Starship Asterisk*

Moon's Shadow over Lake Magog

Explanation: Captured in this snapshot, the shadow of the Moon came to Lake Magog, Quebec, North America, planet Earth on April 8. For the lakeside eclipse chasers, the much anticipated total solar eclipse was spectacle to behold in briefly dark, but clear skies. Of course Lake Magog was one of the last places to be visited by the Moon's shadow. The narrow path of totality for the 2024 total solar eclipse swept from Mexico's Pacific Coast north and eastward through the US and Cananda. But a partial eclipse was visible across the entire North American continent.

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And that must be Venus!

Couldn't understand one basic aspect. Why the eclipse is seen starting from west coast in US to east coast in US.. Apparent motion of moon from east to waste should be faster than Sun's apparent motion from east to west.. So I was imagining it'd start from east coast and move towards west coast. And, Sun will get eclipsed from left (looking at the Sun) to right. In reality (images and videos I saw) was completely opposite. I'm sure some basic is not clicking in my brain. Did a quick search online, saw explanation for 5 deg tilt (and so upward/downwards path of the band of totality) but couldn't get answer to my specific puzzle in my mind. Thanks in advance to all who help.

shaileshs wrote: ↑Tue Apr 09, 2024 4:39 am Couldn't understand one basic aspect. Why the eclipse is seen starting from west coast in US to east coast in US.. Apparent motion of moon from east to waste should be faster than Sun's apparent motion from east to west.. So I was imagining it'd start from east coast and move towards west coast. And, Sun will get eclipsed from left (looking at the Sun) to right. In reality (images and videos I saw) was completely opposite. I'm sure some basic is not clicking in my brain. Did a quick search online, saw explanation for 5 deg tilt (and so upward/downwards path of the band of totality) but couldn't get answer to my specific puzzle in my mind. Thanks in advance to all who help.

Well, here goes.
Start with you standing on the earth and the earth spinning one revolution every day. So everything you can see in the solar system appears to be rotating in the same direction, from east to west. Then do this at the same time each day and notice that from one day to the next the moon has shifted in the sky so that it gradually moves eastward. That means that as it approaches the position of the sun it will be travelling from west to east across the face of the sun for an eclipse (or just slightly above or below the suns disc in the case of a normal new moon).

I came, I saw, and the eclipse conquered! That was my first ever total eclipse, and all I can say for now is however much you prepare and read to be ready, you're unprepared! Every aspect of the experience is something your brain has never processed before! And you only have a minute or so to take it all in, - the colour of the strange and sudden twilight is unlike any other twilight or dusk, seeing the corona with your own eyes, seeing an intense pink reddish arc below it (I really did not expect to see a touch of pink so well - and the Sun I am used to never shows any pink!) - and, oh wow, the return of the very first sunray after totality creates no ordinary diamond ring but one that shoots a laser beam straight into your eyes! Well worth taking the risk! (carefully)
And moments later, it’s all gone. GONE! Like waking up from a surreal and magical dream you wished went on and on.

For reference, here is the location of Lake Magog, Quebec and the eclipse path. It's the little lake just slightly South-West of Sherbrooke, at the point of the green arrow:

So someone help me with my math; where is my error?
If the sun/moon apparent diameter is ~ 32 arcminutes (just over 1/2 degree), and from one new moon to the next is 360 degrees around the earth, then there are 720 (more accurately 696) such diameters encircling the earth.
IF from eclipse start to totality - the moon touching one edge of sun and then same moon surface reaching the other edge of sun - took roughly 1.25 hours, then 1.25 hrs x 696 diameters (=870 hours) should equal a lunar month. But it doesn't. A lunar month is ~ 708 hours.
Why the discrepancy??

shaileshs wrote: ↑Tue Apr 09, 2024 4:39 am Couldn't understand one basic aspect. Why the eclipse is seen starting from west coast in US to east coast in US.. Apparent motion of moon from east to waste should be faster than Sun's apparent motion from east to west.. So I was imagining it'd start from east coast and move towards west coast. And, Sun will get eclipsed from left (looking at the Sun) to right. In reality (images and videos I saw) was completely opposite. I'm sure some basic is not clicking in my brain. Did a quick search online, saw explanation for 5 deg tilt (and so upward/downwards path of the band of totality) but couldn't get answer to my specific puzzle in my mind. Thanks in advance to all who help.

This video might help.

FLPhotoCatcher wrote: ↑Tue Apr 09, 2024 5:35 pm

shaileshs wrote: ↑Tue Apr 09, 2024 4:39 am Couldn't understand one basic aspect. Why the eclipse is seen starting from west coast in US to east coast in US.. Apparent motion of moon from east to waste should be faster than Sun's apparent motion from east to west.. So I was imagining it'd start from east coast and move towards west coast. And, Sun will get eclipsed from left (looking at the Sun) to right. In reality (images and videos I saw) was completely opposite. I'm sure some basic is not clicking in my brain. Did a quick search online, saw explanation for 5 deg tilt (and so upward/downwards path of the band of totality) but couldn't get answer to my specific puzzle in my mind. Thanks in advance to all who help.

This video might help.

Click to play embedded YouTube video.

Thanks - that was an excellent explanation and an info-packed video. The narrator talks a bit too fast for my 40-year MA in Mathematics degree removed mind to keep up while also understanding, so I had to slow it down to 75% speed! Also, as the guy said "geometry is weird"! To that aphorism I'd also add that it can take quite a lot of mental image gymnastics to truly understand 3D heavenly body movements. I've watched a few other videos from this channel and they're all very illuminating and "eclipse-dispelling". Highly recommended.

Here's an image from the 2024 eclipse, downtown Cleveland. Courtesy of David Petkiewicz (Cleveland.com).
We got very lucky with the weather, just had some thin high clouds.

tomatoherd wrote: ↑Tue Apr 09, 2024 4:30 pm So someone help me with my math; where is my error?
If the sun/moon apparent diameter is ~ 32 arcminutes (just over 1/2 degree), and from one new moon to the next is 360 degrees around the earth, then there are 720 (more accurately 696) such diameters encircling the earth.
IF from eclipse start to totality - the moon touching one edge of sun and then same moon surface reaching the other edge of sun - took roughly 1.25 hours, then 1.25 hrs x 696 diameters (=870 hours) should equal a lunar month. But it doesn't. A lunar month is ~ 708 hours.
Why the discrepancy??

more than 360 degrees
27.3 days to complete a revolution, but 29.5 days to change from New Moon to New Moon.

johnnydeep wrote: ↑Tue Apr 09, 2024 4:10 pm Lake Magog, Quebec

The picture was actually taken in the town of Magog, QC, on the shore of Lake Memphemagog. Lake Magog is another lake slightly east of Magog. This was Stan's mistake. He acknowledged my correction below my comment of this picture on his Instragram page.

aildoux wrote: ↑Thu Apr 11, 2024 4:43 pm

johnnydeep wrote: ↑Tue Apr 09, 2024 4:10 pm Lake Magog, Quebec

The picture was actually taken in the town of Magog, QC, on the shore of Lake Memphemagog. Lake Magog is another lake slightly east of Magog. This was Stan's mistake. He acknowledged my correction below my comment of this picture on his Instragram page.

Thanks for the correction. And that's Lake Memphremagog that the town of Magog is on the far north end of. Map:

Right. Actually spelled lake Memphremagog, with an r. My clerical error this time. Magog, QC, is on it's northern tip, and Newport, VT, is on it's southern tip.