| Partial eclipse | |
 Map | |
| Gamma | −1.1081 |
|---|---|
| Magnitude | 0.7883 |
| Maximum eclipse | |
| Coordinates | 71°54′S23°18′E / 71.9°S 23.3°E /-71.9; 23.3 |
| Times (UTC) | |
| Greatest eclipse | 15:03:47 |
| References | |
| Saros | 148 (19 of 75) |
| Catalog # (SE5000) | 9460 |
A partialsolar eclipse occurred at the Moon'sdescending node of orbit on Friday, April 7, 1978,[1] with amagnitude of 0.7883. Asolar eclipse occurs when theMoon passes betweenEarth and theSun, thereby totally or partly obscuring the image of the Sun for a viewer on Earth. A partial solar eclipse occurs in the polar regions of the Earth when the center of the Moon's shadow misses the Earth.
A partial eclipse was visible for parts ofAntarctica, southernSouth America, andSouthern Africa.
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.[2]
| Event | Time (UTC) |
|---|---|
| First Penumbral External Contact | 1978 April 7 at 13:02:42.8 UTC |
| Equatorial Conjunction | 1978 April 7 at 14:26:21.8 UTC |
| Greatest Eclipse | 1978 April 7 at 15:03:46.6 UTC |
| Ecliptic Conjunction | 1978 April 7 at 15:15:57.9 UTC |
| Last Penumbral External Contact | 1978 April 7 at 17:05:13.3 UTC |
| Parameter | Value |
|---|---|
| Eclipse Magnitude | 0.78828 |
| Eclipse Obscuration | 0.72528 |
| Gamma | −1.10812 |
| Sun Right Ascension | 01h04m17.8s |
| Sun Declination | +06°50'43.3" |
| Sun Semi-Diameter | 15'58.5" |
| Sun Equatorial Horizontal Parallax | 08.8" |
| Moon Right Ascension | 01h05m31.3s |
| Moon Declination | +05°50'22.8" |
| Moon Semi-Diameter | 15'32.4" |
| Moon Equatorial Horizontal Parallax | 0°57'02.1" |
| ΔT | 48.8 s |
This eclipse is part of aneclipse 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 afortnight.
| March 24 Ascending node (full moon) | April 7 Descending node (new moon) |
|---|---|
 | |
| Total lunar eclipse Lunar Saros 122 | Partial solar eclipse Solar Saros 148 |
This eclipse is a member of asemester series. An eclipse in a semester series of solar eclipses repeats approximately every 177 days and 4 hours (a semester) at alternatingnodes of the Moon's orbit.[3]
| Solar eclipse series sets from 1975 to 1978 | ||||||
|---|---|---|---|---|---|---|
| Descending node | Ascending node | |||||
| Saros | Map | Gamma | Saros | Map | Gamma | |
| 118 | May 11, 1975 Partial | 1.0647 | 123 | November 3, 1975 Partial | −1.0248 | |
| 128 | April 29, 1976 Annular | 0.3378 | 133 | October 23, 1976 Total | −0.327 | |
| 138 | April 18, 1977 Annular | −0.399 | 143 | October 12, 1977 Total | 0.3836 | |
| 148 | April 7, 1978 Partial | −1.1081 | 153 | October 2, 1978 Partial | 1.1616 | |
This eclipse is a part ofSaros series 148, repeating every 18 years, 11 days, and containing 75 events. The series started with a partial solar eclipse on September 21, 1653. It contains annular eclipses onApril 29, 2014 andMay 9, 2032; a hybrid eclipse onMay 20, 2050; and total eclipses fromMay 31, 2068 through August 3, 2771. The series ends at member 75 as a partial eclipse on December 12, 2987. Its eclipses are tabulated in three columns; every third eclipse in the same column is oneexeligmos apart, so they all cast shadows over approximately the same parts of the Earth.
