Solar eclipse of July 22, 2009

Visibility

A partial eclipse was seen within the broad path of the Moon's penumbra, including most of Southeast Asia (all of 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 northern part of the Ryukyu Islands, Marshall Islands, and Kiribati.

Totality was visible in many large cities, including Dhaka, Surat, Vadodara, Bhopal, Varanasi, Patna, Gaya, Dinajpur, Siliguri, Guwahati, Tawang in India and Chengdu, Nanchong, Chongqing, Yichang, Jingzhou, Wuhan, Huanggang, Hefei, Hangzhou, Wuxi, Huzhou, Suzhou, Jiaxing, Ningbo, Shanghai, Chapai Nawabganj 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. According to NASA, the Japanese island Kitaio Jima was predicted to have the best viewing conditions 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.

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

Observations

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.

Indian scientists observed the solar eclipse from an Indian Air Force plane.

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.

Duration

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. Totality lasted for up to 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.

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, as was the solar eclipse of July 11, 1991, which was slightly longer, lasting up to 6 minutes 53 seconds (previous eclipses of the same saros series on June 30, 1973 and June 20, 1955, were longer, lasting 7 min 04 and 7 min 08, respectively). The next event from this series will be on August 2, 2027. The exceptional duration was a result of the Moon being near perigee, with the apparent diameter of the Moon 8% larger than the Sun (magnitude 1.080) and the Earth being near aphelion where the Sun appeared slightly smaller.

In contrast the annular solar eclipse of January 26, 2009 occurred near lunar apogee and 7% smaller apparent diameter to the sun. And the next solar eclipse of January 15, 2010 was also annular, with the Moon 8.1% smaller than the Sun.

View from space

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

It was also observed by the Japanese geostationary satellite MTSAT:

Related eclipses

This total eclipse the second in the series of three eclipses in a one-month period, with two minor penumbral lunar eclipses, first on July 7 and last on August 6.

Solar eclipses 2008–2011

Each member in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternating nodes of the Moon's orbit.

Saros series

Solar Saros 136, repeating every 18 years, 11 days, contains 71 events. The series started with partial solar eclipse on Jun 14, 1360, and reached a first annular eclipse on September 8, 1504. It was a hybrid event from November 22, 1612, through January 17, 1703, and total eclipses from January 27, 1721 through May 13, 2496. The series ends at member 71 as a partial eclipse on July 30, 2622, with the entire series lasting 1262 years. The longest eclipse occurred on June 20, 1955, with a maximum duration of totality at 7 minutes, 8 seconds.

Metonic cycle

The metonic series repeats eclipses every 19 years (6939.69 days), lasting about 5 cycles. Eclipses occur in nearly the same calendar date. In addition the octon subseries repeats 1/5 of that or every 3.8 years (1387.94 days).