Status Report

NASA Hubble Space Telescope Daily Report # 3556

By SpaceRef Editor
February 24, 2004
Filed under , ,

HUBBLE SPACE TELESCOPE – Continuing to collect World Class Science




NIC1/NIC2/NIC3 9995

Photometric Stability

This NICMOS calibration proposal carries out photometric monitoring
observations during Cycle 12. The format of the program is identical
to that of the Cycle 11 program 9639, except that the frequency has
been reduced to bimonthly.

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


Gravitational Microlensing in the NGC 3314A-B Galaxy Pair

Determining the composition of the dark matter that dominates the
masses of galaxies is an important unsolved problem, and the results
of the MACHO Collaboration suggest that some of Milky Way’s dark
matter may be in the form of very old white dwarfs. However, some have
argued that the excess of microlensing events seen by MACHO are due to
a larger than expected microlensing rate for lens stars in the LMC
itself or its tidal debris. We propose to address this question by
detecting microlensing events in the line-of-sight galaxy pair NGC
3314 A & B. The large line-of-sight distance between these galaxies
gives an optical depth that is 3-4 orders of magnitude larger than if
the source stars and lenses were in the same galaxy, and the fact that
the background galaxy is a spiral ensures that there will be a
sufficient number of bright, non-variable source stars. Our proposed
observations should have the sensitivity to detect microlensing by
both ordinary stars and dark matter in NGC 3314A {the foreground
galaxy}. If there are dark matter microlensing events to be found,
they can be clearly distinguished from stellar microlensing events
because they will occur outside the visible disk of NGC 3314A. If
baryonic dark matter is detected in NGC 3314A, we will be able to map
its radial density variation.

ACS/HRC 9976

The Parallaxes and Proper Motions of Two Nearby Neutron Stars

We propose to measure the parallax of two nearby neutron stars to the
highest possible level of accuracy, ~.0.5 mas. The primary goal is to
determine the neutron-star radius at infinity with better than 1 km
precision, and therewith obtain a direct constraint on the equation of
state of matter at supra-nuclear density. The required flux and
temperature determinations are easiest for the so-called isolated or
radio-quiet neutron stars because of their apparently completely
thermal spectrum. We argue that the importance of the possible results
warrants a study to the best possible level of the best possible
sources, and request 24 orbits for the two brightest isolated neutron
stars, RX J1856.5-3754 and RX J0720.4-3125. We will also determine
whether the enigmatic RX J0720.4-3125 is an old magnetar or an
accreting source, based on its luminosity and proper motion.

FGS 9971

FGS Astrometry of a Star Hosting an Extrasolar Planet: The Mass of
Upsilon Andromedae d

We propose observations with HST/FGS to determine the astrometric
elements {perturbation orbit semimajor axis and inclination} produced
by the outermost extra-solar planet orbiting the F8V star Upsilon
Andromedae. These observations will permit us to determine the actual
mass of the planet by providing the presently unknown sin i factor
intrinsic to the radial velocity method which discovered this object.
An inclination, i = 30degrees, within the range of one very low
precision determination using reanalyzed HIPPARCOS intermediate data
products, would produce the observed radial velocity amplitude, K = 66
ms with a companion mass of ~8 M_Jupiter. Such a mass would induce in
Upsilon Andromedae a perturbation semi-major axis, Alpha = 0arcs0012,
easily within the reach of HST/FGS fringe tracking astrometry. The
proposed observations will yield a planetary mass, rather than, as
previous investigations have done, only suggest a planetary mass


Boron in stars of same O and Li, but different Be: testing cosmic-ray
vs. neutrino spallation

