APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

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APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by APOD Robot » Sun Sep 17, 2023 4:06 am

Image Moon Mountains Magnified during Ring of Fire Eclipse

Explanation: What are those dark streaks in this composite image of a solar eclipse? They are reversed shadows of mountains at the edge of the Moon. The center image, captured from Xiamen, China, has the Moon's center directly in front of the Sun's center. The Moon, though, was too far from the Earth to completely block the entire Sun. Light that streamed around the edges of the Moon is called a ring of fire. Images at each end of the sequence show sunlight that streamed through lunar valleys. As the Moon moved further in front of the Sun, left to right, only the higher peaks on the Moon's perimeter could block sunlight. Therefore, the dark streaks are projected, distorted, reversed, and magnified shadows of mountains at the Moon's edge. Bright areas are called Baily's Beads. Only people in a narrow swath across Earth's Eastern Hemisphere were able to view this full annular solar eclipse in 2020. Next month, though, a narrow swath crossing both North and South America will be exposed to the next annular solar eclipse. And next April, a total solar eclipse will be visible across North America.

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Re: APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by Sa Ji Tario » Sun Sep 17, 2023 3:05 pm

On one side of the lunar limb are the DÁlambert Mountains that look like saw teeth and through whose ravines and valleys sunlight filters to form the Baily Beads.

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Re: APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by VictorBorun » Sun Sep 17, 2023 6:37 pm

Sa Ji Tario wrote: Sun Sep 17, 2023 3:05 pm On one side of the lunar limb are the DÁlambert Mountains that look like saw teeth and through whose ravines and valleys sunlight filters to form the Baily Beads.
please which side is the one side?

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Re: APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by johnnydeep » Sun Sep 17, 2023 6:48 pm

I don't understand this image at all. Why did anything need to be "projected, distorted, reversed, and magnified" at all and why are there multiple arcs given that the Moon's limn only passes the edge of the Sun once on either side of the full eclipse process?
Last edited by johnnydeep on Mon Sep 18, 2023 2:40 pm, edited 1 time in total.
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moon mountains APOD 9/17/2023

Post by mona.baumgartel@gmail.com » Sun Sep 17, 2023 9:04 pm

Today's APOD is accompanied by insufficient information--as you can see by the other questions. Are all the rings what appears at the edge of the moon just before and after the eclipse? Are the rings on the left as the moon is coming into the eclipse? How much time elapses between the rings? Why is there no "diamond ring"?

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Re: APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by orin stepanek » Sun Sep 17, 2023 9:07 pm

BeadMountains_Letian_960.jpg
I wonder if Baily is willing to sell his beads! :evil:
TychoBoulder2_LRO_960.jpg
I love how an impact crater leaves such high mountains? :shock:
69ffc42ba1c739e25ed76fcaa6555a0e.jpg
Careful kitty don't fill that glass with wine! 😽
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Re: APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by mona.baumgartel@gmail.com » Sun Sep 17, 2023 9:10 pm

Today's APOD is accompanied by insufficient information--as you can see by the other questions. Are all the rings what appears at the edge of the moon just before and after the eclipse but would be seen in the same place? How much time elapses between the rings? Why is there no "diamond ring"?

Sa Ji Tario

Re: APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by Sa Ji Tario » Mon Sep 18, 2023 3:59 am

VictorBorun wrote: Sun Sep 17, 2023 6:37 pm
Sa Ji Tario wrote: Sun Sep 17, 2023 3:05 pm On one side of the lunar limb are the DÁlambert Mountains that look like saw teeth and through whose ravines and valleys sunlight filters to form the Baily Beads.
please which side is the one side?
Sorry, since this was over 35 years ago, I don't remember which side you asked, check both.

