There are only a few days to go. I hope you have tested your eclipse glasses and know they are safe. I hope you’re prepared to be in the best location for you to enjoy this experience. I hope you’re ready for an amazing Monday.
Ken has a few last words to inspire and guide your eclipse experience. Read ahead and think about all the things that might help Monday go just a little smoother for all.
Take it away Ken…
Let me begin with an admonition:
If you can get into the path of totality-do it! Take the day off! A total eclipse is a life-changing event, and you want to see it, hear it, and feel it. Get out there if it can be done. Bear this in mind: if you go, make sure you’ve got gas, food, and water for after the eclipse is over. You must be prepared for the resulting traffic jams. I’ll be in the Republic of Texas, and my daughter’s partner, who is from there, will be navigating the back roads back to our hotel in San Antonio. We will still be prepared for a long drive back.
Back in school, somewhere, you were taught about Solar and Lunar eclipses. You were also taught about the phases of the moon. Hopefully, you were taught that eclipses deal with shadows, and phases are determined by the apparent angle between the Earth, Moon, and Sun. We see the run of moon phases every month. For example, today, the Moon is a thin crescent in this morning’s sky, low in the Eastern sky soon before dawn. The angle between the moon and Sun is about 35 degrees on Friday morning. Monday, that angle approaches zero degrees. But angles are also crucial in the examination of eclipse geometry. In order for eclipses to occur, a precise alignment of Earth, Moon, and Sun must exist. The apparent angle between the Earth, Moon, and Sun in a total solar eclipse is 0 degrees.
Additionally, the Moon must be on the node of its orbit around Earth. This is the primary reason that we don’t see eclipses every month. Most of the time, the Moon’s orbital tilt (5 degrees relative to Earth’s orbital plane) means that usually, the Moon’s shadow is projected into space above or below Earth during the new moon. The node is that point where the Moon’s orbital plane intersects with Earth’s.
Fortunately we were treated to a partial solar eclipse in October. This setup is very rare, and we won’t see such a thing again in our lifetimes!
Saturday, October 14th featured a special kind of eclipse called an annular eclipse. The next eclipse after that is a total eclipse, occurring on Monday, April 8th. For many school districts, as in the Public Schools of Robeson County, this is the Monday following Spring Break, so students will be in school during this eclipse, and dismissing to go home. Permission slips have been sent home for all PSRC students to participate in any outdoor activities associated with the eclipse. Unfortunately, the best part of the eclipse happens when students are transiting home from school.
So, what happens when? Shortly before 2 PM EDT, the eclipse begins in Robeson County. At 3:14 PM, we reach a maximum eclipse, which is roughly 80 percent of the Sun covered by the Moon. By 4:30 PM, the eclipse has ended. The weather outlook for Monday the 8th is promising, but if it’s cloudy, you can view one of the eclipse live streams below.
For the benefit of those wishing to watch the total eclipse from here, there are two live video streams I recommend:
- NASA’s official livestream event: https://www.youtube.com/watch?v=2MJY_ptQW1o
- Exploratorium’s livestream event:
https://www.exploratorium.edu/eclipse/livestream scroll down the page.
Solar eclipses are a rare event. Our next opportunity for a partial eclipse here in NC will be in 2045.
This eclipse is literally twice as long as the last total eclipse here in NC, back in 2017. Totality for that one was 2 minutes and 3 seconds. In parts of central Texas, totality lasts for 4 minutes, 25 seconds. Why is this so different? The geometry of the Moon’s orbit around Earth is the culprit. The moon changes its distance from Earth as it’s orbit is an ellipse, not a circle. You can get a feel for this by doing a simple activity. Hold your thumb at arm’s length. Hold your thumb straight up, without tensing your muscles at all. Your thumbnail represents the moon, and in this position, the moon is at its “average” distance from Earth.
Relax your Thumb against your hand-this was the setup for last October’s annular eclipse. Bringing your thumb slightly closer, between your palm, and average distance, that was the moon’s distance for the 2017 eclipse. Now, flex your thumb towards your open eye-without moving your locked elbow. That’s this edition of the eclipse. You should be able to see that your thumbnail is slightly larger, just as the moon will be April 8th.
A third grader asked me: “during the eclipse, can the Sun and Moon collide? No, they’re separated by some 92 million miles, so no worries. You can do a simple activity involving both hands, and one open eye to demonstrate this impossibility for yourself. Hold your right pinkie about 1 inch from your nose. Lock your elbow in that position. Hold your left thumb at arm’s length-again, locking your elbow. Now, looking through one eye, move the pinkie near your nose so it covers your thumb. Assuming you don’t cheat and move elbows, try to hit the thumb with the pinkie. Normally, that is impossible to do. Likewise for the Moon and Sun.
A partial solar eclipse creates some safety challenges. First, all steps in the eclipse must be observed without looking directly at the Sun. There are several techniques that you can employ here involving pinhole projection:
(1) Get two 3×5 cards
(2) Poke a small pencil hole in one of them
(3)Holding the “holey” card closer to the Sun, project the image into the second card.
Alternatively, you can use a colander with small holes to project the image onto a piece of paper, or the sidewalk. Obviously, if you still have eclipse glasses, you can use those. Remember to check them for “light leaks” by holding them up to a patch of daytime sky without the Sun in it. If you see anything, discard the glasses, as they are unsafe.
Whatever you choose to do: DO NOT look directly at the Sun without proper eclipse glasses. You can damage your eyes.
A final word for those holding eclipse events: remember to have many different activities available for your eclipse event attendees. You should never depend solely on good weather for an event like this!
Coming up: The Last Eclipse Blog – Parlaying this event for other events in the future.
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Ken Brandt directs the Robeson Planetarium and Science Center for the Public Schools of Robeson County. He is a volunteer in NASA’s Solar System Ambassador Program. He is also a member of the 3rd cohort of NC Space Grant Ambassadors, and an Ambassador for the Mars Society. Ken is also Co-Chair of the International Planetarium Society’s Education Committee.