AYATSUKA Yuji (綾塚 祐二)
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ayatsuka.bsky.social
AYATSUKA Yuji (綾塚 祐二)
@ayatsuka.bsky.social
58 followers 41 following 150 posts
Atmospheric Optics, Science Fiction, Human Computer Interaction
https://www.asahi-net.or.jp/~cg1y-aytk
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ayatsuka.bsky.social
AYATSUKA Yuji (綾塚 祐二) @ayatsuka.bsky.social · Jun 24
Finally, my paper on "Sky-Color Regression" has been published!
Ayatsuka, Y.: Revealing halos concealed by cirrus clouds, Atmos. Meas. Tech., 17, 3739–3750, doi.org/10.5194/amt-..., 2024
Revealing halos concealed by cirrus clouds
Abstract. Many types of halos (including arcs) appear in the sky. Each type of halo corresponds to the shape and orientation of ice crystals in clouds, and reflects the state of the atmosphere; theref...
doi.org
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
ayatsuka.bsky.social
Beer!
June 26, 2025 at 1:02 PM
ayatsuka.bsky.social
Tea-colored lantern? :-)
June 23, 2025 at 12:16 PM
ayatsuka.bsky.social
Summer solstice
June 22, 2025 at 12:48 AM
ayatsuka.bsky.social
22-degree halo (with a faint circumscribed halo?)
June 14, 2025 at 1:24 AM
Reposted by AYATSUKA Yuji (綾塚 祐二)
arakencloud.bsky.social
一緒に本を育てた証を、本に刻んで残しませんか？

不眠天気という本を書いています。
先読みをやりますので、ぜひ意見・感想等を頂戴したいです。ご参加いただいた方は巻末にお名前を掲載します。どなたでもご参加大歓迎です。

ご協力よろしくお願いしますー！

申込：https://forms.gle/zuWUgrjPw5MZaR3aA
June 14, 2025 at 1:19 AM
ayatsuka.bsky.social
Nejibana
June 8, 2025 at 10:02 AM
Reposted by AYATSUKA Yuji (綾塚 祐二)
apod.shinyakato.dev
🔭 Rainbow Airglow over the Azores

Image Credit & Copyright: Miguel Claro (TWAN); Rollover Annotation: Judy Schmidt

apod.nasa.gov/apod/ap25060...
A starfield is seen over water, clouds, and the lights of a city below. The starfield is oddly not black, but shows a repeating assortment of transparent colors diagonally from the lower left to the upper right. Please see the explanation for more detailed information.
June 3, 2025 at 8:00 AM
Reposted by AYATSUKA Yuji (綾塚 祐二)
apod.shinyakato.dev
🔭 Mars in the Loop

Image Credit & Copyright: Tunc Tezel (TWAN)

apod.nasa.gov/apod/ap25053...
This composite of images spaced a weather-permitting 5 to 9 days apart, from 2024 September 19 (top right) through 2025 May 18 (bottom left), faithfully traces ruddy-colored Mars as it makes a clockwise loop through the constellations Gemini and Cancer in planet Earth's night sky. You can connect the dots and dates with your cursor over the image, but be sure to check out this animation of the Red Planet's 2024/25 retrograde motion. Of course Mars didn't actually reverse the direction of its orbit. Instead, the apparent backwards motion with respect to the background stars is a reflection of the orbital motion of Earth itself. Retrograde motion can be seen each time Earth overtakes and laps planets orbiting farther from the Sun, the Earth moving more rapidly through its own relatively close-in orbit. In this case Mars' apparent eastward motion began to reverse around December 8, when it seemed to linger near open star cluster M44 in Cancer. After wandering back to the west, under Gemini's bright stars Castor and Pollux, Mars returned to pose near M44 by early May. At its brightest near opposition on 2025 January 16, Mars was a mere 96 million kilometers away.
May 30, 2025 at 8:00 AM