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Re: APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by johnnydeep » Mon Sep 18, 2023 2:43 pm

Sa Ji Tario wrote: Mon Sep 18, 2023 3:59 am
VictorBorun wrote: Sun Sep 17, 2023 6:37 pm
Sa Ji Tario wrote: Sun Sep 17, 2023 3:05 pm On one side of the lunar limb are the DÁlambert Mountains that look like saw teeth and through whose ravines and valleys sunlight filters to form the Baily Beads.
please which side is the one side?
Sorry, since this was over 35 years ago, I don't remember which side you asked, check both.
What was 35 years ago?
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Re: APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by alter-ego » Mon Sep 18, 2023 8:30 pm

mona.baumgartel@gmail.com wrote: Sun Sep 17, 2023 9:10 pm Today's APOD is accompanied by insufficient information--as you can see by the other questions. Are all the rings what appears at the edge of the moon just before and after the eclipse but would be seen in the same place? How much time elapses between the rings? Why is there no "diamond ring"?
Yes, I agree. Adding image capture and creation details would've been good.

The concentric ring structure in this image is essentially the same to that of the 2017 total eclipse. LIke the total eclipse, Wang probably took images around 3 per second. Yes, one 10-sec image set just before maximum eclipse, and one 10-sec set just after. As stated, the moon moves from right to left relative to the "stationary" sun. So no, the moon does not stay at the same (exact) location during the eclipse. The separated rings magnify the heights of the mountains. I stumbled across an out-of-plane (3D) variant for displaying baily-bead rings. By stacking the rings and sacrificing the central maximum-eclipse ring, the rings are not split in half and the temporal evolution is more clear to me.
 
Annular Eclipse Rings - 26 Dec 2019.jpg
 
Regarding the diamond-ring effect, it is identified during total eclipses when the "ring" is thin and the "diamond is bright and accentuated against the dark sky. For an annular eclipse, Baily's beads and "diamonds" still occur, but the thin "ring" is replaced by a broken annulus - a striking seen, but not a good diamond ring.

You can find further discussion in the original posting: https://apod.nasa.gov/apod/ap200622.html
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Re: APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by johnnydeep » Tue Sep 19, 2023 8:42 pm

alter-ego wrote: Mon Sep 18, 2023 8:30 pm
mona.baumgartel@gmail.com wrote: Sun Sep 17, 2023 9:10 pm Today's APOD is accompanied by insufficient information--as you can see by the other questions. Are all the rings what appears at the edge of the moon just before and after the eclipse but would be seen in the same place? How much time elapses between the rings? Why is there no "diamond ring"?
Yes, I agree. Adding image capture and creation details would've been good.

The concentric ring structure in this image is essentially the same to that of the 2017 total eclipse. LIke the total eclipse, Wang probably took images around 3 per second. Yes, one 10-sec image set just before maximum eclipse, and one 10-sec set just after. As stated, the moon moves from right to left relative to the "stationary" sun. So no, the moon does not stay at the same (exact) location during the eclipse. The separated rings magnify the heights of the mountains. I stumbled across an out-of-plane (3D) variant for displaying baily-bead rings. By stacking the rings and sacrificing the central maximum-eclipse ring, the rings are not split in half and the temporal evolution is more clear to me.
 
Annular Eclipse Rings - 26 Dec 2019.jpg
 
Regarding the diamond-ring effect, it is identified during total eclipses when the "ring" is thin and the "diamond is bright and accentuated against the dark sky. For an annular eclipse, Baily's beads and "diamonds" still occur, but the thin "ring" is replaced by a broken annulus - a striking seen, but not a good diamond ring.

You can find further discussion in the original posting: https://apod.nasa.gov/apod/ap200622.html
I still don't understand why the crescent slivers aren't all identical on each side. Aren't we seeing the same left or right limn of the Moon in either case?
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Re: APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by alter-ego » Tue Sep 19, 2023 11:32 pm

johnnydeep wrote: Tue Sep 19, 2023 8:42 pm
alter-ego wrote: Mon Sep 18, 2023 8:30 pm
mona.baumgartel@gmail.com wrote: Sun Sep 17, 2023 9:10 pm Today's APOD is accompanied by insufficient information--as you can see by the other questions. Are all the rings what appears at the edge of the moon just before and after the eclipse but would be seen in the same place? How much time elapses between the rings? Why is there no "diamond ring"?
Yes, I agree. Adding image capture and creation details would've been good.

