A total solar eclipse occurred at the Moon's descending node of the orbit on July 22, 2009,^[1][2][3] with a magnitude of 1.07991. It was the longest total solar eclipse during the 21st century with totality lasting a maximum of 6 minutes and 38.86 seconds off the coast of Southeast Asia,^[4] causing tourist interest in eastern China, Pakistan, Japan, India, Nepal and Bangladesh. Its greatest magnitude was 1.07991, occurring only 6 hours, 18 minutes after perigee.

This was the second eclipse for the mid-2009 eclipse season, with the first having been the July 2009 lunar eclipse. The third eclipse of the season was the August 2009 lunar eclipse.^[4][5][6]

The solar eclipse was the 37th eclipse of the 136th Saros cycle, which began with a partial eclipse on June 14, 1360, and is expected to conclude with a partial eclipse on July 30, 2622.^{[citation needed]}

A partial eclipse was seen within the broad path of the Moon's penumbra, including most of Southeast Asia (all of Pakistan, India and China) and north-eastern Oceania.

The total eclipse was visible from a narrow corridor through northern India, eastern Nepal, northern Bangladesh, Bhutan, the northern tip of Myanmar, central China and the Pacific Ocean, including the northern part of the Ryukyu Islands, the whole Volcano Islands except South Iwo Jima, Marshall Islands, and Kiribati.

Totality was visible in many large cities, including Dhaka and Dinajpur, and Chapai Nawabganj district in Bangladesh; Surat, Vadodara, Bhopal, Varanasi, Patna, Gaya, Siliguri, Tawang and Guwahati in India; and Chengdu, Nanchong, Chongqing, Yichang, Jingzhou, Wuhan, Huanggang, Hefei, Hangzhou, Wuxi, Huzhou, Suzhou, Jiaxing, Ningbo, Shanghai as well as over the Three Gorges Dam in China. However, in Shanghai, the largest city in the eclipse's path, the view was obscured by heavy clouds.^[7][8] According to NASA, the Japanese island Kitaio Jima was predicted to have the best viewing conditions^[9][10] featuring both longer viewing time (being the closest point of land to the point of greatest eclipse) and lower cloud cover statistics than all of continental Asia.

The eclipse, and the reaction of thousands of observers at Varanasi was captured by the Science Channel Wonders of the Universe series hosted by Brian Cox.^[11]

This eclipse may be the most-viewed total solar eclipse in history, with 30 million people in Shanghai and Hangzhou alone.^[12]

Thousands of pilgrims gathered on the banks of the Ganges River in Varanasi, India to experience the eclipse as a religious or spiritual event. Some people expected that there would be a relationship, either positive or negative, between their health and the occurrence of the eclipse.^[13]

Indian scientists observed the solar eclipse from an Indian Air Force plane.^[14]

The Chinese government used the opportunity to provide scientific education and to dispel any superstition. A flight by China Eastern Airlines from Wuhan to Shanghai took a slight detour and followed the course of the eclipse to allow longer observation time for the scientists on board.

Observers in Japan were excited by the prospect of experiencing the first eclipse in 46 years, but found the experience dampened by cloudy skies obscuring the view.

In Bangladesh, where the eclipse lasted approximately 3 minutes and 44 seconds, thousands of people were able to witness the eclipse despite rain and overcast skies.

This solar eclipse was the longest total solar eclipse to occur in the 21st century, and will not be surpassed in duration until 13 June 2132 (Saros 139, ascending node) which will last for 6 minutes and 55 seconds. Totality lasted for up to 6 minutes and 38.86 seconds (0.14 seconds shorter than 6 minutes and 39 seconds), with the maximum eclipse occurring in the ocean at 02:35:21 UTC about 100 km south of the Bonin Islands, southeast of Japan. The uninhabited North Iwo Jima island was the landmass with totality time closest to maximum, while the closest inhabited point was Akusekijima, where the eclipse lasted 6 minutes and 26 seconds.^[15]

The cruise ship Costa Classica was chartered specifically to view this eclipse and by viewing the eclipse at the point of maximum duration and cruising along the centerline during the event, duration was extended to 6 minutes, 42 seconds.

The eclipse was part of Saros series 136, descending node, as was the solar eclipse of July 11, 1991, which was slightly longer, lasting up to 6 minutes 53.08 seconds (previous eclipses of the same saros series on June 30, 1973, and June 20, 1955, were longer, lasting 7 min 03.55 and 7 min 07.74, respectively). The next event from this series will be on August 2, 2027 (6 minutes and 22.64 seconds).^[16] The exceptional duration was a result of the Moon being near perigee, with the apparent diameter of the Moon 7.991% larger than the Sun (magnitude 1.07991) and the Earth being near aphelion^[17] where the Sun appeared slightly smaller.

In contrast the annular solar eclipse of January 26, 2009 (Saros 131, ascending node) occurred 3.3 days after lunar apogee and 7.175% smaller apparent diameter to the sun. And the next solar eclipse of January 15, 2010 (Saros 141, ascending node) was also annular, 1.8 days before lunar apogee, with the Moon 8.097% smaller than the Sun.

The Terrain Mapping Camera in the Chandrayaan-1 lunar mission was used to image the earth during the eclipse.^[18]

It was also observed by the Japanese geostationary satellite MTSAT:^[19]