October 1939 lunar eclipse
| Partial eclipse | |||||||||||||
The Moon's hourly motion shown right to left | |||||||||||||
| Date | October 28, 1939 | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Gamma | −0.4581 | ||||||||||||
| Magnitude | 0.9876 | ||||||||||||
| Saros cycle | 135 (19 of 71) | ||||||||||||
| Partiality | 203 minutes, 22 seconds | ||||||||||||
| Penumbral | 346 minutes, 5 seconds | ||||||||||||
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A partial lunar eclipse occurred at the Moon’s descending node of orbit on Saturday, October 28, 1939, with an umbral magnitude of 0.9876. A lunar eclipse occurs when the Moon moves into the Earth's shadow, causing the Moon to be darkened. A partial lunar eclipse occurs when one part of the Moon is in the Earth's umbra, while the other part is in the Earth's penumbra. 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. Occurring about 5.3 days after apogee (on October 23, 1939, at 0:05 UTC), the Moon's apparent diameter was smaller.
This lunar eclipse was the last of an almost tetrad, with the others being on May 14, 1938 (total); November 7, 1938 (total); and May 3, 1939 (total).
This was the last partial lunar eclipse of the first set of partial eclipses in Lunar Saros 135 as well as the largest partial lunar eclipse of the 20th century.