Sky and Telescope - June 2018 - 20
p MANICOUAGAN The reservoir in summer (top) and winter. This
feature is much larger than others the author has seen from the
air. Often you don't have much choice when it comes to including
foreground wings, but instead of lamenting, think of them as adding immediacy and scale.
Clearwater Lakes: pair
of craters (20 and 30 km
in diameter) just to the
east of Hudson Bay in
Canada. The larger lake
has a ring of islands that
is actually a "peak ring,"
formed when the crater's
central peak collapsed.
Polar ǫights to Asia, or
high-latitude routes to
Europe, may catch it.
Bosumtwi: 10.5 km wide,
Ghana. The closest I've
come was when a taxi
driver taking me to the
Dulles airport was from
a town 30 km from it. He
J U N E 2 018 * SK Y & TELESCOPE
was shocked when I told
him the lake was formed
by an impact!
Roter Kamm: 1-km-wide
shallow structure in
Namibia, overrun by sand
dunes. Flights from the
U.S. to South Africa may
overǫy this (as well as the
beautiful Namib desert).
Gosses Bluff: the 4.5-kmwide ring of hills is
actually not the rim but
rather the eroded core of
the uplifted central rocks
in the crater. West of Alice
Springs in Australia.
p EL'GYGYTGYN A bright sheen reflects off the lake from the Sun,
low in the sky at this latitude of 67° 30´ (top). Clouds stream off the lake
toward the north. A few tens of seconds later, the view has wheeled
around to remove the glint and make the lake's shape a little clearer
against the snowy landscape (above). The lake is slightly off-center from
the ring of hills which marks the crater.
an image-processing program may be helpful (or even using
a camera with an infrared ﬁlter). I try to take a few views.
Sometimes the perspective changes nicely, and, depending on
the Sun-feature-camera geometry, the lighting can change
dramatically. This is especially the case for crater lakes, where
sunglint can be strong, as with El'gygytgyn above.
Some craters that I'd love to see from the air, but haven't
yet, are listed to the left. Maybe you'll have better luck! Paul
Hodge's book Meteorite Craters and Impact Structures of the
Earth is a great travel guide, and there are also several good
resources on impact craters online - the most useful is the
Earth Impact Database at passc.net/EarthImpactDatabase.
¢ RALPH LORENZ is in the planetary exploration group at the
Johns Hopkins Applied Physics Laboratory and worked for 27
years on the international Cassini-Huygens mission to Saturn
and Titan. He is the author of Dune Worlds and the CassiniHuygens Owners' Workshop Manual and does much of his
writing on airplanes.