Lunar Eclipse to be Visible on Sunday Night

Media contact: Jay Pasachoff at [email protected] or 617 285 6351

WILLIAMSTOWN, Mass., September 25, 2015—Observers in the eastern United States will be treated to a pleasant spectacle on Sunday night, September 27—a total eclipse of the Moon. Anyone looking eastward toward the Moon on that night can watch a show unfurl gradually, as the Moon is first covered and then uncovered by our Earth’s shadow.

Starting at 9:07 p.m., the Earth’s shadow will begin to darken one edge of the Moon. Over the next hour or so, more and more of the Moon will be in shadow. Between 10:11 and 11:23 p.m., the Moon will be entirely in the Earth’s broad shadow. During that time, the Moon will remain faintly visible, since a little sunlight will be bent around the Earth by our atmosphere.  Since the blue light will be preferentially scattered out to make blue skies, mainly some faint reddish light will hit the Moon. The shadow will be darkest when the Moon is deepest inside the eclipse zone, close to 10:47 p.m. Between 11:23 p.m. and 12:27 a.m., the Moon will gradually emerge from the Earth’s shadow.

Williams College Prof. Jay Pasachoff, Field Memorial Professor of Astronomy, says that “a lunar eclipse is fun to watch, and weather predictions are for clear skies. It isn’t dramatic but looking up at the Moon every few minutes or perhaps every 15 minutes as the night wears on can be fun, and should be encouraged to enjoy the view. An eclipse of the Moon is merely an especially well-aligned full Moon, when the Moon rises in the east as the Sun sets in the west, and the Earth gets in the way of the sunlight.”

Pasachoff adds that “Misleadingly, some articles are calling it a ‘blood moon,’ which is just superstition and astrology and has nothing to do with what will actually happen. Merely because the Moon will look faintly reddish doesn’t justify using the word ‘blood.’ Also, the Moon will be closer than average to the Earth and therefore a little larger in the sky, about 14% from that of a previous lunar eclipse, but that small difference won’t be noticeable to casual observers.”


Founded in 1793, Williams College is the second-oldest institution of higher learning in Massachusetts. The college’s 2,000 students are taught by a faculty noted for the quality of their teaching and research, and the achievement of academic goals includes active participation of students with faculty in their research. Students’ educational experience is enriched by the residential campus environment in Williamstown, Mass., which provides a host of opportunities for interaction with one another and with faculty beyond the classroom. Admission decisions on U.S. applicants are made regardless of a student’s financial ability, and the college provides grants and other assistance to meet the demonstrated needs of all who are admitted.