Solar eclipse of February 4, 1981

An annular solar eclipse occurred at the Moon's descending node of the orbit on February 4–5, 1981. 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. An annular solar eclipse occurs when the Moon's apparent diameter is smaller than the Sun's, blocking most of the Sun's light and causing the Sun to look like an annulus (ring). An annular eclipse appears as a partial eclipse over a region of the Earth thousands of kilometres wide. This annular solar eclipse was large because the Moon covered 99.4% of the Sun, with a path width of only 25 km (15.534 mi, or 82,080.997 feet). It was visible in Australia, crossing over Tasmania and southern Stewart Island of New Zealand near sunrise on February 5th (Thursday), and ended at sunset over western South America on February 4th (Wednesday). Occurring only 4 days before perigee (Perigee on February 8, 1981), the moon's apparent diameter was larger.

Solar eclipse of February 4, 1981
Map
Type of eclipse
NatureAnnular
Gamma-0.4838
Magnitude0.9937
Maximum eclipse
Duration33 sec (0 m 33 s)
Coordinates44.4°S 140.8°W / -44.4; -140.8
Max. width of band25 km (16 mi)
Times (UTC)
Greatest eclipse22:09:24
References
Saros140 (27 of 71)
Catalog # (SE5000)9466

The moon's apparent diameter was 7 arcseconds smaller than the July 31, 1981 total solar eclipse.

Solar eclipses of 1979–1982

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.[1] There were 8 solar eclipses between February 26, 1979 and July 20, 1982. Were there: February 26, 1979 (total solar eclipse, 0.8 days after perigee, 103.9%, 0.89811 gamma, saros 120), August 22, 1979 (small annular solar eclipse, 0.6 days before apogee, 93.3%, -0.96319 gamma, saros 125), February 16, 1980 (total solar eclipse, 1 day before perigee, 104.3%, 0.22244 gamma, saros 130), August 10, 1980 (large annular solar eclipse, 5 days before apogee, 97.3%, -0.19154 gamma, saros 135), February 4, 1981 (large annular solar eclipse, 4 days before perigee, 99.4%, -0.48375 gamma, saros 140), July 31, 1981 (total solar eclipse, 3.8 days after perigee, 102.6%, 0.57917 gamma, saros 145), January 25, 1982 (moderate partial solar eclipse, 4.7 days after apogee, 56.6%, -1.23110 gamma, saros 150) and July 20, 1982 (small partial solar eclipse, 0.9 days after perigee, 46.4%, 1.28859 gamma, saros 155).

Saros 140

It is a part of Saros cycle 140, repeating every 18 years, 11 days, containing 71 events. The series started with partial solar eclipse on April 16, 1512. It contains total eclipses from July 21, 1656 through November 9, 1836, hybrid eclipses from November 20, 1854 through December 23, 1908, and annular eclipses from January 3, 1927 through December 7, 2485. The series ends at member 71 as a partial eclipse on June 1, 2774. The longest duration of totality was 4 minutes, 10 seconds on August 12, 1692.

Tritos series

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.

Metonic series

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 descending node.

Notes
  1. van Gent, R.H. "Solar- and Lunar-Eclipse Predictions from Antiquity to the Present". A Catalogue of Eclipse Cycles. Utrecht University. Retrieved 6 October 2018.

References
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