ASTRONOMY IN ANTARCTICA

			    Michael Burton

The astrophysics group is embarking on an ambitious project which has
as its ultimate goal the construction of an astronomical observatory on
the highest part of the Antarctic Plateau.  You might wonder why we
should want to contemplate such an endeavour, to go to the remotest
corner of the globe in order to further our discipline? This short
article will try to enlighten you of the rationale behind the project.

In the continual quest to improve on sensitivity levels, to obtain data
only limited by the natural celestial background radiation arriving at
the Earth, rather than by artificial limitations imposed by our
immediate surroundings, astronomers have focused on three areas:
building larger telescopes, constructing better instruments and moving
to superior sites. Engineering limitations prevent us from improving
significantly on the new generation of 8m telescopes currently under
construction.  Detector efficiencies are now close to 100%. This leaves
the site as the major area where we can improve on current abilities.
For the past two deacdes astronomers have been concentrating their
major facilities on the top of high mountains in desert ranges or on
isolated ocean islands, such as Mauna Kea in Hawaii, where the air is
dry and the atmosphere stable. Ultimately, of course, the best possible
observing site will be from a space-based platform, such as an in-orbit
satellite or a Moon base. But the cost of such an

The highest part of the Plateau, Dome A, is over 4000m high and in the
middle of the Australian Antarctic Territory.  The air is incredibly
dry, with typically only about 25% the amount of waper vapour present
in the atmosphere as on the best nights from even a good site like
Mauna Kea.  It is, of course, incredibly cold, with winter temperatures
falling as low as 90 degrees below zero (in fact it is probably better
to talk in Kelvin and say about 180K!).  The air is still, as the
katabatic winds essentially start at the highest part of the Plateau
and cascade off it, creating the gales we are familiar with on the
Antarctic coast.  These conditions provide three principle gains for
astronomy over any other ground based site.  Firstly, the dry air means
consierably improves the atmospheric transmission in the infrared and
millimetre wavebands, opening up new windows to explore the Cosmos.
There are a wealth of spectral lines from interstellar atoms and
molecules that will be observable for the first time. Sec

That is the theory, but we have a long way to go to turn this concept
into a reality. That is the challenge we are embarking on now. We are
currently engaged in site testing activities, focussed initially at the
South Pole (to which there is relatively easy access), in conjunction
with our US and French collaborators. Michael Ashley's article will
describe the progress we are making in an experiment to measure the
infrared properties of the South Pole site.  A new graduate student,
Rodney Marks, is also involevd in an experiment to measure the site
seeing at the South Pole, and is currently in Nice working with one of
the world's experts in this area, Dr. Jean Vernin, to learn the
techniques. Our initial aim is simply to verify that all the reasons we
believe make the Antarctic Plateau the premier site in the world for
conducting astronomy are in fact true, and to understand the conditions
we have to face so that we can meet the supreme technical challenge of
constructing and operating an observatory there.