Sky and Telescope - April 2015 - 50

OBSERVING

Celestial Calendar

A Barely Total Lunar Eclipse

KEITH LISK

On the morning of April 4th, the Moon skims just inside Earth's umbra.
The next total eclipse of the Moon will greet early risers before or during dawn on Saturday morning, April
4th, across much of North America. It will be the third in
the current "tetrad" of four total lunar eclipses coming at
half-year intervals.
In one way, this eclipse will be a lot like the one last
October 8th. Most North Americans will again need to get
up early and look low in the west as dawn brightens. And
again, the farther west you are the better - more so this
time, because the eastern half of the continent misses the
total phase of the eclipse completely.
But in another way it will be diﬀerent. The eclipse will
be just barely total and only for about 10 minutes. You
may even get the impression that it never becomes quite
total at all. The Moon's north-northeastern limb will be so
slightly inside the umbra (the central portion of Earth's
shadow) that it will remain much brighter than the deep
red we can expect across the rest of the Moon's face.
The map below, and the diagram and timetable on
the facing page, tell what to expect at your location and
when. Near the West Coast, you'll see the total phase of
the eclipse happen fairly high in a dark sky long before
sunrise. Skywatchers farther east will ﬁ nd dawn brightening and the Moon sinking low in the west around
totality. For easterners, the Moon sets (and the Sun
rises) during the partial phase before totality begins.
New England misses this one altogether.
If you're in Hawai'i or New Zealand, the eclipse hap-

As it did last October, the
eclipsed Moon on April 4th
will decline in the west as
dawn brightens for most
North Americans. Keith Lisk
of Waverly, Ohio, took 21
shots at 4-minute intervals
during the October eclipse
using an 80-mm lens. He
increased the exposure during the last 8 frames as the
eclipse deepened to totality
(the last 4 frames).

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April 2015 sky & telescope

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50

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For your location, see if the
Moon will set
(or rise) during
any stage of the
eclipse. Because
an eclipsed Moon
is always full, the
Sun rises (or sets)
at almost the same
time on the opposite horizon. This
means that a lunareclipse moonset or
moonrise always
happens in a very
bright sky.
Sky and Telescope - April 2015

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