yee@trident.arc.nasa.gov (Peter E. Yee) (07/20/89)
Paula Clegget-Haleim
Headquarters, Washington, D.C. July 19, 1989
Ray Villard
Space Telescope Science Institute, Baltimore, Md.
RELEASE: 89-121
SCIENCE OBSERVATIONS SELECTED FOR NASA/ESA HUBBLE SPACE TELESCOPE
The Space Telescope Science Institute, Baltimore, Md., has
completed selection of the first science observation proposals
from the astronomy community to be carried out using the
NASA/European Space Agency (ESA) Hubble Space TelescopeMd
The Hubble Space Telescope (HST), scheduled for launch in
March 1990, is the first major international optical telescope to
be permanently stationed in low-Earth orbit. Capable of viewing
the universe with a tenfold greater resolution than ground based
observatories, the HST has a tremendous potential for fundamental
scientific breakthroughs in astronomy. Observing opportunities
on the powerful space facility are open to the worldwide
astronomical community.
"It is exciting to see the many excellant proposals and to
think of the scientific discoveries that will soon emerge when
the Hubble Space Telescope uncovers the mysteries of fundamental
scientific questions," says Neta Bahcall, Head of the institute's
Science Programs Selection Office.
The selected observations will make use of HST's unique
capabilities to study a wide variety of astronomical objects,
from nearby planets to the horizon of the visible universe. The
observations should help to dramatically improve current
understanding of the size, structure and evolution of the
universe.
Among the accepted proposals are plans to search for black
holes in neighboring galaxies, to survey the dense cores of
globular star clusters, to better see the most distant galaxies
in the universe, to probe the mysterious core of the Milky Way
galaxy and to search for neutron stars that may trigger bizarre
gamma-ray bursts.
The 162 proposals were accepted following an intensive
scientific peer review of 556 proposals submitted by astronomers
from 30 countries. Approximately 20 percent of the proposals
were from member nations of the European Space Agency, a joint
partner with NASA on the HST project.
The HST is such a powerful, new resource for optical
astronomy, that observing time was heavily oversubscribed.
During the first 12-month observing cycle, 11,000 hours of
observing time were requested, with only 1200 hours available.
The average length of an accepted observation is 10 hours.
"Unfortunately, because of the high oversubscription rate,
many excellent proposals could not be accommodated," says
Bahcall. "We expect that the available observing time will be
somewhat larger in the second cycle, due to a higher anticipated
HST observing efficiency and a lower fraction of time committed
to guaranteed time observers (GTO)."
When HST is launched, it will undergo a 7 month check-out
and instrument calibration period. During that time some of the
first science observations will be made by the GTOs. They are
the astronomers on the six teams which developed HST
instrumentation, as well those astronomers who contributed to the
design of the 12-ton observatory.
General observer proposals will begin 7 months after launch
and most will be completed within a 12-month period, though a few
key projects will be extended over 3 years. Slightly more than
half of HST's observing time for the first year of operation will
be available for general observers. The remainder of the
observing time will be used by the GTO's.
To utilize every moment of observing time and hence maximize
efficiency, HST is "over-booked" with accepted general observer
proposals by a ratio of 3:1. One hundred eight accepted
proposals are high priority and represent 90 percent of HST
observing time. The remaining 54 supplemental proposals
essentially "fly standby." They will only be executed if
appropriate scheduling opportunities arise.
Sixty-two scientists including 10 from ESA member nations
participated in the proposal review and selection process. The
scientists were divided into six peer-review panels which covered
sub-disciplines in astronomy such as solar system, stellar
astrophysics, stellar populations, interstellar medium, galaxies
and clusters, quasars and active galactic nuclei.
Each proposal was judged primarily for scientific
importance. Other selection criteria took into account such
factors as the technical feasibility of the proposal and an
observer's need for the unique capabilities of HST.
The ranked lists of proposals assembled by the various
panels were then reviewed by a cross-discipline Time Allocation
Committee (TAC). Space Telescope Science Institute Director
Riccardo Giacconi made the final selection based upon a review of
the TAC's recommended list of proposals.
The proposals now will go through a phase II process where
the guest observers will specify the technical details of their
observations. The proposals then will be checked for technical
feasibility, such as availability of guide stars required to aim
the telescope in space and other possible problems. At the
conclusion of phase II this fall, a catalog of approved
observations will be made available.
The Space Telescope Science Institute is operated for NASA
under a contract with the Goddard Space Flight Center, Greenbelt,
Md., by the Association of Universities for Research in
Astronomy, Inc. The institute is located on the Johns Hopkins
University campus in Baltimore, Md.rehrauer@apollo.COM (Steve Rehrauer) (07/24/89)
In article <28843@ames.arc.nasa.gov> yee@trident.arc.nasa.gov (Peter E. Yee) writes: [...much about the Hubble Space Telescope...] > The HST is such a powerful, new resource for optical >astronomy, that observing time was heavily oversubscribed. >During the first 12-month observing cycle, 11,000 hours of >observing time were requested, with only 1200 hours available. >The average length of an accepted observation is 10 hours. Time for a naive question. Does this 12-month observing period include the 7 months' worth of checkout time? If not, why on (or off :-) Earth are there only 1200 hours of observation time available? Is this the time that has been allotted for such use, or total available time? If the latter, why only 50 days' worth? (Hey, I *said* it was naive!) -- >>> "Aaiiyeeeee! Death from above!" <<< | Steve Rehrauer Fone: (508)256-6600 x6168 | Apollo Computer, a ARPA: rehrauer@apollo.com | division of Hewlett-Packard "Look, Max: 'Pressurized cheese in a can'. Even _WE_ wouldn't eat that!"