself. Supporting kinematic observations
using long-slit optical spectroscopy {with the Keck}, millimeter and
radio interferometric observations {with OVRO, VLA & VLBA} are being
undertaken. The results from this survey {together with our previous
work} will allow us to draw general conclusions about the onset of
bipolar mass-ejection during late stellar evolution, and will provide
crucial input for theories of post-AGB stellar evolution. Our survey
will produce an archival legacy of long-standing value for future
studies of dying stars.

ACS/WFC 10174

Dark-matter halos and evolution of high-z early-type galaxies

Gravitational lensing and stellar dynamics provide two complementary
methods to determine the mass distribution and evolution of luminous
and dark-matter in early-type {E/S0} galaxies. The combined study of
stellar dynamics and gravitational lensing allows one to break
degeneracies inherent to each method separately, providing a clean
probe of the internal structure of massive galaxies. Since most lens
galaxies are at redshifts z=0.1-1.0, they also provide the required
look-back time to study their structural and stellar-population
evolution. We recently analyzed 5 E/S0 lens galaxies between z=0.5 and
1.0, combining exquisite Hubble Space Telescope imaging data with
kinematic data from ground-based Keck spectroscopy, placing the first
precise constraints on the dark-matter mass fraction and its inner
slope beyond the local Universe. To expand the sample to ~30 systems
-- required to study potential trends and evolution in the E/S0 mass
profiles -- we propose to target the 49 E/S0 lens-galaxy candidates
discovered by Bolton et al. {2004} from the Sloan Digital Sky Survey
{SDSS}. With the average lens rate being 40% and some systems having a
lensing probability close to unity, we expect to discover ~20 strong
gravitational lenses from the sample. This will triple the current
sample of 9 E/S0 systems, with data in hand. With the sample of 30
systems, we will be able to determine the average slope of the
dark-matter and total mass profile of E/S0 galaxies to 10% and 4%
accuracy, respectively. If present, we can simultaneously detect 10%
evolution in the total mass slope with 95% confidence. This will
provide unprecedented constraints on E/S0 galaxies beyond the local
Universe and allow a stringent test of their formation scenarios and
the standard cosmological model.

NIC2 10173

Infrared Snapshots of 3CR Radio Galaxies

Radio galaxies are an important class of extragalactic objects: they
are one of the most energetic astrophysical phenomena and they provide
an exceptional probe of the evolving Universe, lying typically in high
density regions but well-represented across a wide redshift range. In
earlier Cycles we carried out extensive HST observations of the 3CR
sources in order to acquire a complete and quantitative inventory of
the structure, contents and evolution of these important objects.
Amongst the results, we discovered new optical jets, dust lanes,
face-on disks with optical jets, and revealed point-like nuclei whose
properties support FR-I/BL Lac unified schemes. Here, we propose to
obtain NICMOS infrared images of 3CR sources with z0.3 as a major
enhancement to an already superb dataset. We aim to deshroud dusty
galaxies, study the underlying host galaxy free from the distorting
effects of dust, locate hidden regions of star formation and establish
the physical characteristics of the dust itself. We will measure
frequency and spectral energy distributions of point-like nuclei,
expected to be stronger and more prevalent in the IR, seek spectral
turnovers in known synchrotron jets and find new jets. We will
strongly test unified AGN schemes and merge these data with existing
X-ray to radio observations. The resulting database will be an
incredibly valuable resource to the astronomical community for years
to come.

WFPC2 10170

Atmospheric Variability on Uranus and Neptune

We propose Snapshot observations of Uranus and Neptune to monitor
changes in their atmospheres on time scales of weeks, months, and
years. Uranus is rapidly approaching equinox in 2007, with another 4
degrees of latitude becoming visible every year. Recent HST
observations during this epoch {including 6818: Hammel, Lockwood, and
Rages; 7885: Hammel, Karkoschka, and Marley; 8680: Hammel, Rages,
Lockwood, and Marley; and 8634: Rages, Hammel, Lockwood, Marley, and
McKay} have revealed strongly wavelength-dependent latitudinal
structure and the presence of numerous visible-wavelength cloud
features in the northern hemisphere. Long-term ground-based
observations {Lockwood and Thompson 1999} show seasonal brightness
changes whose origins are not well understood. Recent near-IR images
of Neptune obtained using adaptive optics on the Keck Telescope
together with images from our Cycle 9 Snapshot program {8634} show a
general increase in activity at south temperate latitudes as well as
the possible development of another Great Dark Spot. Further Snapshot
observations of these two dynamic planets will elucidate the nature of
long-term changes in their zonal atmospheric bands and clarify the
processes of formation, evolution, and dissipation of discrete albedo
features.