We propose to further investigate the origin of the light elements Li,
Be, and B, by observing B in a group of galactic stars found to have
similar O abundances but to differ significantly in their Be content.
Contrary to Li, which is produced in the Big Bang and its abundance in
halo stars constrains primordial nucleosynthesis and the baryonic
density, Be and B are produced later by cosmic ray spallation as the
galactic halo forms. Knowledge of their evolution is now being used
along with that of [O/H] {and [Fe/H]} as a powerful discriminant
between different models of the chemical and dynamical evolution of
the galaxy. Light element abundances can be used to test these
theories only if they have not been altered by destruction in stars.
Recently we have identified a small number of stars characterised by
the same O abundance but large differences in their Be content, which
cannot be accounted for by stellar depletion {since their Li is
undepleted}. As neutrino-spallation contributes only to the production
of isotope 11 of B, and not to Be, Be and B abundanes in the same
stars will allow us to see if B scales with Be {evidence for a CR
spallation origin} or with O {evidence for contribution from neutrino

FGS 9888

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. All of this can be achieved in the next few years with
HST, without having to wait for the technically demanding and risky
SIM and GAIA missions well into the next decade.

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
0.7<z<1.9, 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.

STIS 9855

Exploring Interstellar Krypton Abundance Variations at Kiloparsec

We propose to obtain high-resolution STIS echelle observations of the
interstellar Kr I 1236 absorption toward eight stars situated in the
Galactic disk beyond the Carina/Sagittarius or Perseus Arms. The
measurement of interstellar krypton abundances is a relatively simple
way to investigate elemental abundance variations in the Galaxy, since
its dominant form is neutral and it is undepleted in the ISM.
Furthermore, the intrinsic strengths of krypton’s UV resonance lines
combined with its low relative abundance to hydrogen produce weak,
unsaturated features in typical Galactic sight lines. Previous GHRS
and STIS measurements have demonstrated that Kr/H abundance ratios
within the local spiral arm, the Orion Spur, are remarkably uniform;
however, anomalously high krypton abundances have been measured for
the only two sight lines extending also through gas outside the Orion
Spur. This program is designed to determine whether these sight lines
are isolated cases of enrichment, or if they are representative of
large scale krypton abundance variations outside the local arm. Since
krypton is undepleted in the ISM, these observations will also be
relevant to the study of total elemental abundance and depletion
variations for a variety of elements with resonance lines between 1170
and 1372 Angstroms.


The Upper End of the Supermassive Black Hole Mass Function: Pushing
the 10 Billion Solar Mass Limit.

In 1994, HST provided the first secure detection of a supermassive
black hole {SBH} in a galactic nucleus. The galaxy was M87, the black
hole almost 4 billion solar masses. Since then, two dozen additional
SBH detections have been the outcome of the several hundred orbits of
HST time devoted to this cause. Yet, M87’s black hole is still the
most massive known, and in only two other galaxies have SBHs in excess
of a billion solar masses been detected. The aim of this proposal is
to characterize the high mass end of the local SBH mass function. Four
brightest cluster galaxies have been carefully selected. Their large
masses, luminosites and stellar velocity dispersions, as well as their
having a merging history which is unmatched by galaxies in less
crowded environments, make these galaxies the most promising hosts of
the most massive SBHs in the local Universe. It is in the high mass
regime that the unavoidable link between the evolution of supermassive
black holes and the hierarchical build-up of galaxies leaves its
clearest signature. It is these galaxies that are expected to be the
relicts of the most luminous high redshift quasars, those so
spectacularly targeted by the Sloan Digital Sky Survey. Expanding {and
extending} the high mass end of the local SBH mass function is the
next obligatory step we need to take to improve our understanding of
how SBHs, and their hosts, formed and evolved.

