Recorded on April 15th, this total
lunar eclipse sequence looks south down icy Waterton Lake from the
Lakes National Park in Alberta, Canada, planet Earth.
The most distant horizon includes peaks in
Glacier National Park,
An exposure every 10 minutes captured the Moon's position and
eclipse phase, as it arced, left to right, above the rugged skyline
and Waterton town lights.
In fact, the sequence effectively measures the roughly 80 minute
of the total phase of the
Around 270 BC, the Greek astronomer
also measured the duration of lunar eclipses - though probably without
the benefit of digital clocks and cameras.
using geometry, he
devised a simple and impressively accurate way to calculate
the Moon's distance, in terms of the radius of planet Earth,
from the eclipse duration.
This modern eclipse sequence also tracks the successive positions of Mars,
above and right of the Moon, bright star Spica next to the reddened
lunar disk, and Saturn to the left and below.
Yuichi Takasaka /