NIC2 10169

Star Formation in Luminous Infrared Galaxies: giant HII Regions and
Super Star Clusters

Luminous Infrared Galaxies {LIRGs, LIR = 10^11-10^12Lsol} and
Ultraluminous Infrared Galaxies {LIR10^12Lsol} account for
approximately 75% of all the galaxies detected in the mid-infrared in
the redshift range z=0-1.5. In the local universe it is found that
LIRGs are predominantly powered by intense star formation {SF}.
However, the physical conditions and processes governing such dramatic
activity over scales of tens to a few hundred parsecs are poorly
known. In the last decade HST has been playing a significant role,
mainly with the discovery of super star clusters {SSCs}, and more
recently, giant HII regions. Based on observations of a few LIRGs, we
found that these giant HII regions and associated SSCs appear to be
more common in LIRGs than in normal galaxies, and may dominate the
star formation activity in LIRGs. A larger sample is required to
address fundamental questions. We propose an HST/NICMOS targeted
campaign of a volume limited sample {v5200km/s} of 24 LIRGs. This
proposal will probe the role of giant HII regions in the overall
energetics of the current star formation, their relation to SSCs, and
the dependence of star formation properties on other parameters of
LIRGs. Such detailed knowledge of the SF properties of LIRGs in the
local universe is essential for understanding galaxies at high
redshift.

ACS/WFC 10152

A Snapshot Survey of a Complete Sample of X-ray Luminous Galaxy
Clusters from Redshift 0.3 to 0.7

We propose a public, uniform imaging survey of a well-studied,
complete, and homogeneous sample of X-ray clusters. The sample of 73
clusters spans the redshift range between 0.3-0.7. The samples spans
almost 2 orders of magnitude of X-ray luminosity, where half of the
sample has X-ray luminosities greater than 10^44 erg/s {0.5-2.0 keV}.
These snapshots will be used to obtain a fair census of the morphology
of cluster galaxies in the cores of clusters, to detect radial and
tangential arc candidates, to detect optical jet candidates, and to
provide an approximate estimate of the shear signal of the clusters
themselves, and potentially an assessment of the contribution of large
scale structure to lensing shear.

ACS/WFC/WFPC2 10129

Resolving Globular Clusters in NGC 1399

We intend to use the ACS/WFC to measure structural parameters {half
light radius, King core radius and concentration parameter} of
individual globular clusters {GCs} in NGC 1399. Very little is known
about structural parameters of globular clusters as a function of
radius outside the Local Group. The proposed observations, arranged in
a 3x3 ACS mosaic, will allow us to perform the first detailed
wide-field study of structural parameters of globular clusters in a
giant elliptical galaxy. In particular we will: 1} study the
size-galactocentric distance relation of globular clusters out to ~55
kpc {~1.6 eff. radius of the GCS} and determine whether the observed
differences in sizes between metal-rich and metal-poor globular
cluster in early-type galaxies are primordial and thereby reflect
fundamental differences in formation, or are due to projection
effects; 2} match the GC position observed with HST/ACS with X-ray
binaries identified over the full Chandra field, and use the above
sizes to constrain physical models for X-ray binary formation in GCs.
3} The wealth of ground-based data available for this system
{photometry+spectroscopy}, will allow us to correlate the structural
properties with other GC properties, such as their chemical
composition, luminosity, etc.