NIC1 9833

T Dwarf Companions: Searching for the Coldest Brown Dwarfs

Faint companions to known stars have historically led to the discovery
of new classes of stellar and substellar objects. Because these
discoveries are typically limited by the flux ratio of the components
in the system, the intrinsically faintest companions are most
effectively identified around the intrinsically faintest primaries. We
propose to use NICMOS to image a sample of 22 of the coolest known
{T-type} brown dwarfs in the Solar Neighborhood in order to search for
fainter and cooler brown dwarf companions. The high spatial resolution
of the NIC 1 detector enables us to distinguish binary systems with
apparent separations greater than 0"08, or physical separations
greater than 1.2 AU at the nominal distances of the objects in our
sample. Furthermore, the substantial sensitivity of NICMOS imaging
allows us to probe companion masses of 5-50 Jupiter masses and
companion effective temperatures of 250-1300 K in a maximally
efficient manner. Based on work to date, we expect that roughly 20% of
the objects in our sample will be binary, and that one or two of these
will likely harbor a significantly fainter secondary. Hence, we expect
to find a companion cooler than any currently known brown dwarf, a
potential prototype for the next spectral class. In addition, our
investigation will add substantially to the sample of known binary
brown dwarfs, allowing improved statistical analyses of the binary
fraction, separation distribution, and mass ratio distribution of
these systems, key quantities for probing brown dwarf formation. We
will also identify optimal substellar systems for astrometric mass
measurements, a critical check for theoretical models of brown dwarfs
and extrasolar planets.

STIS/MA2 9804

Experimental Proof of the Neutrino Process in SN from Boron Isotope

The light elements Li, Be, and B are formed in the Big Bang {Li} and
by Cosmic Ray {CR} spallation. But the abundance of 11B has never been
satisfactorily explained: 11B/10B in the solar system is 4.0, CR
spallation predicts 2.5. There needs to be another source of 11B.
Woosely et al. {1990} predict the large flux of neutrinos in Type II
supernovae will sythesize elements, including converting 12C to 11B.
This "neutrino process" has never been experimentally verified. A
"smoking gun" would be to find a metal poor star whose elements came
primarily from Type II SN and whose B is pure 11B — only the neutrino
process could produce that. In a previous cycle we obtained STIS
measurements of a metal poor star and were able to clearly show that
11B/10B <= 4. We now ask for additional observations of higher S/N,
which can distinguish if 11B/10B = 4, or if the mix is pure 11B. In
either case we will end up with a precise measure of how much 11B in
old stars is NOT produced by CRs, and likely due to SN, and can place
a new constraint on the temperature and density of SN models in the
region where neutrino-induced nucleosynthesis is thought to take
place. Although this test could be made in a single star, we ask to
observe two, to increase the confidence in what is a subtle isotopic
measurement. We propose to observe the brightest two suitable metal
poor stars. One is in the CVZ.

ACS 9799

A Snapshot Survey of Galactic Bulge Globular Clusters

The globular clusters toward the Galactic bulge remain among the least
studied of the Galaxy’s globular clusters, primarily because severe
photometric crowding has hindered ground-based imaging. We propose a
snapshot survey {3 month proprietary period} using ACS onboard HST to
produce a complete sample of color-magnitude diagrams for these
clusters. The high spatial resolution of HST gives photometry vastly
superior to even the best ground-based color-magnitude diagrams.
Measurement of the horizontal and red giant branches gives reddening
and distance, from which physical parameters for the clusters are
derived. Ages to be derived are of special interest because this
population may contain the oldest clusters in the Galaxy.
Additionally, the separation of cluster members from contaminating
field stars will give far superior structural parameters than can be
derived from the ground. Many of these clusters have especially
concentrated cores; due to their proximity to the Galactic Center,
they may have experienced far greater dynamical evolution due to bulge
shocking. If stellar encounters are capable of modifying stellar
populations, these clusters probably are the best place to look for
such effects. Because ground-based study of these clusters has been so
difficult, we believe that this survey is potentially an important
part of HST’s legacy.


Observations of Intermediate Mass Black Hole Candidate Ultra-Luminous
X-ray Sources

Ultra-luminous X-ray {ULX} sources are off-nuclear point sources in
nearby normal galaxies. Variability observed on the timescale of days,
weeks, and years signals that ULXS are accreting sources, likely
harboring black holes. However, the observed X-ray luminosity of these
systems far exceeds the Eddington limit for a 10 Msun black hole; some
ULXs may be intermediate mass black holes. The identification and
study of optical counterparts with HST will be central to better
understanding these objects. We propose to obtain deep U-B-V-I
exposures of 4 extremely bright ULXs in nearby spirals: NGC 1313 X-1
and X-2, M81 X-9 {Holmberg II X-1}, and M74 X-1. Each has a 0.5”
Chandra position, and X-ray luminosity and spectral characteristics
consistent with expectations for intermediate mass black holes. We
will use the colors we obtain, the magnitudes we measure, and any
source variability {also, correlated optical-X-ray variability from
simultaneous Chandra snapshots} to constrain the nature of the donor
stars and the black holes {10 Msun or 100-1000 Msun}, and the
formation and evolution scenarios for each system.

