May 1985 lunar eclipse
| Total eclipse | |||||||||||||||||
The Moon's hourly motion shown right to left | |||||||||||||||||
| Date | May 4, 1985 | ||||||||||||||||
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| Gamma | 0.3520 | ||||||||||||||||
| Magnitude | 1.2369 | ||||||||||||||||
| Saros cycle | 121 (54 of 84) | ||||||||||||||||
| Totality | 67 minutes, 41 seconds | ||||||||||||||||
| Partiality | 198 minutes, 56 seconds | ||||||||||||||||
| Penumbral | 310 minutes, 14 seconds | ||||||||||||||||
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A total lunar eclipse occurred at the Moon’s descending node of orbit on Saturday, May 4, 1985, with an umbral magnitude of 1.2369. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A total lunar eclipse occurs when the Moon's near side entirely passes into the Earth's umbral shadow. Unlike a solar eclipse, which can only be viewed from a relatively small area of the world, a lunar eclipse may be viewed from anywhere on the night side of Earth. A total lunar eclipse can last up to nearly two hours, while a total solar eclipse lasts only a few minutes at any given place, because the Moon's shadow is smaller. Occurring only about 13.5 hours after perigee (on May 4, 1985, at 6:20 UTC), the Moon's apparent diameter was larger.
This lunar eclipse was the first of a tetrad, with four total lunar eclipses in series, the others being on October 28, 1985; April 24, 1986; and October 17, 1986.