Imaging the Invisible
with Grainger Observatory's stellar new robotic
The spheres were in alignment this February, for the Academy's new robotic
telescope was up and running just in time for science instructor Chris
Harper's astronomy classes to use it on a newly discovered star. With
the new telescope, Harper's students were able to collect and study digital
images of Supernova 2002ap, which would have been difficult, if not impossible,
to see through the observatory's other telescopes.
The Academy's Grainger Observatory is a member of the American Association
of Variable Star Observers, a worldwide interface between professional
and amateur astron-omers. Harper believes that "one of the great things
about the astronomy program at PEA is that it is a science in which students
can really make observations that are valuable to professionals in the
Adding the telescope to the Academy's constellation of instruments has
meant a great deal of collaboration between astronomy instructors Harper
and Emily James, who wrote the grant proposal and shepherded the project,
their students, members of the information technology and facilities management
departments, and Jerry Gunn, an outside specialist who designed the telescope's
systems. The Grainger Foundation, which had made possible much of the
existing observatory and its equipment, agreed to fund it.
A third dome at the observatory
A third dome at the observatory The robotic telescope makes the third
and central "dome" at the observatory, though its roof is a pyramid. The
eight-inch reflector telescope's automated dome, robotically controlled
mount and charged coupling device (CCD) camera are all connected to the
Academy network. All of these systems can be operated from a computer
in the dome or from terminals in the chart house and Phelps Science CenterŅor
conceivably from anywhere in the world. Operating a telescope from indoors
is a novelty for PEA astronomers. When the telescope was first being tested
from the chart house, one of Harper's students said it "felt like cheating"
to be warm and indoors while making a mid-winter observation.
The robotic telescope has a narrower field of view than the other two
large telescopes on campus. But the precision of its electronically controlled
movement, its ability to automatically slew, or swivel, to and track an
object in the sky and the camera's very efficient use of available light
(it captures 90 percent, as opposed to the 15 percent captured by a normal
camera) make it a valuable specialized tool. To find an object in the
sky, the operator can select from an existing "menu" of hundreds of objects
that Gunn has programmed into the system, or enter coordinates from a
star chart. The robotic system automatically opens the dome and moves
the telescope into position; the CCD camera makes digital images on command.
A weather station in the dome detects cloud cover, wind speed, available
light and temperature to prevent damage to the telescope or the dome when
it is being operated remotely. While the operator does not get a live
picture of what the telescope is "seeing," the digital images it takes
are instantly visible on the computer.