FGS 10113

Trigonometric Calibration of the Period- Luminosity Relations for
Fundamental and First-Overtone Galactic Cepheids

Cepheids are the primary distance indicators for the extragalactic
distance scale and the Hubble constant. The Hubble Constant Key
Project set the zero-point for their Cepheid distance scale by
adopting a distance to the LMC, averaged over a variety of techniques.
However, different methods give an LMC distance modulus ranging from
18.1 to 18.8, and the uncertainty in the Cepheid zero-point is now the
largest contributor to the error budget for H_0. Moreover, the low
metallicity of the LMC raises additional concerns, since the PL
relation probably depends on metallicity. The zero-point can be
determined from Hipparcos parallaxes of Galactic Cepheids out to
several hundred parsecs, but with a typical parallax error of 0.5-1
mas, the Hipparcos error bars are uncomfortably large for this
demanding application. By contrast, HST's FGS1R interferometer can
achieve astrometric accuracy of 0.2 mas. We propose to use FGS1R to
determine trigonometric parallaxes for a sample of 9 nearby Cepheids,
including both fundamental {F} and first-overtone {FO} pulsators. We
show that the improvement in the PL relations for F and FO Cepheids
will be dramatic. We will determine the PL slopes from our nearby
solar- metallicity sample alone, without recourse to nearby galaxies
and the issue of [Fe/H] dependence. The zero-point will be determined
robustly to about 0.05 mag, based on accurate, purely geometrical
measurements.

WFPC2 10112

HST Observations of Astrophysically Important Visual Binaries

This is a continuation of a project begun in Cycle 7 and continued up
through Cycle 11. The program consists of annual or biannual WFPC2 or
FGS observations of three visual binary stars that will ultimately
yield fundamental astrophysical results, once their orbits and masses
are determined. Our targets are the following: {1} Procyon {P = 41
yr}, for which our first WFPC2 images yielded an extremely accurate
angular separation of the bright F star and its much fainter
white-dwarf companion. Combined with ground-based astrometry of the
bright star, our observation significantly revised downward the
derived masses, and brought Procyon A into excellent agreement with
theoretical evolutionary tracks for the first time. With the continued
monitoring proposed here, we will obtain masses to an accuracy of
better than 1%, providing a testbed for theories of both Sun-like
stars and white dwarfs. {2} G 107-70, a close double white dwarf {P =
19 yr} that promises to add two accurate masses to the tiny handful of
white-dwarf masses that are directly known from dynamical
measurements. {3} Mu Cas {P = 21 yr}, a famous metal-deficient G dwarf
for which accurate masses will lead to the stars' helium contents,
with cosmological implications.

FGS 10106

An Astrometric Calibration of the Cepheid Period-Luminosity Relation

We propose to measure the parallaxes of 10 Galactic Cepheid variables.
When these parallaxes {with 1-sigma precisions of 10% or better} are
added to our recent HST FGS parallax determination of delta Cep
{Benedict et al 2002}, we anticipate determining the Period-Luminosity
relation zero point with a 0.03 mag precision. In addition to
permitting the test of assumptions that enter into other Cepheid
distance determination techniques, this calibration will reintroduce
Galactic Cepheids as a fundamental step in the extragalactic distance
scale ladder. A Period-Luminosity relation derived from solar
metallicity Cepheids can be applied directly to extragalactic solar
metallicity Cepheids, removing the need to bridge with the Large
Magellanic Cloud and its associated metallicity complications.

WFPC2 10078

WFPC2 Cycle 12 Close-Out Photometric Cross-Calibration

This proposal is aimed at providing photometric zeropoint
cross-calibration between the commonly used WFPC2 photometric filter
sets and those that will be used for ACS and WFC3. The proposal
consists of observations of a set of standard stars, including the
SDSS primary standard BD+17D4708 {F5} and two red standard stars, VB8
{an M7-dwarf} and 2M0036+18 {L3.5 dwarf}. For the red stars, medium
and broad-band filters redward of F606W are calibrated, while for
BD+17D4708 an extensive set of 22 medium and broad-band filters is
used {from F185W to F1042M}. The intent is to observe these stars with
as many filters as possible, to eventually allow cross-calibration of
archival WFPC2 data with data from ACS, WFC3, SDSS and 2MASS.

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:
1275-0 Adjust ACS Error Count @ 310/17:36z


SCHEDULED SUCCESSFUL FAILURE TIMES
FGS Gsacq 40 40
FGS Reacq 08 08
FHST Update 66 66
LOSS of LOCK

SIGNIFICANT EVENTS: None