Could you explain, simply, what
happens during a lunar eclipse?
During a lunar eclipse, the Moon travels through the Earth’s
shadow. During a total lunar eclipse, an astronaut standing on
the Moon would see no part of the Sun. They would see only a
sliver of reddish light scattered around the edges of the Earth by
our atmosphere. They would be seeing light from all of the
sunrises and sunsets on the Earth at the same time. Therefore
the Moon takes on a copper or reddish hue for the same reason
that sunsets are red.
It begins at 9:06 p.m. and ends at
12:28 a.m., correct?
Technically the Moon also travels through the
Earth’s penumbral shadow as well, but this is
rarely visible at all, so I’ve ignored it. An
astronaut standing in the penumbral shadow
would see only part of the Sun blocked by the
Earth. The penumbra produces such a gentle
shading that I usually ignore it entirely.
It begins at 9:06 p.m. and ends at
12:28 a.m., correct?
The above times are correct for the umbral shadow,
beginning on Sunday night and ending the following
morning. Fred Espenak at NASA has a pdf that
differs by a minute or so from the times I provided:
http://eclipse.gsfc.nasa.gov/LEplot/LEplot2001/LE2
015Sep28T.pdf NASA may use a slightly different
model for the Earth’s shadow. In the NASA pdf, you
have to subtract 4 hours to get EDT.
When was the last lunar eclipse and why
will the next one not occur until 2019?
If the plane Moon’s orbit were fixed in space then we might
expect that every six months we’d have either a lunar or solar
eclipse. Because the Earth isn’t a perfect sphere, and
gravitational tugs by the Sun, the plane of the Moon’s orbit
precesses like a top, making a complete rotation in 18.6
years.
If you want to predict eclipses more than a few decades into
the future or the past, then the Moon’s motion becomes very
complicated. Sir Isaac Newton claimed that the only time his
head ever hurt was when he was trying to make sense of the
Moon’s apparent motion. A relatively complete theory of the
Moon’s motion had to wait for the 20th century.
I’ve seen this being called a “supermoon lunar
eclipse”…is that correct and what is the difference?
Ref: http://eclipse.gsfc.nasa.gov/SEhelp/moonorbit.html
Perigee: “closest to Earth”
Apogee: “farthest from Earth”
The Moon’s orbit is nearly, but not exactly, circular. The average
difference in apogee/perigee is about 11%, that is, the Moon is
about 11% closer at perigee than apogee on average. The
difference between 14-Sept’s apogee and 27-Sept’s perigee is
12%. So the eclipse “super-Moon” is something you’ll never notice
unless measured with some technology.
Apogee:
Perigee:
14 Sep 2015 7:25
27 Sep 2015 21:48
(406463.3 km)
(356876.4 km)
What might viewers at the observatory see?
Beginning at 9:06 PM EDT, the Moon will begin to enter the Earth’s shadow. The Moon
will completely exit the shadow at 12:28 AM, on Monday morning.
Moon leaving the Earth’s shadow
2007-03-03 St. Paul, Minnesota
7:22 PM CDT Nikon S4 “Point’n’Shoot” Camera