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1066 6 MARCH 2020 • VOL 367 ISSUE 6482 SCIENCE




nternational megaprojects that cost well
over $1 billion generate most of the ex-
citement in observational astronomy
today: the 39-meter Extremely Large
Telescope under construction in Chile,
for example, or the Thirty Meter Tele-
scope, controversial because of its proposed
location on Mauna Kea, a mountain sacred
to some Native Hawaiians.
But smaller telescopes still do cutting-
edge science as well. And Turkish scientists
are eagerly awaiting the completion of the
new Eastern Anatolia Observatory (DAG), a
4-meter optical and infrared telescope ex-
pected to come online next year. Its main
structure is scheduled to be shipped
to the site, a 3170-meter mountaintop
in northeastern Turkey, this month;
polishing and grinding of the primary
mirror is nearly done.
Despite its modest $34 million
price tag, DAG will be one of Asia’s
largest optical telescopes and Tur-
key’s largest science project. Its de-
velopers hope DAG will make Turkey
a regional astronomy hub and help
nurture its astronomy community.
“We are dreaming of using the instru-
ments on DAG,” says Ozgur Basturk,
an exoplanet scientist at Ankara Uni-
versity. “With a 4-meter telescope, we
can do much better and be more com-
petitive in our field.”
Turkey’s largest telescope today is a
1.5-meter reflector near the city of An-
talya on the Mediterranean coast. The new
facility will sit well above haze and humidity
and far from urban light pollution, and enjoy
288 clear nights per year on average. Its de-
sign and construction, financed by the Turk-
ish government, has involved scientists at
40 universities in the region, along with Eu-
ropean academic and industrial partners.
“It’s not a 40-meter telescope of course,”
says Laurent Jolissaint of the University of
Applied Sciences and Arts of Western Swit-
zerland, the project’s lead optical engineer,
“but we put everything into it. The optics
system is the same essentially as the very
newest systems.” DAG will be run by the
Astrophysics Research and Application Cen-
ter at Atatürk University in Erzurum, a city in
eastern Turkey.
Turkish scientists have little access to the

world’s largest telescopes. The European
Southern Observatory (ESO) in Chile, for in-
stance, prioritizes observing time for projects
led by scientists from the 16 nations that have
helped pay for the facility and contribute to
its €162 million annual budget. “In principle
anyone can apply to use these telescopes, but
the competition is very high, so the research
quality [of your proposals] should be high,”
says astronomer Sinan Alis of Istanbul Uni-
versity. “You have to somehow reach that
level to be able to compete.” In 2010, Turk-
ish astronomers began to lobby their govern-
ment to apply for ESO membership, but they
gave up a few years ago, their hopes dashed
by Turkey’s economic crisis. (Another devel-
oping country, Brazil, dropped its member-

ship bid last year because it could not afford
€270 million in fees over the next decade.)
Unable to make observations themselves,
many Turkish astronomers fall back on archi-
val data from large telescopes that have al-
ready been picked over by other astronomers,
who can take years to release them. Some
Turkish astronomers have struck up collabo-
rations with teams from ESO member coun-
tries, but even then, getting travel funded is
often difficult.
That’s why the new telescope will be such
a boon, Basturk says—for instance, for his
exoplanet research. DAG will allow him
to use one of the standard strategies for
hunting exoplanets: monitoring stars for
a wobbling motion that results from the
gravitational tug of an orbiting planet. But
like other premier telescopes, DAG will also

have a coronagraph, an instrument that
masks bright stars to remove their glare so
that dim planets orbiting them can be im-
aged directly. New technology will enable
the coronagraph to block multiple stars at
the same time, needed to hunt for exoplan-
ets in star systems that, unlike our own,
have two stars or more.
DAG’s large aperture will enable it to
capture light from distant, faint objects like
high redshift galaxies, allowing astronomers
to probe far back into the universe’s history.
That’s important for Alis, who hopes to use
DAG to follow up on data from the Spektr-
RG space observatory, a Russian-German sat-
ellite launched last year to map the x-ray sky
(Science, 14 June 2019, p. 1020). Many objects
can produce x-rays, from black holes
at the centers of galaxies to smaller
black holes or neutron stars consum-
ing mass from a companion star. “We
need to follow up with optical and in-
frared to see what they actually are,”
Alis said.
In an ironic twist, DAG officials
say astronomers from several Eu-
ropean countries have shown in-
terest in Turkey’s new observatory,
despite their access to ESO’s mega-
telescopes, drawn by the location—
there are few others in the Northern
Hemisphere at that longitude—and
affordable observation time. “We
envision DAG as an international
observatory,” says the project’s di-
rector, Cahit Yes ̧ilyaprak of Atatürk
University. “We do not have a prefer-
ence about the origin of the proposals, as
long as the best science cases are proposed
and conducted.”
But the biggest impact will be in Tur-
key itself. Designing the telescope has al-
ready pushed science in other fields. For
instance, dozens of optical, mechanical,
and computer engineers helped design the
telescope’s adaptive optics system, which
will sharpen its images, and its derotator,
a device that keeps the telescope trained on
the same spot as the Earth rotates. “These
are big deals for a developing country,”
Yes ̧ilyaprak says. And the telescope itself
will invigorate Turkish astronomy, Alis says.
“Once we have the telescope, the expertise
will pop up.” j

Umar Farooq is a journalist based in Istanbul.

A new telescope, under construction on a 3170-meter mountaintop
in eastern Turkey, is expected to come online next year.

By Umar Farooq


New telescope promises boon for Turkish science

The 4-meter Eastern Anatolia Observatory aims to become an affordable regional hub

Published by AAAS
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