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APOD: Diamond in the Sky (2020 Dec 18)

Posted: Fri Dec 18, 2020 5:05 am
by APOD Robot
Image Diamond in the Sky

Explanation: When the shadow of the Moon raced across planet Earth's southern hemisphere on December 14, sky watchers along the shadow's dark central path were treated to the only total solar eclipse of 2020. During the New Moon's shadow play this glistening diamond ring was seen for a moment, even in cloudy skies. Known as the diamond ring effect, the transient spectacle actually happens twice. Just before and immediately after totality, a thin sliver of solar disk visible behind the Moon's edge creates the appearance of a shiny jewel set in a dark ring. This dramatic snapshot from the path of totality in northern Patagonia, Argentina captures this eclipse's second diamond ring, along with striking solar prominences lofted beyond the edge of the Moon's silhoutte.

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Re: APOD: Diamond in the Sky (2020 Dec 18)

Posted: Fri Dec 18, 2020 12:25 pm
by orin stepanek
2020Dec14TSE_Ribas_IMG_9291c1024.jpg

Pretty Diamond Ring Effect! String of beads also! :wink: The clouds
make it even nicer!

Re: APOD: Diamond in the Sky (2020 Dec 18)

Posted: Fri Dec 18, 2020 5:17 pm
by Cousin Ricky
I’m glad someone got to see this one in person.

Re: APOD: Diamond in the Sky (2020 Dec 18)

Posted: Fri Dec 18, 2020 6:11 pm
by DL MARTIN
Question: Is it pure coincidence that the moon covers the sun so precisely?

Re: APOD: Diamond in the Sky (2020 Dec 18)

Posted: Fri Dec 18, 2020 6:43 pm
by Chris Peterson
DL MARTIN wrote: Fri Dec 18, 2020 6:11 pm Question: Is it pure coincidence that the moon covers the sun so precisely?
Yes. It didn't in the past, and it won't in the future.

Re: APOD: Diamond in the Sky (2020 Dec 18)

Posted: Fri Dec 18, 2020 7:43 pm
by Aristo
This is a great picture. I was wondering what the flame-like things on the surface of the Moon are.

Re: APOD: Diamond in the Sky (2020 Dec 18)

Posted: Fri Dec 18, 2020 7:49 pm
by neufer
Chris Peterson wrote: Fri Dec 18, 2020 6:43 pm
DL MARTIN wrote: Fri Dec 18, 2020 6:11 pm
Question: Is it pure coincidence that the moon covers the sun so precisely?
Yes. It didn't in the past, and it won't in the future.
We should have full total eclipses for the next 600 million years.
.........................................................
The apparent size of the Moon varies from
6% larger to 10% smaller than the Sun :arrow:

  • 1.06 = 33.5'/31.6'
    0.90 = 29.43'/32.7'
Assuming an a priori random (geometric) variation of apparent sizes over a scale of ~12,800,000 ( = [1.06/0.90]100) there is about a 1% chance of the Sun & Moon being such a "perfect" match.

Ergo: it is a coincidence... but not that much of one.

Re: APOD: Diamond in the Sky (2020 Dec 18)

Posted: Fri Dec 18, 2020 7:54 pm
by Chris Peterson
Aristo wrote: Fri Dec 18, 2020 7:43 pm This is a great picture. I was wondering what the flame-like things on the surface of the Moon are.
Do you mean the red prominences around the edges? They're on the Sun, not the Moon.

Re: APOD: Diamond in the Sky (2020 Dec 18)

Posted: Fri Dec 18, 2020 9:21 pm
by Aristo
Yes, I meant them. Wow!

Re: APOD: Diamond in the Sky (2020 Dec 18)

Posted: Sat Dec 19, 2020 12:13 am
by heehaw
Aristo wrote: Fri Dec 18, 2020 9:21 pmYes, I meant them. Wow!
Wow indeed. Those prominences and coronal mass ejections shoot huge amounts of solar material out into the solar system. And they don't even have a NASA to help do that! It is amazing! It seems to be done, somehow, by the sun's magnetic field: which is very similar to the Earth's magnetic field in average strength! But the Earth is solid (near its surface at least) while the Sun is almost completely ionized gas, core to surface.