Sky and Telescope - March 2016 - 27

NASA

OVERSIZED CARRY-ON SOFIA is a modiﬁed Boeing 747 that ﬂies high above the atmospheric water vapor that interferes with
ground-based telescopes. Its 2.5-meter reﬂecting telescope peeks out from the rear fuselage.

JOY POLLARD / GEMINI OBSERVATORY / AURA

SOFIA is a modiﬁed jetliner with a 2.5-meter telescope installed in its rear fuselage. It ﬂies above most
of Earth's atmospheric water vapor, collecting infrared
photons that would otherwise be absorbed by water. The
aircraft is based in Palmdale, California, but its ﬂights,
which last about 10 hours, often take its crew far over
the continental United States, the Paciﬁc, Canada, or
beyond; two summers ago, they deployed to New Zealand. Working on an airplane, instead of in a windowless
control room, has allowed Saurage to see spectacular
astronomical sights, such as the aurora at both poles.
Unlike on the ground, where TOs usually operate solo,
TOs onboard SOFIA work in pairs during an observing
session. One TO is responsible for locating the target in
the sky and keeping the target centered in the telescope's
ﬁeld of view, a challenge when SOFIA encounters air
turbulence. The other TO communicates with scientists

SCREENS GALORE Telescope operators keep their eyes
on many systems during observations. Among the windows
displayed here at Gemini North are telescope and dome
controls, weather parameters, and observing results.

about the goals of the observing session, checks the quality of incoming data, and makes sure that the telescope
and instruments are functioning properly.
SOFIA has certain advantages of both a ground-based
telescope and a space-based telescope, which aﬀect how
Saurage functions as a TO. "We get up to the edge of the
stratosphere and thereby above most weather and in a
region best suited for far-infrared observations, but then
again we can come home every day for repairs, upgrades,
and, importantly, switching instruments," she explains.
"We are never limited by hardware or weather."
But Saurage ﬁnds that her work is more demanding than at other observatories she's worked at, simply
because the telescope and its instruments are aboard a
ﬂying airplane. "There are the familiar set of commands
most telescope operators use to manipulate the telescope
- slewing, tracking, and guiding to set up on the desired
ﬁeld," she says. But since they're on a plane, she adds, they
have to coordinate with a host of aviation concerns. While
a ground-based observing session is aﬀected by weather,
TOs onboard SOFIA have to take into account movements
of the plane through air turbulence, FAA regulations, airspace restrictions, and pre-determined ﬂight plans. "Setups for observations are signiﬁcantly more complicated if
the observatory is in motion," Saurage concludes.
Saurage, like all TOs, relishes a night of successful observing. And unlike guest observers, TOs have
the chance to enjoy these nights regularly - more like
amateurs, although TOs' nightly adventures are largely
planned by someone else. After some much-needed rest
away from their mountaintop or airborne posts, TOs
return to take on the roles of scientists, engineers, and
therapists for another night. ✦
Katherine Kornei is a science writer in Portland, Oregon.
She has a PhD in astronomy and is grateful to the many
telescope operators who helped her collect her thesis data.
Sk yandTelescope.com March 2016

http://www.SkyandTelescope.com

Sky and Telescope - March 2016

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