A total solar eclipse occurred at the Moon's ascending node of orbit on Saturday, March 7, 1970,[1][2][3][4][5][6] with a magnitude of 1.0414. A solar eclipse occurs when the Moon passes between Earth and the Sun, thereby totally or partly obscuring the image 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 darkness. 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 1.3 days after perigee (on March 6, 1970, at 10:30 UTC), this eclipse occurred when the Moon's apparent diameter was larger.[7]
The greatest eclipse occurred over Mexico at 11:38 am CST, with totality lasting 3 minutes and 27.65 seconds. Totality over the U.S. lasted up to 3 minutes and 10 seconds.[8] The media declared Perry as the first municipality in Florida to be in the eclipse direct path.
Inclement weather obstructed the viewing from that location and most of the eclipse path through the remainder of the southern states. There was not an eclipse with a greater duration of totality over the contiguous U.S. until April 8, 2024, a period of 54 years.
An observation team from the Swiss Federal Observatory observed the total eclipse in Nejapa and Miahuatlán, Mexico. The weather conditions were good at both locations. Miahuatlán offered particularly good observation conditions with an altitude of 1,620 metres above sea level, high air quality and solar zenith angle of 63° at the time of the eclipse. The team took images of the corona and analyzed them with a polarizing filter.[11] Austrian-American physicist Erwin Saxl and American physicist Mildred Allen reported anomalous changes in the period of a torsion pendulum when observing a partial solar eclipse with a magnitude of 0.954 from Harvard, Massachusetts, called the "Saxl Effect".[12]
Visible Planets and Stars
During totality, other celestial objects brighter than magnitude 1.5 often become visible. By far the brightest and therefore easiest object seen around totality on 7/3/1970 was Venus, which lay about an hour east of the eclipsed Sun. Mars and Saturn were about three hours east of the Sun with Saturn the brighter planet, while Mercury, 16 days away from superior conjunction (and therefore showing most of its sunlit side, making it bright), was an hour or so west of the Sun.[13] Of the stars, Fomalhaut was almost due south of the Sun, the Summer Triangle of Vega, Deneb and Altair was well up in the west, and recently risen Aldebaran and Capella were in the east and northeast respectively.[14]
This eclipse might be referenced in the second episode of the first season of The Mary Tyler Moore Show when a guest of Mary's accidentally exposes a roll of film that Howard Arnell, an ex-boyfriend of Mary's, says, "It's just the pictures I took of the total eclipse of the sun."
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.[25]
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.[26]
The partial solar eclipse on July 22, 1971 occurs in the next lunar year eclipse set.
This eclipse is a part of Saros series 139, repeating every 18 years, 11 days, and containing 71 events. The series started with a partial solar eclipse on May 17, 1501. It contains hybrid eclipses from August 11, 1627 through December 9, 1825 and total eclipses from December 21, 1843 through March 26, 2601. There are no annular eclipses in this set. The series ends at member 71 as a partial eclipse on July 3, 2763. 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 totality will be produced by member 61 at 7 minutes, 29.22 seconds on July 16, 2186. This date is the longest solar eclipse computed between 4000 BC and AD 6000.[27] All eclipses in this series occur at the Moon’s ascending node of orbit.[28]
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 December 24, 1916 and July 31, 2000
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.
↑Sadeh, D. (1971), Phase variation of a very accurate radio frequency signal due to the solar eclipse, J. Geophys. Res., 76(34), 8427–8429, doi:10.1029/JA076i034p08427
↑"You're So Vain by Carly Simon". Songfacts. Retrieved 2024-12-01. Glenn A. Walsh, who was Astronomical Observatory Coordinator and a Planetarium Lecturer for Pittsburgh's original Buhl Planetarium, told us: ... In fact, one day in mid-June of 1972, a colleague and I were in the radio station when the record was played. When that particular lyric was heard, he turned to me and said, 'that would be nice.' I knew he meant that it would be nice to fly to Nova Scotia and see the eclipse the next month.