This Echo is READ ONLY !   NO Un-Authorized Messages Please!
 ~~~~~~~~~~~~~~~~~~~~~~~~   ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

30 April 2003

HUBBLE SPACE TELESCOPE

DAILY REPORT        # 3352

PERIOD COVERED: DOY 119 (partial day observations due to safemode
event-see SIGNIFICANT EVENTS section)

Part 1 of 3

OBSERVATIONS SCHEDULED

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.

ACS/WFC 9351

Determining Hubble's Constant from Observations of Cepheids in the
Host Galaxy of SN Ia 1994ae

the host spiral galaxy NGC 3370. Modern CCD photometry has yielded an
extremely tight Hubble diagram for SNe Ia with a precisely determined
intercept {i.e., Delta H_0/H_0} 1 measurement of the true Hubble
constant is still limited by the calibration. The HST calibration of
all but a few SNe Ia observed to date is significantly compromised by
the systematics of photographic photometry and host galaxy
extinction, as well as by the photometric uncertainties associated
with WFPC2. In contrast, SN 1994ae is one of the very best-observed
SNe Ia with CCD photometry. The exquisite B, V, R, and I light curves
are well-sampled beginning 10 days before maximum brightness, and
they indicate little reddening. From our supernova photometry and the
current provisional SN Ia calibration we would find a distance of
30 +/- 2.1 Mpc, well within the range where ACS can accurately
observe Cepheid light curves and distinguish Cepheids from
nonvariable stars. 

HST 9382

A Large Targeted Survey for z < 1.6 Damped Lyman Alpha Lines in SDSS
QSO MgII-FeII Systems.

We have searched the first public release of SDSS QSO spectra for
low-z {z<1.65} metal absorption lines and found over 200 large rest
equivalent width MgII-FeII systems. Previously, we empirically showed
that such systems are good tracers of large neutral gas columns,
with ~50% being classical damped Lyman alpha {DLA} systems
{N_HI>=2*10^20 cm^-2}. Here we propose to follow up a well-defined
subset of 79 of them to search for DLAs with 0.47 * Origin: SpaceBase(tm) Pt 1 -14.4- Van BC Canada 604-473-9358 (1:153/719.1)

SEEN-BY: 633/267 270

@PATH: 153/719 715 7715 140/1 106/2000 633/267