If you've seen one eclipse, you've seen...
October 12, 2022 12:43 PM Subscribe
Calculating when eclipses will happen using "the sort of mathematics that you learn in grade school and an understanding of what we in music would call harmony" along with a vertical stick, a place to sit, and a reasonable timepiece. If you prefer text, NASA explains the Saros in Solar Eclipse Periodicity.
The Time and Date website, amongst other things for us time-obsessed people, has a section on eclipses.
posted by Wordshore at 2:36 PM on October 12, 2022 [2 favorites]
posted by Wordshore at 2:36 PM on October 12, 2022 [2 favorites]
like what am I actually looking for, and then what do I do with them?
As far as I can tell, it's about measuring the time between the moon being "the same as it was last time", in three different ways.
- new moon to new moon - I'm guessing you could measure full moon to full moon instead, since that seems simpler? And you'd do it over the course of a few months to get that half-day bit in there?
- perigee to perigee - you'd need to measure the apparent size of the moon and see when it returns to the exact size it was. I've done this (as part of measuring the distance to the moon, not for eclipses) by taping a small strip of paper to the end of a measuring tape and recording how far I had to push it from my eye to exactly cover the moon, but I have no idea if that would be accurate enough for this.
- node to node - I'm guessing you'd want to measure the moon's angle up from where the sun was that day, and then time when it returns to that exact angle, as opposed to measuring its angle compared to the North Star or horizon.
I'd be happy for any corrections or expansions.
posted by clawsoon at 4:14 PM on October 12, 2022 [2 favorites]
As far as I can tell, it's about measuring the time between the moon being "the same as it was last time", in three different ways.
- new moon to new moon - I'm guessing you could measure full moon to full moon instead, since that seems simpler? And you'd do it over the course of a few months to get that half-day bit in there?
- perigee to perigee - you'd need to measure the apparent size of the moon and see when it returns to the exact size it was. I've done this (as part of measuring the distance to the moon, not for eclipses) by taping a small strip of paper to the end of a measuring tape and recording how far I had to push it from my eye to exactly cover the moon, but I have no idea if that would be accurate enough for this.
- node to node - I'm guessing you'd want to measure the moon's angle up from where the sun was that day, and then time when it returns to that exact angle, as opposed to measuring its angle compared to the North Star or horizon.
I'd be happy for any corrections or expansions.
posted by clawsoon at 4:14 PM on October 12, 2022 [2 favorites]
Thanks to this, I discovered April 8 2024 will have a total solar eclipse that passes right over Toronto (and a few other places, I'm sure).
posted by seanmpuckett at 5:45 PM on October 12, 2022 [1 favorite]
posted by seanmpuckett at 5:45 PM on October 12, 2022 [1 favorite]
Thanks to this, I discovered April 8 2024 will have a total solar eclipse that passes right over Toronto (and a few other places, I'm sure).
Does that mean there was one in 1970?
posted by clawsoon at 10:26 PM on October 12, 2022
Does that mean there was one in 1970?
posted by clawsoon at 10:26 PM on October 12, 2022
@clawsoon: Yup.
http://xjubier.free.fr/en/site_pages/solar_eclipses/TSE_1970_GoogleMapFull.html
posted by ptfe at 4:37 AM on October 13, 2022
http://xjubier.free.fr/en/site_pages/solar_eclipses/TSE_1970_GoogleMapFull.html
posted by ptfe at 4:37 AM on October 13, 2022
http://xjubier.free.fr/en/site_pages/solar_eclipses/TSE_1970_GoogleMapFull.html
Is it too late to restart some ancient priesthood and milk some cash out of this?
posted by clawsoon at 4:49 AM on October 13, 2022
Is it too late to restart some ancient priesthood and milk some cash out of this?