The concentric ring structure in this image is essentially the same to that of the 2017 total eclipse. LIke the total eclipse, Wang probably took images around 3 per second. Yes, one 10-sec image set just before maximum eclipse, and one 10-sec set just after. As stated, the moon moves from right to left relative to the "stationary" sun. So no, the moon does not stay at the same (exact) location during the eclipse. The separated rings magnify the heights of the mountains. I stumbled across an out-of-plane (3D) variant for displaying baily-bead rings. By stacking the rings and sacrificing the central maximum-eclipse ring, the rings are not split in half and the temporal evolution is more clear to me.
 
Annular Eclipse Rings - 26 Dec 2019.jpg
 
Regarding the diamond-ring effect, it is identified during total eclipses when the "ring" is thin and the "diamond is bright and accentuated against the dark sky. For an annular eclipse, Baily's beads and "diamonds" still occur, but the thin "ring" is replaced by a broken annulus - a striking seen, but not a good diamond ring.

You can find further discussion in the original posting: https://apod.nasa.gov/apod/ap200622.html
I still don't understand why the crescent slivers aren't all identical on each side. Aren't we seeing the same left or right limn of the Moon in either case?
I don't understand your question. The shadows on the left side originate from the left lunar limb, and the right side shadows come from the right lunar limb. The two sides should not be identical. The right side shadows are pre-maximum eclipse, and the left side shadows are post-maximum eclipse. I used Stellarium to recreate the eclipse and circumstances, and made the graphic below to show against the APOD. Not sure if this helps.
 
Limbs and Baily Beads Graphic.jpg
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Re: APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by johnnydeep » Wed Sep 20, 2023 8:22 pm

alter-ego wrote: Tue Sep 19, 2023 11:32 pm
johnnydeep wrote: Tue Sep 19, 2023 8:42 pm
alter-ego wrote: Mon Sep 18, 2023 8:30 pm
Yes, I agree. Adding image capture and creation details would've been good.

The concentric ring structure in this image is essentially the same to that of the 2017 total eclipse. LIke the total eclipse, Wang probably took images around 3 per second. Yes, one 10-sec image set just before maximum eclipse, and one 10-sec set just after. As stated, the moon moves from right to left relative to the "stationary" sun. So no, the moon does not stay at the same (exact) location during the eclipse. The separated rings magnify the heights of the mountains. I stumbled across an out-of-plane (3D) variant for displaying baily-bead rings. By stacking the rings and sacrificing the central maximum-eclipse ring, the rings are not split in half and the temporal evolution is more clear to me.
 
Annular Eclipse Rings - 26 Dec 2019.jpg
 
Regarding the diamond-ring effect, it is identified during total eclipses when the "ring" is thin and the "diamond is bright and accentuated against the dark sky. For an annular eclipse, Baily's beads and "diamonds" still occur, but the thin "ring" is replaced by a broken annulus - a striking seen, but not a good diamond ring.

You can find further discussion in the original posting: https://apod.nasa.gov/apod/ap200622.html
I still don't understand why the crescent slivers aren't all identical on each side. Aren't we seeing the same left or right limn of the Moon in either case?
I don't understand your question. The shadows on the left side originate from the left lunar limb, and the right side shadows come from the right lunar limb. The two sides should not be identical. The right side shadows are pre-maximum eclipse, and the left side shadows are post-maximum eclipse. I used Stellarium to recreate the eclipse and circumstances, and made the graphic below to show against the APOD. Not sure if this helps.
 
Limbs and Baily Beads Graphic.jpg
Yes, but the left side of the Moon is shadowed in exactly the same way as it makes its way across Sun, isn't it? And ditto for the right side. So why aren't all the slivers/arcs on either side identical, instead of showing differing amounts of dark and light like in the APOD?

[ EDIT: woops, never mind! The differing arcs are due to the Moon mountains gradually becoming revealed or obscured due to passage over the Sun's limn. So all those arcs reflect only the progression of a small amount of Moon (the height of the mountains) across the Sun. Correct? ]
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Re: APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by alter-ego » Thu Sep 21, 2023 2:44 am

johnnydeep wrote: Wed Sep 20, 2023 8:22 pm
alter-ego wrote: Tue Sep 19, 2023 11:32 pm
johnnydeep wrote: Tue Sep 19, 2023 8:42 pm

I still don't understand why the crescent slivers aren't all identical on each side. Aren't we seeing the same left or right limn of the Moon in either case?
I don't understand your question. The shadows on the left side originate from the left lunar limb, and the right side shadows come from the right lunar limb. The two sides should not be identical. The right side shadows are pre-maximum eclipse, and the left side shadows are post-maximum eclipse. I used Stellarium to recreate the eclipse and circumstances, and made the graphic below to show against the APOD. Not sure if this helps.
 
