Starship Asterisk*

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.

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?

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.

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"?

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

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?

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

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? ]

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 . 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).

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?

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 . 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".

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...."