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Remote use of astronomical telescopes has been a topic of interest for
many years, even before space-based observing platforms (e.g.,
IUE
) began
to demonstrate total remote operation out of sheer necessity.
Initially, a number of ground-based radio and optical telescopes
(e.g., the WIYN
Telescope
[8])
introduced queue-based scheduling, a mixture of remote and interactive
observing modes. Only very recently are optical telescopes beginning
to realize the benefits of true remote observing: for example,
observations with modest size detectors at Apache
Point Observatory
are being carried out
remotely using the Internet [11]. For this project, we have
established remote interactive observing capabilities for
Keck Observatory
on Mauna
Kea
for observers at
Caltech
, in
Pasadena
,
California. The recently commissioned twin 10-meter Keck Telescopes
are the largest optical/infrared telescopes in the world and thereby
typify the data and network requirements of a modern observatory. In
undertaking this project, we were motivated by several operational and
scientific advantages that remote observing would offer.
One primary concern is the high altitude of the Keck Observatory. At
an elevation of 13,600 feet, the summit of Mauna Kea is a demanding
location for both mental and physical exertion. In spite of the
requirement that all astronomers spend a night at Hale Pohaku
(altitude 
9000 feet) for acclimatization before proceeding to
the summit for a night of observing, about 15% of the people who do
not observe often at Mauna Kea become sufficiently ill during the
course of a 3 night run that they have to leave the summit for at
least 12 hours. Approximately 75% of the people coming to the summit
to observe for a full night experience some discomfort such as a mild
headache, and almost all experience some loss of judgment,
irritability, etc. Remote observing provides an environment for all
observers that is free of these difficulties, and also provides an
opportunity for people who cannot tolerate high altitudes (e.g.,
pregnant women, those with heart conditions, etc.) to observe with the
Keck Telescopes.
Another logistic motivation for remote observing involves monetary
issues common to large telescopes located at sites distant from the
home institutions: In general, the larger the telescope, the more
heavily over-subscribed it is. Runs are therefore often only 1 or 2
nights in duration. Since 2-3 observers come to each run, this means
substantial sums of money are spent on travel and related expenses.
The additional night of acclimatization for high-altitude sites such
as Mauna Kea increases the cost further. Finally, the salary cost for
``wasted time'' during these runs is quite large. An excellent
example of the potential savings is that of the
European Southern Observatory
(ESO)
: There are 19 telescopes near the
Atacama desert in Chile, including two 3.6-meter telescopes and a set
of four 8-meter giants currently under construction (the
Very Large
Telescope
, or VLT). The observing
site is widely regarding as one of the very best in the world, yet it
is half-way around the globe from most of its large European user
population. Understandably, remote observing is gaining popularity
among European astronomers [12].
Remote diagnosis of hardware and software problems also becomes more
feasible with an operational remote observing system. In the case of
Keck Observatory, the teams that built the instrument hardware and
software are located at Caltech or a campus of the University of
California. Just their presence in the same buildings as the remote
observers can be extremely helpful when problems arise in the
operation of the telescope. The establishment of remote observing
from California implies the presence of a network connection, which
can allow engineers and programmers to analyze the remote systems
essentially instantaneously. Again, both travel and time are saved,
and effective help from highly skilled and experienced people in
California can be obtained quickly when necessary.
In addition to these operational advantages, there are strong
scientific advantages to remote observing as well. With remote
observing, every member of a large collaboration can participate in
obtaining the data. It is possible for one part of the team to
concentrate on obtaining the observations, while other team members
can be analyzing the scientific results from the last observation,
checking the instrumental performance to make sure everything is
working correctly (particularly the detector), or browsing the
literature or catalogs of objects as necessary to prepare for the next
set of observations. The inclusion of students in the observing
session becomes much easier, cheaper, and more routine when no travel
is required, i.e., they don't need to miss classes. The facilities
available at remote observing sites (e.g., Caltech) usually far exceed
those available at the observatory site, whether it be computer
hardware, office and library supplies, or a pizza delivery. Recall
also that the remote site may be located such that the night hours of
observing overlap, or even coincide with standard business hours at
the remote site.
Next: Network Requirements
Up: OVERVIEW
Previous: OVERVIEW
Patrick Shopbell
3/17/1998