Solar eclipse of February 4, 1981

44°24′S 140°48′W / 44.4°S 140.8°W / -44.4; -140.8Max. width of band25 km (16 mi)Times (UTC)Greatest eclipse22:09:24ReferencesSaros140 (27 of 71)Catalog # (SE5000)9466

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 5 (Thursday), and ended at sunset over western South America on February 4 (Wednesday). Occurring only 4 days before perigee (Perigee on February 8, 1981), the moon's apparent diameter was larger.

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

More details about the Annular Solar Eclipse of 1981 Feb 04.

Eclipse Magnitude = 0.99375 (99.375%) Eclipse Obscuration = 0.98754 (98.754%) Greatest Eclipse = 1981 Feb 04 at 22:09:23.5 TD (22:08:32.1 UTC) Ecliptic Conjunction = 1981 Feb 04 at 22:14:36.9 TD (22:13:45.5 UTC) Equatorial Conjunction 1981 Feb 04 at 21:58:30.2 TD (21:57:38.8 UTC) Gamma = -0.48375 (48.511%) Sun's Right Ascension = 21.232 Sun's Declination = -16.03º Sun's Diameter = 1946.4 arcseconds Moon's Right Ascension = 21.239 Moon's Declination = -16.49º Moon's Diameter = 1907.2 arcseconds Moon's Distance = 375948.60 km (233603.63 mi)

Related eclipses

Eclipses in 1981

• A penumbral lunar eclipse on Tuesday, 20 January 1981.
• An annular solar eclipse on Wednesday, 4 February 1981.
• A partial lunar eclipse on Friday, 17 July 1981.
• A total solar eclipse on Friday, 31 July 1981.

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).

Solar eclipse series sets from 1979 to 1982
Descending node				Ascending node
Saros	Map	Gamma		Saros	Map	Gamma
120	1979 February 26 Total	0.89811		125	1979 August 22 Annular	−0.96319
130	1980 February 16 Total	0.22244		135	1980 August 10 Annular	−0.19154
140	1981 February 4 Annular	−0.48375		145	1981 July 31 Total	0.57917
150	1982 January 25 Partial	−1.23110		155	1982 July 20 Partial	1.28859
Partial solar eclipses on June 21, 1982 and December 15, 1982 occur in the next lunar year eclipse set.

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.

Series members 23–53 occur between 1901 and 2450:
23	24	25
Dec 23, 1908	Jan 3, 1927	Jan 14, 1945
26	27	28
Jan 25, 1963	Feb 4, 1981	Feb 16, 1999
29	30	31
Feb 26, 2017	Mar 9, 2035	Mar 20, 2053
32	33	34
Mar 31, 2071	Apr 10, 2089	Apr 23, 2107
35	36	37
May 3, 2125	May 14, 2143	May 25, 2161
38	39	40
Jun 5, 2179	Jun 15, 2197	Jun 28, 2215
41	42	43
Jul 8, 2233	Jul 19, 2251	Jul 29, 2269
44	45	46
Aug 10, 2287	Aug 21, 2305	Sep 1, 2323
47	48	49
Sep 12, 2341	Sep 23, 2359	Oct 3, 2377
50	51	52
Oct 14, 2395	Oct 25, 2413	Nov 5, 2431
53
Nov 15, 2449

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.

Series members between 1901 and 2100
September 9, 1904 (Saros 133)	August 10, 1915 (Saros 134)	July 9, 1926 (Saros 135)
June 8, 1937 (Saros 136)	May 9, 1948 (Saros 137)	April 8, 1959 (Saros 138)
March 7, 1970 (Saros 139)	February 4, 1981 (Saros 140)	January 4, 1992 (Saros 141)
December 4, 2002 (Saros 142)	November 3, 2013 (Saros 143)	October 2, 2024 (Saros 144)
September 2, 2035 (Saros 145)	August 2, 2046 (Saros 146)	July 1, 2057 (Saros 147)
May 31, 2068 (Saros 148)	May 1, 2079 (Saros 149)	March 31, 2090 (Saros 150)

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.

22 eclipse events between September 12, 1931 and July 1, 2011.
September 11-12	June 30-July 1	April 17-19	February 4-5	November 22-23
114	116	118	120	122
September 12, 1931	June 30, 1935	April 19, 1939	February 4, 1943	November 23, 1946
124	126	128	130	132
September 12, 1950	June 30, 1954	April 19, 1958	February 5, 1962	November 23, 1965
134	136	138	140	142
September 11, 1969	June 30, 1973	April 18, 1977	February 4, 1981	November 22, 1984
144	146	148	150	152
September 11, 1988	June 30, 1992	April 17, 1996	February 5, 2000	November 23, 2003
154	156
September 11, 2007	July 1, 2011

Notes

References

• Earth visibility chart and eclipse statistics Eclipse Predictions by Fred Espenak, NASA/GSFC
  • Google interactive map
  • Besselian elements
• Annular Solar Eclipse Observed for Solar Radius Determination Observed from Tasmania, by Fiala, A. D., Herald, D., & Dunham, D. W, Bulletin of the American Astronomical Society, Vol. 13, p. 552
• Correcting predictions of solar eclipse contact times for the effects of lunar limb irregularities Observations from Tasmania by Herald, D. Journal of the British Astronomical Association, vol.93, no.6, p. 241–246