Limbs and Baily Beads Graphic.jpg
Yes, but the left side of the Moon is shadowed in exactly the same way as it makes its way across Sun, isn't it? And ditto for the right side. So why aren't all the slivers/arcs on either side identical, instead of showing differing amounts of dark and light like in the APOD?

[ EDIT: woops, never mind! The differing arcs are due to the Moon mountains gradually becoming revealed or obscured due to passage over the Sun's limn. So all those arcs reflect only the progression of a small amount of Moon (the height of the mountains) across the Sun. Correct? ]
Ah, now I see what you were missing :idea: . Yes, as the moon's limb progresses across the sun's limb, the mountain peaks pierce the sun's edge first forming the shadow peaks, and within seconds, as more of the mountains block light, less unblocked sunlight passes through the valleys and the shadows fatten until the all the lunar terrain blocks most, if not all of the light, and you then have the last ring in the sequences.

Edit: The chronology I described is for the exiting sequence (left side) - mountain peaks are first to form shadows. However, on the right side, valleys are the first to pass light, and the mountain peaks are last shadows. Obvious because the first ring on the right is mostly dark (little valley light), and the first ring on the left side (nearest maximum eclipse) are the point shadows (mountains).
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Re: APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by johnnydeep » Thu Sep 21, 2023 2:34 pm

alter-ego wrote: Thu Sep 21, 2023 2:44 am
johnnydeep wrote: Wed Sep 20, 2023 8:22 pm
alter-ego wrote: Tue Sep 19, 2023 11:32 pm
I don't understand your question. The shadows on the left side originate from the left lunar limb, and the right side shadows come from the right lunar limb. The two sides should not be identical. The right side shadows are pre-maximum eclipse, and the left side shadows are post-maximum eclipse. I used Stellarium to recreate the eclipse and circumstances, and made the graphic below to show against the APOD. Not sure if this helps.
 
Limbs and Baily Beads Graphic.jpg
Yes, but the left side of the Moon is shadowed in exactly the same way as it makes its way across Sun, isn't it? And ditto for the right side. So why aren't all the slivers/arcs on either side identical, instead of showing differing amounts of dark and light like in the APOD?

[ EDIT: woops, never mind! The differing arcs are due to the Moon mountains gradually becoming revealed or obscured due to passage over the Sun's limn. So all those arcs reflect only the progression of a small amount of Moon (the height of the mountains) across the Sun. Correct? ]
Ah, now I see what you were missing :idea: . Yes, as the moon's limb progresses across the sun's limb, the mountain peaks pierce the sun's edge first forming the shadow peaks, and within seconds, as more of the mountains block light, less unblocked sunlight passes through the valleys and the shadows fatten until the all the lunar terrain blocks most, if not all of the light, and you then have the last ring in the sequences.

Edit: The chronology I described is for the exiting sequence (left side) - mountain peaks are first to form shadows. However, on the right side, valleys are the first to pass light, and the mountain peaks are last shadows. Obvious because the first ring on the right is mostly dark (little valley light), and the first ring on the left side (nearest maximum eclipse) are the point shadows (mountains).
Thanks. Still uncertain about something: per the text, the Moon moved in front of the Sun from left to right. That means the right limn Moon mountains started blocking the Sun first. Where is that first blockage - which would extend only a short way along the limn - shown in the APOD? Also, is the text implying that the shadows stretched out by the presentation of arcs here mimics the relative height of the Moon mountains?
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Re: APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by Chris Peterson » Thu Sep 21, 2023 3:00 pm

johnnydeep wrote: Thu Sep 21, 2023 2:34 pm
alter-ego wrote: Thu Sep 21, 2023 2:44 am
johnnydeep wrote: Wed Sep 20, 2023 8:22 pm

Yes, but the left side of the Moon is shadowed in exactly the same way as it makes its way across Sun, isn't it? And ditto for the right side. So why aren't all the slivers/arcs on either side identical, instead of showing differing amounts of dark and light like in the APOD?

