Annular eclipse — Tokyo at breakfast (2012)
On the morning of 21 May 2012 Tokyo saw its first annular eclipse in 173 years, a ring of fire lasting about five minutes around 7:32 local time, during the morning commute. The path ran from southern China, Taiwan and Japan to the western United States.
📍 Visible from where you are right now — computed in your browser
Available views: Orbit ✓ · Sky ✓
The story
At about 7:32 on the morning of 21 May 2012, a ring of fire appeared in the sky over central Tokyo. It was the hour when people were travelling to work and children were heading to school. Tokyo had not seen an annular eclipse since 1839, a gap of 173 years. So the event is remembered less as an astronomy show and more as a morning when a whole giant city stopped for a moment and looked up.
The Moon's shadow began at sunrise over Guangxi in southern China. It then passed over Guangzhou, Hong Kong, Xiamen and Taipei in northern Taiwan before reaching Japan. There it crossed southern Kyushu and Shikoku and a wide stretch of land linking Osaka, Nagoya and Tokyo. About 100 million people in China and Japan were in places where the ring could be seen.
The shadow then crossed the Pacific Ocean to the western United States. It passed over Oregon, California, Nevada, Utah, Arizona and New Mexico, and ended at sunset in Texas. In the United States, however, the eclipse happened on the evening of 20 May. The International Date Line explains this: the same moment was the morning of the 21st on its western side and the evening of the 20th on its eastern side.
Over Tokyo the ring lasted about 5 minutes 3 seconds. The Sun was still low in the eastern sky, so many people searched for open ground without tall buildings in the way. Many Japanese schools gathered pupils in the playground to watch together, and television stations broadcast the eclipse live that morning. The orbit view reproduces the Moon's shadow travelling from Asia across the Pacific to North America.
Viewing guide — where, when, how
The ring could be seen from southern China, Hong Kong and northern Taiwan, then across southern Kyushu, Shikoku, Kansai, Chubu and Kanto in Japan. After crossing the Pacific it was seen on the evening of 20 May from Oregon, northern California, Nevada, Utah, Arizona, New Mexico and Texas. Elsewhere in East Asia, and across much of the North Pacific and western North America, it appeared as a partial eclipse, with part of the Sun covered.
A morning eclipse happens with the Sun low in the sky, where buildings or hills can easily block it. An open view to the east was therefore needed. A low Sun is no less bright, so it must never be viewed without a filter. Certified eclipse glasses should stay on from start to finish, and telescopes or cameras need a solar filter fitted over the front.
The sky view follows the Sun over Tokyo that morning and slows down to reproduce the moment the ring closes. Changing the viewing place to Beijing shows the shape of that morning's partial eclipse, and changing it to Albuquerque shows the ring on the evening before. The switch also shows how the date line gives the same eclipse two different dates.
See this for yourself — open that sky at that moment · replay the moment in the orbit view
Why this eclipse is special
What made this eclipse special was its scale more than its science. Because the ring passed over several huge cities at once, an enormous number of people saw a single annular eclipse with their own eyes. That also made safety education important. Eclipse glasses were handed out and broadcasts warned people not to look at the Sun with bare eyes, on a very large scale.
An eclipse seen by many people at once also helps science. When the same eclipse is photographed from places hundreds of kilometres apart, the moments when the ring closes and opens can be compared. Such records help measure the height of mountains along the Moon's edge and the size of the Sun more accurately. Differences that one photograph from one place cannot reveal can be found by putting records from many places together.
In 2012, just over two weeks later on 6 June, Venus also crossed in front of the Sun in an event called a transit of Venus. That spring offered both a day when the Moon covered the Sun and a day when Venus crossed it. The next transit of Venus will not happen until 2117, which made this spring a rare chance for observers.
Background and earlier eclipses
This eclipse belongs to Saros 128. The previous member of the series was the annular eclipse of 10 May 1994, which crossed the United States. The next is the annular eclipse of 1 June 2030, whose path crosses Hokkaido in Japan. Japan therefore gets two rings from the same series eighteen years apart.
Tokyo's previous annular eclipse was in September 1839. Calculations show that the next such annular eclipse over Tokyo and Japan's other big cities will come in 2312. That is almost three hundred years away, so the morning of 2012 was a once-in-centuries chance for the people of Tokyo. Even among annular eclipses, a path that passes over a huge city is this rare.
The American part of the path overlapped with the path of the 14 October 2023 annular eclipse in New Mexico. That made Albuquerque one of the few cities to see two rings of fire within a single generation. The second ring became especially famous because it happened during the city's hot-air balloon festival. The two eclipses can be compared by switching between viewing places.
FAQ
How long did the ring last over Tokyo?
About 5 minutes 3 seconds. The ring appeared around 7:32 a.m. local time on 21 May (22:32 UT on 20 May), with the Sun still low in the eastern sky.
Was it visible outside the path?
Yes. From Greenland to Hawaii, and from eastern Indonesia to western North America, it appeared as a partial eclipse, with part of the Sun covered. The ring itself could only be seen inside the path: in southern China, Taiwan and Japan on the morning of 21 May, and in the western United States on the evening of 20 May.
Why is the US date 20 May?
The same moment was the morning of the 21st west of the date line, in Japan, and the evening of the 20th east of it, in the United States.
When is Tokyo's next annular eclipse?
It is calculated for 2312. For Japan as a whole, the next ring crosses Hokkaido on 1 June 2030.
Related
- The 2030 annular over Hokkaido
- The 2023 annular over the US West
- The 2012 transit of Venus
- The 2010 annular — longest of the millennium
- The Sun — object index
Times and figures are approximate — verify with official sources when planning travel. Simulation uses J2000 mean elements.