Daily # 4289

HUBBLE SPACE TELESCOPE - Continuing to collect World Class Science

DAILY REPORT # 4289

PERIOD COVERED: UT January 30, 2007 (DOY 030)

OBSERVATIONS SCHEDULED

WFPC2 10822

CIII] Imagery of Planetary Nebulae

We propose to image five planetary nebulae {PNe} with the F185W filter
of WFPC2 in order to study the spatial distribution of the ultraviolet
C III] 1909 Angstrom line relative to [O III] 5007 Angstrom and other
optical lines. This program follows a Cycle 12 SNAP program {GO 9740}
of WFPC2 F185W imaging of PNe and H II regions which validated the
feasibility of obtaining images of bright PNe in C III] through
careful continuum subtraction and calibrations based on archival IUE
SWP and LWP/R spectra. However, in the SNAP program only short {10
minute} exposures of four PNe were taken; we now propose much longer
exposures {60-72 minutes} to obtain the desired signal-to-noise to
develop high quality C++ ionization maps for comparison with O++ and
other ions via photoionization modeling. The five PNe chosen: NGC
2392, NGC 3242, NGC 6543, NGC 6720, and NGC 7662 were selected on the
basis of their high surface brightness, extensive UV spectra available
from IUE and HST, and numerous WFPC2 images in the archives in other
emission lines. We expect the results of this study to impact the
utility and accuracy of using the C III] 1909 lines compared to [O
III] 5007 for C/O abundance derivations in PNe and H II regions.

FLIGHT OPERATIONS SUMMARY:

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

HSTARS: (None)

COMPLETED OPS REQUEST: (None)

COMPLETED OPS NOTES: (None)

SCHEDULED SUCCESSFUL
FGS GSacq 02 02
FGS REacq 02 02
OBAD with Maneuver 08 08

SIGNIFICANT EVENTS:

NCS Cool down status update - out of surge

The compressor left software-defined surge at approximately 030/09:50
UTC, when the Turbine Inlet temperature dropped below 82 K. The PID
control law ramped the compressor up to 7300 rps, the maximum
commanded speed outside surge. Physical surge behavior had abated
about 2 hours earlier when the Turbine Inlet temperature was reading
86 K.

As of 030/11:00 UTC all cryogenic loop temperatures are below 100 K.
The cool down is proceeding at a steady but slowing pace. The PID
Control Point temperature is less than 15 degrees above its final set
point. Monitoring of the cool down will continue on an as-needed
basis.