Near its northernmost declination,
tonight's Full Moon will
be a special one,
arcing high in northern hemisphere skies.
But a Full Moon won't occur on this
calendar date for another 19 years, a period known as the
lunar Metonic cycle.
September 15th's lunar phase and date were notable too,
marking the return of a gibbous Moon rising over
the High Sierra mountains.
That scene was captured in
photograph Autumn Moon from Glacier Point,
Yosemite National Park.
Earlier this year,
Texas State University physicists Donald Olson,
Russell Doescher and students were able to pinpoint the location
and (formerly uncertain) date the original
Ansel Adams photo was
taken - September 15, 1948.
Accordingly, their astronomical detective work predicted that
the lunar alignment and waxing gibbous phase would be repeated on
Thursday, September 15, 2005, exactly three 19-year Metonic
On that day, about 300 photographers gathered at Glacier Point to record
Adams' Autumn Moon encore.