posted by clawsoon at 4:49 AM on October 13, 2022
Huh. I remember reading that eclipse prediction was a big deal in the ancient world (China especially, but unsurprisingly lots of places, since eclipses, especially full solar eclipses, are pretty potent phenomena). Obviously eclipse prediction today is very straightforward, with our full model of the solar system and ability to basically determine with arbitrary accuracy the position of every planet and moon at any time, but I found myself wondering how the hell people millennia ago with mostly incorrect models of the solar system and with much, much cruder calculation technology did it. This is pretty illuminating, because it does seem like you can do a pretty good job of predicting eclipses with simple arithmetic and some observation, both of which would have been within the abilities of a Shang Dynasty astronomer.
posted by jackbishop at 6:42 AM on October 13, 2022
posted by jackbishop at 6:42 AM on October 13, 2022
Does that mean there was one in 1970?
Yes, and that might be the one referred to in Carly Simon's song "You're So Vain" ("Then you flew your Learjet up to Nova Scotia/To see the total eclipse of the sun") - although Nova Scotia actually had total eclipses in both 1970 and 1972 so it's not really clear.
posted by madcaptenor at 8:13 AM on October 13, 2022
Yes, and that might be the one referred to in Carly Simon's song "You're So Vain" ("Then you flew your Learjet up to Nova Scotia/To see the total eclipse of the sun") - although Nova Scotia actually had total eclipses in both 1970 and 1972 so it's not really clear.
posted by madcaptenor at 8:13 AM on October 13, 2022
Andrew Weil wrote a book about both drug and non-drug induced consciousness altering experiences entitled The Marriage of the Sun and Moon. The title refers to the most profound of the non-drug induced: total solar eclipses.
Kate Russo wrote a book on the topic: Total Addiction: The Life of an Eclipse Chaser.
See also Eclipse Chasers KQED Quest
And...
Dancing in the Cosmic Sweet Spot: Total Solar Eclipse Gatherings
So, you see If you've seen one eclipse, you... have only just begun.
posted by y2karl at 8:55 AM on October 13, 2022
Kate Russo wrote a book on the topic: Total Addiction: The Life of an Eclipse Chaser.
See also Eclipse Chasers KQED Quest
And...
Dancing in the Cosmic Sweet Spot: Total Solar Eclipse Gatherings
So, you see If you've seen one eclipse, you... have only just begun.
posted by y2karl at 8:55 AM on October 13, 2022
I have a friend in Seattle who makes it a point to go to Gasworks park during any eclipse to blast out "Total Eclipse of the Heart" to which many, many people sing along. It's a ritual.
posted by seanmpuckett at 9:20 AM on October 13, 2022
posted by seanmpuckett at 9:20 AM on October 13, 2022
I have a friend in Seattle who makes it a point to go to Gasworks park during any eclipse to blast out "Total Eclipse of the Heart" to which many, many people sing along.
Does your friend also do it for partial eclipses?
posted by clawsoon at 10:24 AM on October 13, 2022
Does your friend also do it for partial eclipses?
posted by clawsoon at 10:24 AM on October 13, 2022
A bit of trivia about the April 8th 2024 eclipse: "Carbondale, Illinois enjoys it’s second total solar eclipse just 7 years after the August 21, 2017 eclipse. "
posted by 922257033c4a0f3cecdbd819a46d626999d1af4a at 5:28 PM on October 13, 2022
posted by 922257033c4a0f3cecdbd819a46d626999d1af4a at 5:28 PM on October 13, 2022
clawsoon: I think you'd dig the book Astronomical Algorithms by Jean Meeus. It has all the mathematical reasoning of celestial body motion. Sadly, the other astronomical thing about this book is its price.
posted by scruss at 6:09 PM on October 14, 2022
posted by scruss at 6:09 PM on October 14, 2022
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I would love to read more about the simple amateur astronomy methods he talks about at the beginning.
like what am I actually looking for, and then what do I do with them?
posted by ArgentCorvid at 1:55 PM on October 12, 2022 [1 favorite]