This is the Classical Astronomy Update, an email newsletter especially
for Christian homeschool families (though everyone is welcome!) Please feel free to share this with any interested friends.
While the earth remaineth, seedtime and harvest, and cold and heat, and summer and winter, and day and night shall not cease. -- Genesis 8:22 IN THIS UPDATE The Autmnal Equinox Hello Friends, The days have grown quite short lately. Don't know about you but the summer of 2023 went by way too quick! Seems like it just got started and now it's over already! But I love the fall weather -- the nip in the Ohio air, the golden afternoons, the dramatic
sunsets, and the nice cool sleeping weather at night. The annual cycle of the seasons is a joy and a blessing. My seasonal experience has been enhanced since beginning to learn Classical Astronomy 35
years ago. My own appreciation of the passing seasons -- seedtime and harvest, and cold and heat, and summer and winter, and day and night -- is improved by understanding the celestial causes of the seasons, how the annual variations in the position of the Sun result in the annual variations in climate, here in Ohio and around the globe. My thanks to you, friendly reader, for following the Classical Astronomy Update, and for seeking to learn the wonderful celestial cycles that can be observed above eye
level, which most people neither notice or are even aware. Spectacular Green Flash Over Lake
Erie! As reported in a recent newsletter, I have had a hot streak in 2022 and 2023 of sighting the elusive green flash over Lake Erie. But on August 31, I saw the most spectacular apparition of this rare phenomenon. It was a perfect crystal day, on the cool side, and the Sun was setting VERY bright. This resulted in a DAZZLING green flash, the 10th I've seen in 30 years from Edgewater Park in Cleveland. The green flash is a rare optical phenomenon, mostly observed in the tropics, but also visible over the Great Lakes (as I can attest). It’s a type of atmospheric mirage effect. Bottom line, all the sunlight rays of the other colors in the rainbow set first, leaving only the green rays to set last, so that the final tiny speck of Sun becomes bright green in the brief instant
before setting. It’s very quick and you really need to pay attention, it’s easy to miss if you’re not ready for it. I’d seen the green flash 9 times previously from this location, once before in 2023, 4 times in 2022 and 4 times
going back 20 years, with one of those times during the Venus transit of 2012. Having seen it so many times recently I’m getting good at recognizing the atmospheric circumstances that precede the green flash. You need a really
clear day with a bright yellowish or light orange Sun. Due to refraction, the last bit of the setting Sun looks like an oval shape partially extending below the horizon. That oval takes on a greenish tinge around the edges as it shrinks, as the Sun dips below the horizon, becoming more and more greenish until the last little speck turns completely green for a split second, and then it vanishes. This 10th time at 8:01 PM on Thursday, August 31, 2023 was the most spectacular I’ve ever seen. The Sun was SO BRIGHT, it was impossible to watch as it set, only for the last little bit. I stood on a nearby picnic table and squatted down, and then did the old trick of standing up as the Sun sets to “see a second
sunset.” (This would require a separate explanation.) Anyway, I knew from experience to stand up slowly, to prolong the image of the last speck of the setting Sun. The green flash was ABSOLUTELY DAZZING, as bright as a green laser pointer, that same minty color, looking like a green Venus on the horizon. (The following image is my "artist's conception" of what I saw, a pic snapped shortly after sunset with the green image added.) ECLIPSE WEBSITE! The animated videos to help explain about the causes of eclipses and what you can expect to see during a total solar
eclipse. Though they are locally focused, the same principles are applicable to other locations. - Eclipses Explained -- An animated basic primer on the differences between partial, annular and total solar eclipses.
- The Eclipse Experience -- An animated walkthrough of a total solar eclipse, including
visual depictions of all the phenomena that one might expect to see.
- Eclipse Misconceptions -- A lighthearted look at five of the common “urban legends” that circulate about eclipses. MUST SEE!!! MUST
SHARE! FUNNY!
- Eclipse Over Ohio - An animated step-by-step depiction of the path of totality across the State of Ohio, including detailed explanations of why eclipse viewing differs with location in the Buckeye
State (partial vs. total, different durations of totality across the path). This video is important to help Ohioans understand why Akron, Cleveland, Dayton and Toledo will experience totality and why Canton, Cincinnati, Columbus and Youngstown will not, and why everyone should get onto the path, the further, the longer.
