Total Lunar Eclipse Information

For those of you interested in the total lunar eclipse tomorrow, please see the information provided by my colleague Alex Filippenko:

This coming Sunday night (January 20/21), there will be a total lunar
eclipse (when the Moon goes into Earth’s shadow). Weather permitting,
everyone on Earth’s dark (night) side will be able to see it; this
includes *all* of North and South America. It will also be visible
(closer to horizon) from Hawaii, western Africa, and western Europe.

Totality will last 62 minutes — this isn’t like a total *solar*
eclipse, where you have to be in a very special location and at the
right time down to the minute. Also, unlike the case in a total solar
eclipse, the eclipse will occur at the same time (after adjusting for
time zones) from any location where it is visible. No optical aid is
needed — just use your eyes (though the view through binoculars
should be interesting as well — and you’ll be able to see the
“Beehive” star cluster M44, slightly east of the Moon, in the
constellation Cancer, the Crab).

Here are the  relevant times in California; adjust  for your time zone
if you will be away from  Pacific Standard Time  (PST). (For example,
mid-eclipse  will be  at 12:12 am Eastern Standard Time on Monday,
Jan. 21 — kind of late.)

Partial eclipse begins:   7:34 pm PST Sunday, Jan. 20
Total eclipse begins:     8:41 pm PST
Mid-eclipse:              9:12 pm PST
Total eclipse ends:       9:43 pm PST
Partial eclipse ends:     10:51 pm PST

Prime time (total eclipse) will be 8:41-9:43 pm PST. The Moon will be
in the east, pretty far up from the horizon. (If viewing from Hawaii,
the Moon will be quite low over the eastern horizon, with mid-eclipse
at 7:12 pm HST; try to avoid obstructions like mountains, buildings,
and trees.)

For more information, I highly recommend the following websites:
https://earthsky.org/?p=295245 , and
https://www.skyandtelescope.com/observing/solar-and-lunar-eclipses-in-2019/ .
If you’d like details for your specific location, try
https://www.timeanddate.com/eclipse/lunar/2019-january-21 .
There are lots of other online articles about the eclipse, too.

Also, let me alert you to a handy astronomy/space calendar from the New
York Times that you can download right to your Google or iOS calendars.
They released the 2019 version a few weeks ago:
https://www.nytimes.com/interactive/2019/science/astronomy-space-calendar.html .

Note that this will be the last total lunar eclipse until May 26, 2021
— and that one won’t be visible from most of North America, being
centered on the middle of the Pacific Ocean. So, try not to miss the
one this coming Sunday night!

Wishing you clear skies during the night of January 20/21,

Alex

*****

Additional details:

The Moon doesn’t appear completely dark during a total lunar eclipse
because some sunlight goes through Earth’s atmosphere and is bent
(refracted) toward the Moon, and then it bounces off the Moon back
toward us. But the Moon’s color generally appears some shade of
yellow, orange, or even red because the light that reaches it has been
filtered by Earth’s atmosphere, preferentially getting rid of the
violet, blue, and green colors — just as in the case of the setting
or rising Sun, which looks some shade of yellow, orange, or red,
depending on the amount of particular matter (such as smoke) in the
atmosphere. The totally eclipsed moon is thus often referred to as
the “blood moon.”

Also, the full moon will be a little closer to Earth than average in
its elliptical orbit and therefore look a bit bigger — a “supermoon.”
But this is exaggerated by the press; though the Moon is nearly at
its closest to Earth in its elliptical orbit, a supermoon looks
only slightly bigger (7%) and brighter (14%) than an average full
moon. Also, “supermoons” are pretty common; in fact, this will
actually be the first in a series of three consecutive “supermoons.”

The “wolf moon” part is the least interesting: the first full moon of
the new year is sometimes called the “wolf moon.”

Since all three conditions will be met, this will be a “super blood
wolf moon” — kind of neat, though I personally think that’s going
overboard. (Let’s just call it a total lunar eclipse, okay?)

Given that the Moon will be passing through the top part of Earth’s
shadow, I predict that at the time of mid-totality, the top (north)
part of the Moon will appear brighter and more yellow/orange than the
bottom (south) part of the Moon (darker; orange/red).

Note that during the partial phases, Earth’s shadow on the Moon looks
distinctly curved. This is *always* the case during a lunar eclipse,
and it was one of the many pieces of evidence that the ancients used
to conclude Earth is round, not flat.

(In the above list of times, I didn’t include the “penumbral” eclipse,
when Earth blocks only *part* of the Sun as seen from the Moon; the
full moon will look slightly fainter during the penumbral eclipse, but
this effect is hard to notice.  It begins at 6:36 pm PST and ends at
11:48 pm PST.)

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