APOD: Ice Halos over Bavaria (2023 Dec 20)

[APOD Robot]

Ice Halos over Bavaria

Explanation: What's causing those unusual sky arcs? Ice crystals. While crossing a field of fresh snow near Füssen, Bavaria, Germany, earlier this month, the photographer noticed that he had entered an ice fog. For suspended water to freeze into an ice fog requires quite cold temperatures, and indeed the air temperature on this day was measured at well below zero. The ice fog reflected light from the Sun setting behind St. Coleman Church. The result was one of the greatest spectacles the photographer has ever seen. First, the spots in the featured picture are not background stars but suspended ice and snow. Next, two prominent ice halos are visible: the 22-degree halo and the 46-degree halo. Multiple arcs are also visible, including, from top to bottom, antisolar (subsun), circumzenithal, Parry, tangent, and parhelic (horizontal). Finally, the balloon shaped curve connecting the top arc to the Sun is the rarest of all: it is the heliac arc, created by reflection from the sides of hexagonally shaped ice crystals suspended in a horizontal orientation.

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[Ann]

Wow, that's a truly spectacular and fantastic image!

Ice Halos over Bavaria. Image Credit & Copyright: Bastian Werner

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The heliac arc looks like a heart!

APOD Robot wrote:

Finally, the balloon shaped curve connecting the top arc to the Sun is the rarest of all: it is the heliac arc, created by reflection from the sides of hexagonally shaped ice crystals suspended in a horizontal orientation.

Types of snow and ice crystals

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Plates of ice.png (45.23 KiB) Viewed 22983 times

Are we talking about ice crystals like the fourth from left in the top row, the plates of ice, suspended in a horizontal orientation? These things?

Ann

[johnnydeep]

Very impressive panoply of "arcs"! If this doesn't set a record for the most arc types in a single event, it must be pretty close.

[Avalon]

Such a wonderful image and educational, as well. I would have made it my Christmas card!

[Guest]

Wow, that's a truly spectacular and fantastic image!

Ice Halos over Bavaria. Image Credit & Copyright: Bastian Werner

---

The heliac arc looks like a heart!

APOD Robot wrote:

Finally, the balloon shaped curve connecting the top arc to the Sun is the rarest of all: it is the heliac arc, created by reflection from the sides of hexagonally shaped ice crystals suspended in a horizontal orientation.

Types of snow and ice crystals

---

Plates of ice.png

Are we talking about ice crystals like the fourth from left in the top row, the plates of ice, suspended in a horizontal orientation? These things?

Ann

Which is most popular? I mean the shape of ice crystals?

[Unely1965]

Wow, that's a truly spectacular and fantastic image!

Ice Halos over Bavaria. Image Credit & Copyright: Bastian Werner

---

The heliac arc looks like a heart!

APOD Robot wrote:

Finally, the balloon shaped curve connecting the top arc to the Sun is the rarest of all: it is the heliac arc, created by reflection from the sides of hexagonally shaped ice crystals suspended in a horizontal orientation.

Types of snow and ice crystals

---

Plates of ice.png

Are we talking about ice crystals like the fourth from left in the top row, the plates of ice, suspended in a horizontal orientation? These things?

Ann

Which is most popular? I mean the shape of ice crystals?

Stellar dendrites?? Is that right?

[sabnsy45]

Wow, that's a truly spectacular and fantastic image!

Ice Halos over Bavaria. Image Credit & Copyright: Bastian Werner

---

The heliac arc looks like a heart!

APOD Robot wrote:

Finally, the balloon shaped curve connecting the top arc to the Sun is the rarest of all: it is the heliac arc, created by reflection from the sides of hexagonally shaped ice crystals suspended in a horizontal orientation.

geometry dash subzero

Types of snow and ice crystals

---

Plates of ice.png

Are we talking about ice crystals like the fourth from left in the top row, the plates of ice, suspended in a horizontal orientation? These things?

Ann

Is ice crystals the most popular?