I especially encourage everyone to hurry up and order Eclipse Shades solar
viewers. The annular eclipse of Saturday, October 14, 2023 is coming up soon! Keep them handy for the total solar eclipse of Monday, April 8, 2024. There is always a high demand for Eclipse Shades and the sellers always run out before eclipse time. Check out our new online Eclipse Store. We currently
offer Cleveland-branded Shades, Ohio-branded Shades, and standard non-branded Shades if you're not from the Buckeye State. Our Classical Astronomy site is still hobbled and and we cannot directly sell our Signs & Seasons homeschool astronomy curriculum at this time. But the S&S pages on the site are still active and include links to our resellers where you can order the curriculum at a discounted price. For more information about topics from Classical Astronomy discussed in this newsletter, please check out a homeschool astronomy curriculum (but popular with adult readers too!) Visit our archive of previous editions of the Classical Astronomy Update newsletters, going back to 2007. ***** The Autumnal Equinox I was outside the other day around sunrise to hang the American flag on our flagpole. I looked over and saw the Sun rising very much to the east, no longer in the far north as it had been since May. This is a sure "sign" in the heavens of the end of summer and the approach of fall. A recent edition of this newsletter explained about the vernal equinox back in March. Now that summer is nearly spent, the time is soon coming for the autumnal equinox. So this newsletter will add some more facts about the equinoxes. The autumnal equinox is both a place and a time. It is a location on the celestial sphere where the circle of the celestial equator intersects with the circle of the ecliptic. (For detailed explanations of these concepts, check out our Signs & Seasons curriculum. The autumnal equinox is better known in the public mind as the day of the year when the Sun passes the point of the autumnal equinox in the sky. The ecliptic is the apparent annual path of the Sun against the background constellations that results from the Earth's orbital motion, the changing line-of-sight of the Sun's position among the stars. The celestial equator represents the midpoint between the north and south celestial poles, around which the
celestial sphere appears to rotate with each 24 hour rotation of the Earth. Autumn begins on the precise moment when the Sun is centered on the celestial equator, which, in 2023, is 2:50 AM EDT on
Saturday, September 23. The celestial equator crosses the horizon at due east and due west. So on the day of the autumnal equinox, the Sun is seen rising and setting at these cardinal points. And since the celestial equator divides the celestial sphere in half, the length of the day and the night are equal, 12 hours of daylight and 12 hours of nighttime. The seasonal cycle of The Year occurs because the Earth's axis is slightly tilted to the plane of the ecliptic, which is the plane of the Earth's orbit around the Sun. As the Earth goes around the Sun, the axis remains pointed in the same direction.
As a result, the North Pole on the Earth is inclined toward the Sun on the summer solstice, and inclined away from the Sun on the winter solstice. On the spring and autumn equinoxes, the plane of the Earth's axis is perpendicular to the rays of the Sun's light. (The image below is taken from our Signs & Seasons curriculum. ) At all times, the Earth's axis is pointed in the general direction of the star Polaris, the North Star. So as the Earth rotates annually around the Sun, the direction of the axis remains unchanged, always pointing at the North Star. (The image below is
also taken from our Signs & Seasons curriculum.) People are often confused by this, wondering why the direction of the axis does not change with the Earth's orbital motion. This is because of inertia, as explained by Isaac Newton. The direction of the Earth's axis can only change if there is a force
acting upon the Earth that would redirect the axis. The fact is, the Moon's gravity exerts such a force upon the Earth. This force results in precession, in which the Earth's axis slowly wobbles over span of thousands of years. Because of precession, Polaris will one day no longer be the North Star. Precession also causes all the constellations to change positions. So the constellations that currently host the solstices and equinoxes will be one day be moved
away, and new constellations will move in to host these seasonal cardinal points. This same inertia of the Earth's axis also applies to the elements of the Earth's orbit, and also the Moon's orbit. While the Moon's
gravity causes precession of the Earth's axis, the Earth's gravity produces an "equal and opposite reaction" upon the Moon, shifting the inclined plane of the Moon's orbit in an 18.6 year cycle. The combined gravity of the Earth and Sun also cause a small shift in the Moon's perigee, or closest point in its orbit to the Earth, which shifts in an 8.85 year cycle. For the most part, the positions of the Moon's orbital elements remains fairly consistent over the span of months. I'm explaing all this because it is relevant to the subject of the next newsletter, which will be out (hopefully) in a week or so. This upcoming newsletter will explain the orbital circumstances that
produce the "Blue Supermoon" in August, 2023 followed by the annular eclipse in October, 2023, and how that pertains to the total solar eclipse coming up in April, 2024. Anyway, as seen from a
celestial "God's eye" perspective, the Sun's light shines equally on all latitudes of the globe at the equinox. Every location in the world experiences 12 hours of daylight and 12 hours of nighttime. When the Sun is crossing the celestial equator, it is directly overhead in the sky above the terrestrial Equator, as seen from the equartorial nations of South America and Africa. Conversely, the Sun's parallel rays graze the globe at the North Pole and the South Pole. As seen from those frozen lands, the Sun appears on the horizon. The autumnal equinox marks the end of the long six month polar "day" at the North Pole but the beginning of the six month Antarctic "day" at
the South Pole. This might make a good subject for a future Classical Astronomy Update, maybe next March. I really miss the "good old days" when the readers used to send emails asking astronomy questions. Some of the best newsletters came from those emails. So please drop a line sometime of if you are wondering about any Classical Astronomy
topics. Till next time, God bless and clear skies, - jay The Ryan Family Cleveland, Ohio, USA When I consider thy heavens, the work of thy fingers, the moon and the stars, which thou hast ordained, what is man that thou art mindful of him? and the son of man, that thou visitest him? - Psalm 8:3-4, a Psalm of David
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