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.
There are a number of other compelling reasons that lead one toward
the concept of remote observing. The scheduling of observing time on
the Keck
Telescope
is done
on the basis of proposals submitted by scientists from the member
institutions and there is a large over-subscription ratio. This
results in observing runs that are short, typically 2 nights. A
typical project involves several people, and while the number of
people who travel to
Hawaii
for a given
night varies widely from project to project, the average is 2 to 3
people. This means substantial sums are spent by the member
institutions on travel and related expenses. It also means that with
these short runs the salary cost for ``wasted time'' during travel or
while acclimatizing to the altitude is very large.
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 will be possible for one part of the team to concentrate on obtaining the observations, another person can be analyzing the scientific results from the last integration, another can be checking the instrumental performance to make sure everything is working correctly (particularly the detector), and a fourth group of people can be checking 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 and more routine when no travel is required, they don't need to miss classes, etc.
Astronomical images are large. The optical instruments currently in use at the Keck Telescope have frames that are 8 Megabytes in size, and soon these arrays will become 3 times larger. Integration times depend on the scientific program, and range from less than a second to an hour. The quality of ground based optical and infrared astronomy observations is very sensitive to weather conditions, including clouds and atmospheric turbulence. Hence, although observing sessions may be planned in detail in advance, careful quick-look on-the-spot analysis of each image is important in defining what to do next, how long the next exposure should be, whether to switch to brighter objects due to poor sky conditions, how to modify the program to cope with unexpected failures of non-critical telescope or instrument components, etc.
Remote diagnosis of problems becomes feasible once a high speed network exists. The teams that built the instruments for the Keck Telescope are located at Caltech or a campus of the University of California. These engineers cannot rush off to Hawaii with no notice when there is a problem that the staff in Hawaii feel they cannot resolve. With a high speed network, the engineers in California can test the operation of the equipment remotely, see the results of these tests essentially instantaneously, and diagnose the problem quickly.
Remote software development and debugging will also become feasible again with such a high speed network. During the early stages of construction of the instruments, some efforts along these lines were done across the Internet link between California and the Keck summit, but over the past 3 years that link has become so saturated with traffic and so slow as to be completely useless. Again both travel and time are saved, and effective help from highly skilled and experienced people in California can be obtained quickly when necessary.