The longest duration of annularity will be produced by member 22 at 22 seconds (by default) onMay 9, 2032, and the longest duration of totality will be produced by member 54 at 5 minutes, 23 seconds on April 26, 2609. All eclipses in this series occur at the Moon’sdescending node of orbit.[4]
| Series members 10–31 occur between 1801 and 2200: | ||
|---|---|---|
| 10 | 11 | 12 |
 December 30, 1815 |  January 9, 1834 |  January 21, 1852 |
| 13 | 14 | 15 |
 January 31, 1870 |  February 11, 1888 |  February 23, 1906 |
| 16 | 17 | 18 |
 March 5, 1924 |  March 16, 1942 |  March 27, 1960 |
| 19 | 20 | 21 |
April 7, 1978 |  April 17, 1996 |  April 29, 2014 |
| 22 | 23 | 24 |
 May 9, 2032 |  May 20, 2050 |  May 31, 2068 |
| 25 | 26 | 27 |
 June 11, 2086 |  June 22, 2104 |  July 4, 2122 |
| 28 | 29 | 30 |
 July 14, 2140 |  July 25, 2158 |  August 4, 2176 |
| 31 | ||
 August 16, 2194 | ||
Themetonic 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 April 8, 1902 and August 31, 1989 | ||||
|---|---|---|---|---|
| April 7–8 | January 24–25 | November 12 | August 31–September 1 | June 19–20 |
| 108 | 110 | 112 | 114 | 116 |
 April 8, 1902 |  August 31, 1913 |  June 19, 1917 | ||
| 118 | 120 | 122 | 124 | 126 |
 April 8, 1921 |  January 24, 1925 |  November 12, 1928 |  August 31, 1932 |  June 19, 1936 |
| 128 | 130 | 132 | 134 | 136 |
 April 7, 1940 |  January 25, 1944 |  November 12, 1947 |  September 1, 1951 |  June 20, 1955 |
| 138 | 140 | 142 | 144 | 146 |
 April 8, 1959 |  January 25, 1963 |  November 12, 1966 |  August 31, 1970 |  June 20, 1974 |
| 148 | 150 | 152 | 154 | |
April 7, 1978 |  January 25, 1982 |  November 12, 1985 |  August 31, 1989 | |
This eclipse is a part of atritos cycle, repeating at alternating nodes every 135synodic months (≈ 3986.63 days, or 11 years minus 1 month). Their appearance and longitude are irregular due to a lack of synchronization with theanomalistic 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 1801 and 2087 | ||||
|---|---|---|---|---|
 August 17, 1803 (Saros 132) |  July 17, 1814 (Saros 133) |  June 16, 1825 (Saros 134) |  May 15, 1836 (Saros 135) |  April 15, 1847 (Saros 136) |
 March 15, 1858 (Saros 137) |  February 11, 1869 (Saros 138) |  January 11, 1880 (Saros 139) |  December 12, 1890 (Saros 140) |  November 11, 1901 (Saros 141) |
 October 10, 1912 (Saros 142) |  September 10, 1923 (Saros 143) |  August 10, 1934 (Saros 144) |  July 9, 1945 (Saros 145) |  June 8, 1956 (Saros 146) |
 May 9, 1967 (Saros 147) | April 7, 1978 (Saros 148) |  March 7, 1989 (Saros 149) |  February 5, 2000 (Saros 150) |  January 4, 2011 (Saros 151) |
 December 4, 2021 (Saros 152) |  November 3, 2032 (Saros 153) |  October 3, 2043 (Saros 154) |  September 2, 2054 (Saros 155) |  August 2, 2065 (Saros 156) |
 July 1, 2076 (Saros 157) |  June 1, 2087 (Saros 158) | |||
This eclipse is a part of the long periodinex cycle, repeating at alternating nodes, every 358synodic months (≈ 10,571.95 days, or 29 years minus 20 days). Their appearance and longitude are irregular due to a lack of synchronization with theanomalistic 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.
| Series members between 1801 and 2200 | ||
|---|---|---|
 August 5, 1804 (Saros 142) |  July 17, 1833 (Saros 143) |  June 27, 1862 (Saros 144) |
 June 6, 1891 (Saros 145) |  May 18, 1920 (Saros 146) |  April 28, 1949 (Saros 147) |
April 7, 1978 (Saros 148) |  March 19, 2007 (Saros 149) |  February 27, 2036 (Saros 150) |
 February 5, 2065 (Saros 151) |  January 16, 2094 (Saros 152) |  December 28, 2122 (Saros 153) |
 December 8, 2151 (Saros 154) |  November 17, 2180 (Saros 155) | |
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