Sky and Telescope - April 2015 - 62

Airborne Astronomy

Science From SOFIA
SOFIA's telescope is modest compared to the giants
at modern ground-based observatories, but those are
limited to viewing only in a few near-infrared wavelengths due to atmospheric absorption. Meanwhile,
infrared-sensing space telescopes such as Spitzer and
Herschel, having run out of cryogenic coolant, can no
longer record the longer-wavelength radiation from very
cold cosmic sources.
That leaves SOFIA in a unique position to collect
images and spectra throughout the infrared spectrum:
at wavelengths from 1 to 1600 microns. Since the plane's
"ﬁrst light" ﬂight in mid-2010, astronomers have used
it to probe scores of targets. U.S.-funded research takes
up 80% of the ﬂight hours, while German astronomers
get 20%. SOFIA's instruments are typically used in rotation, each getting bolted to the telescope for several
ﬂights before mechanics switch it out for another.
Eight reports of early science results from the ﬂying
observatory were showcased in a special 2012 issue
of Astrophysical Journal Letters. More recently, both
FORCAST and FLITECAM were used to record Supernova 2014J, and over the next year astronomers will use
SOFIA to study a wide range of planetary atmospheres,
interstellar clouds, protoplanetary disks, and ejected
matter from novae and supernovae.
SN 2014J

2014

too late, and the cobalt will have spread out too far and
become too dim. "We're hoping it's the right time," he
says. The ﬂight plan calls for SOFIA's telescope to stare at
SN 2014J for nearly 3 hours.
Take-oﬀ is scheduled for 6:37 p.m. I settle into one of
the vintage ﬁrst-class seats as the Sun lingers over the
western horizon. But murmuring in the cabin signals
that something is amiss. Soon ﬂight director Randy
Grashuis gathers everyone and delivers the bad news:
there's an errant ﬂap sensor in the cockpit display. The
ﬂap itself is OK, but the sensor is dead. Unless a replacement is found fast, tonight's ﬂight will be scrubbed.
"Not again!" I groan.
My eﬀorts to ride SOFIA go back to 2011, when I'd
watched three chances come and go. Too much rain foiled
the ﬁrst attempt, and a schedule mismatch scuttled the
second. For the third try, I headed to SOFIA's home base,
NASA's Dryden Aircraft Operations Facility in Palmdale, California, and completed all the requisite preﬂight
training for that evening's ﬂight. Then it snowed - in
the Mojave Desert! The ﬂight was canceled because DAOF,
understandably, has no snowplows.
62

April 2015 sky & telescope

Upper left: The heart of the Cigar Galaxy, M82, was an early
target for SOFIA and its FORCAST camera at wavelengths of
20, 32, and 37 microns. Left: The near-infrared view of M82 -
and Supernova 2014J - captured by the FLITECAM instrument.

S&T: J. KELLY BEATTY

NASA / FORCAST SCIENCE TEAM / FLITECAM SCIENCE TEAM (2)

2010

The author poses with the business end of SOFIA's telescope: the
bulkhead, Cornell's half-ton FORCAST camera/spectrometer, and
a counterweight at top center containing racks of electronics.

Sky and Telescope - April 2015

Table of Contents for the Digital Edition of Sky and Telescope - April 2015