[Ann]

Wow, that's a truly spectacular and fantastic image!

Ice Halos over Bavaria. Image Credit & Copyright: Bastian Werner

---

The heliac arc looks like a heart!

Types of snow and ice crystals

---

Plates of ice.png

Are we talking about ice crystals like the fourth from left in the top row, the plates of ice, suspended in a horizontal orientation? These things?

Ann

Which is most popular? I mean the shape of ice crystals?

Stellar dendrites?? Is that right?

Don't know, but I think that plates of ice are the most popular if you want to see ice halos!

Ann

[arabrockall]

Wow, that's a truly spectacular and fantastic image!

Ice Halos over Bavaria. Image Credit & Copyright: Bastian Werner

---

The heliac arc looks like a heart!

APOD Robot wrote:

Finally, the balloon shaped curve connecting the top arc to the Sun is the rarest of all: it is the heliac arc, created by reflection from the sides of hexagonally shaped ice crystals suspended in a horizontal orientation.

geometry dash

Types of snow and ice crystals

---

Plates of ice.png

Are we talking about ice crystals like the fourth from left in the top row, the plates of ice, suspended in a horizontal orientation? These things?

Ann

Is ice crystals the most popular?

No, I think the most common crystals are hexagonal plates

[johnnydeep]

Wow, that's a truly spectacular and fantastic image!

Ice Halos over Bavaria. Image Credit & Copyright: Bastian Werner

---

The heliac arc looks like a heart!
geometry dash

Types of snow and ice crystals

---

Plates of ice.png

Are we talking about ice crystals like the fourth from left in the top row, the plates of ice, suspended in a horizontal orientation? These things?

Ann

Is ice crystals the most popular?

No, I think the most common crystals are hexagonal plates

Umm, what's the difference between crystals 1 and 4 in that chart? It just looks like there are two of crystal 1 shown for "crystal" 4.

[Chris Peterson]

Is ice crystals the most popular?

No, I think the most common crystals are hexagonal plates

Umm, what's the difference between crystals 1 and 4 in that chart? It just looks like there are two of crystal 1 shown for "crystal" 4.

I think the crystal formations are identical, and the image is just emphasizing that a scattered cloud of them will result in different halo phenomena than you get in very still air where they will tend to align in horizontal alignment.

[johnnydeep]

No, I think the most common crystals are hexagonal plates

Umm, what's the difference between crystals 1 and 4 in that chart? It just looks like there are two of crystal 1 shown for "crystal" 4.

I think the crystal formations are identical, and the image is just emphasizing that a scattered cloud of them will result in different halo phenomena than you get in very still air where they will tend to align in horizontal alignment.

Ok, so the difference between isolated hexagonal crystals and agglomerations of those same hexagons "aligned" together. Is actually joining together - or maybe forming joined in the first place - a possibility in the air?

[Chris Peterson]

Umm, what's the difference between crystals 1 and 4 in that chart? It just looks like there are two of crystal 1 shown for "crystal" 4.

I think the crystal formations are identical, and the image is just emphasizing that a scattered cloud of them will result in different halo phenomena than you get in very still air where they will tend to align in horizontal alignment.

Ok, so the difference between isolated hexagonal crystals and agglomerations of those same hexagons "aligned" together. Is actually joining together - or maybe forming joined in the first place - a possibility in the air?

I don't think they join. It's just that in still air they orient themselves horizontally (like little parachutes), and in turbulent air their orientations are random.

[johnnydeep]

I think the crystal formations are identical, and the image is just emphasizing that a scattered cloud of them will result in different halo phenomena than you get in very still air where they will tend to align in horizontal alignment.

Ok, so the difference between isolated hexagonal crystals and agglomerations of those same hexagons "aligned" together. Is actually joining together - or maybe forming joined in the first place - a possibility in the air?

I don't think they join. It's just that in still air they orient themselves horizontally (like little parachutes), and in turbulent air their orientations are random.