[ EDIT: woops, never mind! The differing arcs are due to the Moon mountains gradually becoming revealed or obscured due to passage over the Sun's limn. So all those arcs reflect only the progression of a small amount of Moon (the height of the mountains) across the Sun. Correct? ]
Ah, now I see what you were missing :idea: . Yes, as the moon's limb progresses across the sun's limb, the mountain peaks pierce the sun's edge first forming the shadow peaks, and within seconds, as more of the mountains block light, less unblocked sunlight passes through the valleys and the shadows fatten until the all the lunar terrain blocks most, if not all of the light, and you then have the last ring in the sequences.

Edit: The chronology I described is for the exiting sequence (left side) - mountain peaks are first to form shadows. However, on the right side, valleys are the first to pass light, and the mountain peaks are last shadows. Obvious because the first ring on the right is mostly dark (little valley light), and the first ring on the left side (nearest maximum eclipse) are the point shadows (mountains).
Thanks. Still uncertain about something: per the text, the Moon moved in front of the Sun from left to right. That means the right limn Moon mountains started blocking the Sun first. Where is that first blockage - which would extend only a short way along the limn - shown in the APOD? Also, is the text implying that the shadows stretched out by the presentation of arcs here mimics the relative height of the Moon mountains?
Sorry, hate to be pedantic (okay, I don't hate it all that much). But it's "limb". Not "limn".
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Re: APOD: Moon Mountains Magnified during Ring... (2023 Sep 17)

Post by johnnydeep » Thu Sep 21, 2023 3:31 pm

Chris Peterson wrote: Thu Sep 21, 2023 3:00 pm
johnnydeep wrote: Thu Sep 21, 2023 2:34 pm
alter-ego wrote: Thu Sep 21, 2023 2:44 am
Ah, now I see what you were missing :idea: . Yes, as the moon's limb progresses across the sun's limb, the mountain peaks pierce the sun's edge first forming the shadow peaks, and within seconds, as more of the mountains block light, less unblocked sunlight passes through the valleys and the shadows fatten until the all the lunar terrain blocks most, if not all of the light, and you then have the last ring in the sequences.

Edit: The chronology I described is for the exiting sequence (left side) - mountain peaks are first to form shadows. However, on the right side, valleys are the first to pass light, and the mountain peaks are last shadows. Obvious because the first ring on the right is mostly dark (little valley light), and the first ring on the left side (nearest maximum eclipse) are the point shadows (mountains).
Thanks. Still uncertain about something: per the text, the Moon moved in front of the Sun from left to right. That means the right limn Moon mountains started blocking the Sun first. Where is that first blockage - which would extend only a short way along the limn - shown in the APOD? Also, is the text implying that the shadows stretched out by the presentation of arcs here mimics the relative height of the Moon mountains?
Sorry, hate to be pedantic (okay, I don't hate it all that much). But it's "limb". Not "limn".
Pedantry is quite alright here, and you're right of course. I admit to being unsure about limn/limb when I wrote it (many times!), but failed to check. I'll use as my excuse the etymology of "limn", which has to do with light:
https://www.merriam-webster.com/dictionary/limn#did-you-know wrote:Allow us to shed some light on the history of limn, a word with lustrous origins. Limn traces to the Anglo-French verb aluminer and ultimately to the Latin illuminare, which means "to illuminate." Its use as an English verb dates from the days of Middle English; at first, limn referred to the action of illuminating (that is, decorating) medieval manuscripts with gold, silver, or brilliant colors. William Shakespeare extended the term to painting in his poem Venus and Adonis: "Look when a painter would surpass the life / In limning out a well-proportioned steed...."
So, you could say that during a lunar eclipse, the limb of the Moon is being limned - in shadow! - by the Sun, or that the limb of the Moon is delimning the Sun. Or something like that. Oh, and also, this APOD is limning the limb of the Moon! (Though is didn't do it brightly enough to limn my shadowed mind.) Ok, I'll stop now.
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