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the programs and facilities needed to carry out this
work. Any exercise of this kind is based on certain
assumptions, and it is important to state clearly what
these are. We have taken as our point of departure pro-
grams that would begin in fiscal year 1983 or later, and
we have not evaluated ongoing programs approved by pre-
vious advisory committees. The most important such
project in radio astronomy is the 25-m millimeter-wave
telescope proposed by the NRAO and appearing in the
President's original budget for fiscal year 1981 but
subsequently removed for budgetary reasons. A large
millimeter-wave telescope was one of the high-priority
recommendations of the previous astronomy survey (the
Greenstein report), and the 25-m project has been
thoroughly reviewed and approved by the advisory mech-
anisms of the National Science Foundation. The present
report of the Panel on Radio Astronomy is predicated on
the assumption that the 25-m telescope will be con-
structed during the early or middle Years of the 1980's.
II. SUMMARY OF RECOMMENDATIONS
A. Highest Priority
The Panel selected four facilities as being of the
highest priority for radio astronomy in the 1980's. In
order of importance these are:
1. A Very-Long-Baseline (VLB) Interferometric Array
of about ten 25-m antennas widely spread over the United
States, designed to form radio images at ultrahigh angular
resolution of quasars, galactic nuclei, interstellar
masers, and a variety of stellar sources and to extend
measurements of proper motion and statistical parallax
over much of the Galaxy. The resolution of this Array at
its shortest operating wavelength of about 1 cm will be
only 0.3 milliarcsecond--several orders of magnitude
better than that of any other image-forming astronomical
telescope.
2. A submillimeter telescope of about 10-m aperture
located at a dry, high-altitude site. The purpose of
this telescope is to open the almost unobserved wave-
length range from 0.3 to 1.0 mm to astronomical investi-
gation. Molecular line emission in this region may
approach the Fraunhofer spectrum of the Sun in richness,
and there is a variety of continuum sources including the
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planets, interstellar dust clouds, quasars, radio sources
and the cosmic background radiation.
3. A near-Earth-orbiting verY-long-baseline-inter-
ferometrY VLBI station consisting of a deployable tele-
scope in the 25-m class. As a rapidly moving additional
element of the ground-based Array, this station will sig-
nificantly enhance the angular resolution, dynamic range,
latitude coverage, and time response of the system, and
it will serve as a prototype for stations in highly ellip-
tical orbit projected for the 1990's.
4. A large steerable radio telescope in the 100-m
class designed to operate at wavelengths of 1 cm and
longer. The equivalent of a large optical reflecting
telescope, this general-purpose instrument combines large
collecting area with wide frequency coverage and has
important applications in nearly every area of radio
astronomy. These include studies of the Sun, Moon,
planets, pulsars, distant 21-cm galaxies, molecular
clouds in our own and other galaxies, and the cosmic
background radiation.
Special Category
5. The Panel recommends the construction of a two-
element heterodyne interferometer to observe through the
10- m atmospheric window. The purpose of this
instrument is to resolve stars and other small infrared
sources, to study circumstellar dust and molecules, and
to undertake precision astrometry, including testing of
the General meory of Relativity.
B. Other Recommendations
The Panel identified the following projects as being of
major importance to radio astronomy but of less urgency
than the above:
6. A program of antenna and receiver development for
a 10-m-class submillimeter telescope in near-Earth orbit,
to be launched in the 1990's.
7e The inclusion of radio spectrographs and polari-
meters on the Star Probe and Solar Coronal Explorer, to
observe plasma processes in the solar corona and the
solar wind.
8. A millimeter-wave telescope in the 5-10-m class in
the southern hemisphere for the study of galactic struc-
ture and molecular sources not visible from the United
States.
Representative terms from entire chapter:
background radiation
