A total solar eclipse occurred at the Moon’s ascending node of orbit on Wednesday, August 11, 1999,[1] with a magnitude of 1.0286. A solar eclipse occurs when the Moon passes between the Earth and the Sun, thereby totally or partly obscuring the light of the sun for a viewer on earth. A total solar eclipse occurs when the Moon’s apparent diameter is larger than the Sun’s, blocking all direct sunlight, turning day into night. Totality occurs in a narrow path across Earth’s surface, with the partial solar eclipse visible over a surrounding region thousands of kilometres wide. Occurring about 3.5 days after perigee (on August 8, 1999, at 0:30 UTC), the Moon's apparent diameter was larger.[2]
Because of the high population densities in areas of the path, this was one of the most-viewed total solar eclipses in human history;[6] although some areas in the path of totality (mainly in Western Europe) offered impaired visibility due to adverse weather conditions.
Some of the organized eclipse-watching parties along the path of totality set up video projectors on which people could watch the moon's shadow as it raced towards them.[7] There was substantial coverage on international TV stations of the progress of the eclipse shadow. The moon's shadow was also observed from the Russian Mir space station; during the eclipse, video from Mir was broadcast live on television.
The BBC concentrated its coverage efforts on the first landfall of the shadow across the western end of Cornwall (from St Ives to Lizard), which was packed with an extraordinary number of visitors, although Cornwall did not have nearly as many spectators as expected leading many organised events to host smaller audiences than anticipated. The veteran amateur astronomer, broadcaster and eclipse-watcher Patrick Moore was brought in to head a live programme, but the eclipse was clouded out. BBC One also produced a special version of their Balloon Idents for the event. The BBC did not have a presence at Goonhilly on the Lizard Peninsula, one of the few places in Cornwall where the clouds parted just in time for the total eclipse to be visible. There was extensive cloud in Perranporth which parted just in time, allowing the very large crowd that had filled the beach and hillsides to witness the event.
Some of the best viewing conditions were to be had mid-Channel, where ferries were halted in calm conditions to obtain an excellent view. Hundreds of people who gathered on the island of Alderney also experienced the event.
Also at sea, many of the Fastnet fleet contestants encountered totality crossing the Celtic Sea on their way to the Fastnet Rock.[8]
A gathering of several thousand people at the airport in Soissons, France, which was on the path of totality, were denied all but a few fleeting glimpses of the eclipse through the overcast sky. The clouds cleared completely just a few minutes after the eclipse.
In contrast, the overcast sky in Amiens, France, where thousands had gathered, cleared only minutes before the eclipse began.
Further inland, viewing conditions were also perfect at Vouziers, a French country town gridlocked by Belgian cars from day-visitors. The patchy cloud covering cleared a short time before the shadow arrived. Some photos from Vouziers were used on the subsequent BBC Sky at Night programme.
The San Francisco Exploratorium featured a live webcast from a crowded town square in Amasya, Turkey.
A Bulgarian Air ForceMiG-21 two-seater was used by the Bulgarian Academy of Sciences to study the solar corona. The MiG-21, flying at 1600–1700 km/h (1000 to 1100 mph) (Mach 1.4-1.5) at an altitude of 13,000 metres (43,000 feet), was able to stay in the moon's umbra for 6 minutes. The photographer, an air force pilot, used two film cameras, both fitted with 200 mm lenses and infrared filters, and one Digital8 video camera.
Hungary's most popular tourist destination, Lake Balaton and its surrounding area, fell into the path of the eclipse entirely, which made the area even more popular for the day. The motorway leading to the city was so crowded that many people had to watch the eclipse while caught in a traffic jam.
One French and two British Concordes briefly followed the eclipse with tourists on board.[9]
The BBC was filming one of its episodes for the TV series Airport that day and, during the show, resident press officers Russell Clisby and Steve Meller took photographs of the eclipse at Heathrow Airport, as well as Aeroflot supervisor Jeremy Spake witnessing the eclipse on a special charter flight.
RTS, the national public broadcaster of Serbia, urged people to remain inside, citing dangers to public health. This caused the streets of all Serbian cities, towns and villages to be entirely deserted during the eclipse (97% of Serbs stayed inside), with many opting to watch it on TV instead.[10]
The BMJ, a month after the eclipse, reported only 14 cases of eye damage from improper viewing of the eclipse - a number lower than initially feared. In one of the most serious cases the patient had looked at the sun without eye protection for twenty minutes, but overall the public health campaign had succeeded.[11]
Shown below are two tables displaying details about this particular solar eclipse. The first table outlines times at which the moon's penumbra or umbra attains the specific parameter, and the second table describes various other parameters pertaining to this eclipse.[14]
This eclipse is part of an eclipse season, a period, roughly every six months, when eclipses occur. Only two (or occasionally three) eclipse seasons occur each year, and each season lasts about 35 days and repeats just short of six months (173 days) later; thus two full eclipse seasons always occur each year. Either two or three eclipses happen each eclipse season. In the sequence below, each eclipse is separated by a fortnight.
This eclipse is a member of a semester series. An eclipse 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.[15]
This eclipse is a part of Saros series 145, repeating every 18 years, 11 days, and containing 77 events. The series started with a partial solar eclipse on January 4, 1639. It contains an annular eclipse on June 6, 1891; a hybrid eclipse on June 17, 1909; and total eclipses from June 29, 1927 through September 9, 2648. The series ends at member 77 as a partial eclipse on April 17, 3009. Its eclipses are tabulated in three columns; every third eclipse in the same column is one exeligmos apart, so they all cast shadows over approximately the same parts of the Earth.
The longest duration of annularity was produced by member 15 at 6 seconds (by default) on June 6, 1891, and the longest duration of totality will be produced by member 50 at 7 minutes, 12 seconds on June 25, 2522. All eclipses in this series occur at the Moon’s ascending node of orbit.[16]
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). All eclipses in this table occur at the Moon's ascending node.
22 eclipse events between January 5, 1935 and August 11, 2018
This eclipse is a part of a tritos cycle, repeating at alternating nodes every 135 synodic months (≈ 3986.63 days, or 11 years minus 1 month). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee), but groupings of 3 tritos cycles (≈ 33 years minus 3 months) come close (≈ 434.044 anomalistic months), so eclipses are similar in these groupings.
This eclipse is a part of the long period inex cycle, repeating at alternating nodes, every 358 synodic months (≈ 10,571.95 days, or 29 years minus 20 days). Their appearance and longitude are irregular due to a lack of synchronization with the anomalistic month (period of perigee). However, groupings of 3 inex cycles (≈ 87 years minus 2 months) comes close (≈ 1,151.02 anomalistic months), so eclipses are similar in these groupings.
^Stavinschi, M., National Seminar" The total solar Eclipse of August, 11, 1999. Interdisciplinary approach, Bucharest, October 15, 1998 in: Romanian Astron. J., vol.8, N.2, p.146 (1998)
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