Bay Area Skeptics

The San Francisco Bay Area's skeptical organization since 1982

Eclipsing with the SciSchmooze 19.1.20

by Herb Masters

Hi Science Celebrators! 
Please excuse this very early edition of the SciSchmooze.  I am hoping that this helps you  get ready for Sunday evening’s big event.  Let’s hope for clear skies but there will be alternatives for you to enjoy the eclipse even if the skies are not clear. 

I got an email from Alex Filippenko with a great compilation of info that will help you and your friends and family enjoy and understand what is going on.  In case you don’t know, Alex is an astrophysicist at UC Berkeley who has been involved in major discoveries about our universe.  You really do need to see and hear him speak.  Oh yea, you can…  Black Holes, Exploding Stars, and the Runaway Universe: A Life in Science is this coming Wed 1.23 at Foothill College.  Go see, hear, learn, and celebrate!

Back to this Sunday…  Here’s what Alex shared with all us…

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, but this Monday is a holiday for most people!)

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: , and 
If you’d like details for your specific location, try .  There are lots of other online articles about the eclipse, too. 

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,

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.)


Check out the Bay Area Science Calendar for the full listing of Eclipse events.  If you can’t get out from under the clouds or your roof, there will be many on line programs about the eclipse as well.  Our very own explOratorium will be webcasting Live Lunar Eclipse Coverage from 7:30 to 10:30. 
It isn’t really a coincidence but there will be 5 King Tide programs from Saturday through Monday as well.  Try searching for King Tide on our calendar.  There’s no program but check out Bair Island in Redwood City for a great experience of the King Tide.  There is a 16.2′ difference between high and low tide on Sunday!  Check it out for awhile, go get some breakfast, go see the tide, and then check out something else in the area.  Hiller Museum comes to mind, then go back and see more of the changes. 
So there are plenty of other things to learn next week as well.  (Starting with Monday!)

  1. January LASER event   7:00 Tues  San Francisco
  2. Madagasikara: The Real Madagascar Film Screening  6:30 Wed  San Francisco
  3. Resolving the Local Universe with the Hubble and James Webb Space Telescopes 7:30 Sat  Oakland

It is a bit far to go but the Natural History Museum in Pacific Grove is a gem.  Make a day trip of it and check out Science Saturday: Amazing Migrations  Sat 1.26. 

It’s a week full of learning opportunity.  I hope you can take advantage of some of it.

I hope that the politics in Washington DC get resolved soon.  Certainly there are a lot of great people who work in many areas of our government that are experiencing real hardship; any news report is documenting them.  The deeper damage being done to our institutions will take a while to figure out.  Here are two articles on the impact on science…  As Government Shutdown Drags On, Science Sputters and Science and the Federal Shutdown.

Here’s a bit of The Moon’s Magical Mythology just for fun!

Have a great Martin Luther King day.  (Would that be a Martin Luther King Tide Day?)

herb masters

“Science investigates; religion interprets. Science gives man knowledge which is power; religion gives man wisdom which is control. Science deals mainly with facts; religion deals mainly with values. The two are not rivals. They are complementary.”  Martin Luther King, Jr.
In ‘A Tough Mind and a Tender Heart’, Strength To Love (1963)

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