AYATSUKA Yuji (綾塚 祐二)
LightNews LightNews
banner
ayatsuka.bsky.social
AYATSUKA Yuji (綾塚 祐二)
@ayatsuka.bsky.social
59 followers 41 following 160 posts
Atmospheric Optics, Science Fiction, Human Computer Interaction
https://www.asahi-net.or.jp/~cg1y-aytk
Posts Replies Media Videos
Pinned
ayatsuka.bsky.social
AYATSUKA Yuji (綾塚 祐二) @ayatsuka.bsky.social · Jan 12
My original halo simulator "HaloPlot" under development:
- 48 bit color process
- multiple ray path filters for each type of crystals
ayatsuka.bsky.social
pyramidal plate arcs
February 3, 2026 at 9:49 AM
ayatsuka.bsky.social
これは @arakencloud.bsky.social せんせいにご紹介しないわけにはいかないクラフトビール :-)
January 23, 2026 at 10:00 AM
ayatsuka.bsky.social
1/17, 8:30-9:00, halo display at Hakodate
January 18, 2026 at 6:07 AM
ayatsuka.bsky.social
My original halo simulator "HaloPlot" under development:
- 48 bit color process
- multiple ray path filters for each type of crystals
January 12, 2026 at 10:26 AM
Reposted by AYATSUKA Yuji (綾塚 祐二)
apod.shinyakato.dev
🔭 Ice Halos by Moonlight and Sunlight

Image Credit & Copyright: Antonella Cicala

apod.nasa.gov/apod/ap26010...
Both Moon and Sun create beautiful ice halos in planet Earth's sky. In fact, the two brightest celestial beacons are each surrounded by a complex of ice halos in these photos of the sky above Chamonix-Mont-Blanc in France. The panels were recorded one night (left) and the following day at the end of December 2025. Similar ice halos appear in moonlight and sunlight because they are all formed through the geometry of flat, hexagonal ice crystals. The ice crystals reflect and refract light as they flutter in the cold atmosphere above the mountain resort. In the pictures both Moon and Sun are surrounded by a more commonly seen 22 degree circular halo. Bright and sometimes colorful patches at the intersections of the 22 degree circular halos with the indicated parselenic and parhelic arcs are also known as Moon dogs and Sun dogs.
January 9, 2026 at 8:00 AM
ayatsuka.bsky.social
Season's Greetings
January 2, 2026 at 2:13 AM
Reposted by AYATSUKA Yuji (綾塚 祐二)
apod.shinyakato.dev
🔭 Red Sprites and Circular Elves Lightning over Italy

Image Credit & Copyright: Valter Binotto

apod.nasa.gov/apod/ap25122...
Trees on a hilltop are seen in a starry sky but with clouds on the far horizon. A strange red circular band of light is seen in the sky. Near this band's center, some bright jellyfish like structures are visible. Please see the explanation for more detailed information.
December 23, 2025 at 8:00 AM
ayatsuka.bsky.social
Ice Crystals with Ray Paths
December 26, 2025 at 2:30 PM
ayatsuka.bsky.social
note.com/ayatsuka_yuj...
Search for Angle X｜綾塚 祐二
各種説明のための素材となる図・画像や、それを描く・作るためのツール (プログラム) 類をちょこちょこと作っています。最近はピラミダルハロ (odd radius halo) の種類とピラミダル氷晶に対する入出射面との関係を図示するためのものをいろいろ作ってました。氷晶を描いて (ワイヤフレームも面の塗りつぶしも)、ぐるぐる回したりするところまでは一年前に作ってあったので、「指定した二つの面に別の色...
note.com
November 18, 2025 at 1:30 PM
Reposted by AYATSUKA Yuji (綾塚 祐二)
apod.shinyakato.dev
🔭 A Super Lunar Corona

Image Credit & Copyright: Eric Houck

star.ucl.ac.uk/~apod/apod/a...
The Moon is pictured in the centre. ARound the Moon are colourful rings. The rings are nearly circular but have gaps. This but structured clouds are seen around the scene and at the bottom of the frame. Please see the explanation for more detailed information.
November 12, 2025 at 8:00 AM
Reposted by AYATSUKA Yuji (綾塚 祐二)
apod.shinyakato.dev
🔭 Comet Lemmon Beyond Lomnický Peak