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.


Calibrating the Black Hole Mass Scale for Quasars

We propose to obtain ACS/WFC imaging of all 17 low-redshift quasars
that have black hole masses measured from reverberation mapping. This
is a key sample since all secondary methods to estimate black hole
mass in quasars depend on this local reverberation-mapped sample for
their calibration. The best external check on reverberation mapping is
whether it gives results that are consistent with the black hole mass-
host galaxy correlations of nearby galaxies. For local Seyfert
galaxies the reverberation masses appear consistent with the M-sigma
correlation, but it is not known whether this also holds true for
quasars because the stellar velocity dispersions of quasar hosts are
virtually impossible to measure. We will use the ACS data to measure
accurate bulge parameters {luminosity and effective radius} for the
host galaxies of the reverberation-mapped quasars. From the
fundamental plane or the Faber-Jackson relation, we can estimate the
host galaxy velocity dispersion and test whether the reverberation
masses follow the M-sigma relation even for objects with quasar
luminosities. This is a crucial test if we are to trust the
reverberation masses as the lowest rung on a "distance ladder" of
black hole mass estimators for quasars, so that quasars can be used to
trace the cosmological growth history of black holes. {Note added in
Phase II: the TAC awarded us 8 orbits to observe 7 quasars and a PSF

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 {V>17.5}. 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 9701

ACS Default {Archival} Pure Parallel Program II

The proposal is designed to test ACS pure parallels in POMS.

ACS/WFC 9575

Default {Archival} Pure Parallel Program.

The Advanced Camera for Surveys (WFC) was used to test ACS pure
parallels in POMS.

ACS/WFPC2 9488

Cosmic Shear – with ACS Pure Parallel Observations

The ACS, with greater sensitivity and sky coverage, will extend our
ability to measure the weak gravitational lensing of galaxy images
caused by the large scale distribution of dark matter. We propose to
use the ACS in pure parallel {non- proprietary} mode, following the
guidelines of the ACS Default Pure Parallel Program. Using the HST
Medium Deep Survey WFPC2 database we have measured cosmic shear at
arc-min angular scales. The MDS image parameters, in particular the
galaxy orientations and axis ratios, are such that any residual
corrections due to errors in the PSF or jitter are much smaller than
the measured signal. This situation is in stark contrast with
ground-based observations. We have also developed a statistical
analysis procedure to derive unbiased estimates of cosmic shear from a
large number of fields, each of which has a very small number of
galaxies. We have therefore set the stage for measurements with the
ACS at fainter apparent magnitudes and smaller, 10 arc-second scales
corresponding to larger cosmological distances. We will adapt existing
MDS WFPC2 maximum likelihood galaxy image analysis algorithms to work
with the ACS. The analysis would also yield an online database similar
to that in


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.

WFPC2 10090

WFII backup parallel archive proposal

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

STIS/CCD 10085

STIS Pure Parallel Imaging Program: Cycle 12

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

WFPC2 10084

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.

WFPC2 10070

WFPC2 CYCLE 12 Supplemental Darks Part 2/3

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

WFPC2 10067

WFPC2 Cycle 12 Decontaminations and Associated Observations

This proposal is for the monthly WFPC2 decons. Also included are
instrument monitors tied to decons: photometric stability check, focus
monitor, pre- and post-decon internals {bias, intflats, kspots, &
darks}, UV throughput check, VISFLAT sweep, and internal UV flat


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 1×1, 1×2, 2×1, and 2×2 bin settings at gain=1,
and 1×1 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.


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



                           SCHEDULED     SUCCESSFUL    FAILURE TIMES
FGS GSacq               20                       20
FGS REacq               24                       24
FHST Update             51                       51


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