Image Credit & Copyright: Robert Barsa

star.ucl.ac.uk/~apod/apod/a...
An image of the night sky over distant mountains features a comet with long tails. One of the tails goes nearly to the edge of the picture on the upper right. Please see the explanation for more detailed information.
November 4, 2025 at 8:00 AM
ayatsuka.bsky.social
Beer!
October 17, 2025 at 3:29 PM
ayatsuka.bsky.social
22-degree halo, circumscribed halo, parhelion, parhelic circle, 46-degree halo
September 22, 2025 at 6:20 AM
Reposted by AYATSUKA Yuji (綾塚 祐二)
apod.shinyakato.dev
🔭 A Two Percent Moon

Image Credit & Copyright: Marina Prol

apod.nasa.gov/apod/ap25083...
A young crescent moon can be hard to see. That's because when the Moon shows it's crescent phase (young or old) it can never be far from the Sun in planet Earth's sky. And even though the sky is still bright, a slender sunlit lunar crescent is cleary visible in this early evening skyscape. The telephoto snapshot was captured on August 24, with the Moon very near the western horizon at sunset. Seen in a narrow crescent phase about 1.5 days old, the visible sunlit portion is a mere two percent of the surface of the Moon's familiar nearside. At the Canary Islands Space Centre, a steerable radio dish for communication with spacecraft is titled in the direction of the two percent Moon. The sunset sky's pastel pinkish coloring is partly due to fine sand and dust from the Sahara Desert blown by the prevailing winds.
August 30, 2025 at 8:00 AM
ayatsuka.bsky.social
Don't look at the sun directory, when you watch phenomena near the sun!
September 2, 2025 at 9:21 AM
Reposted by AYATSUKA Yuji (綾塚 祐二)
apod.shinyakato.dev
🔭 Fishing for the Moon

Image Credit & Copyright: Marco Bellelli

apod.nasa.gov/apod/ap25082...
How big is planet Earth's Moon? Compared to other moons of the Solar System, it's number 5 on the largest to smallest ranked list, following Jupiter's moon Ganymede, Saturn's moon Titan, and Jovian moons Callisto and Io. Continuing the list, the Moon comes before Jupiter's Europa and Neptune's Triton. It's also larger than dwarf planets Pluto and Eris. With a diameter of 3,475 kilometers the Moon is about 1/4 the size of Earth though, and that does make it the largest moon when compared to the size of its parent Solar System planet. Of course in this serene, twilight sea and skyscape, August's rising Full Moon still appears small enough to be caught in the nets of an ancient fishing rig. The telephoto snapshot was taken along the Italian Costa dei Trabocchi, on the Adriatic Sea.
August 23, 2025 at 8:00 AM
ayatsuka.bsky.social
pyramidal halos! (9, 18, 20, 22, 23, 24, 35, 46)
August 26, 2025 at 9:31 AM
ayatsuka.bsky.social
The secondary rainbow appeared without the primary rainbow (because the sun's altitude was too high).
August 21, 2025 at 12:11 PM
ayatsuka.bsky.social
Pyramidal crystals and the surfaces through which the rays enter and exit for each odd radius halo. [prototype]
August 10, 2025 at 10:01 AM
ayatsuka.bsky.social
Pyramidal halos!
July 25, 2025 at 2:01 PM
ayatsuka.bsky.social
Cloud iridescence
July 20, 2025 at 4:59 AM
ayatsuka.bsky.social
Pyramidal halos! (9-, 20-, 24-, 35- degrees) + (normal 22- and 46-degree halos
July 19, 2025 at 7:37 AM
ayatsuka.bsky.social
Summer greetings
July 18, 2025 at 3:40 AM
ayatsuka.bsky.social
Circumhorizontal arc
July 10, 2025 at 4:24 AM
ayatsuka.bsky.social
22-degree halo, circumscribed halo, 46-degree halo
June 29, 2025 at 5:28 AM