Why Does a Lunar Eclipse Have Two Dates?
The date of a lunar eclipse depends on where you are in the world.
Same Moment, Different Local Times
Nevertheless, because observers are spread out across different time zones, their local times vary.
’Round Midnight, Before Dawn, and After Dusk
Our streaming partners in Hawaii were close to the point on the globe where the Moon was directly overhead at maximum eclipse. Here, the entire event was visible; it began before midnight, and ended after midnight:
- Beginning: 20:02 (Nov 18)
- Maximum: 23:02 (Nov 18)
- End: 02:03 (Nov 19)
If we jump to the east—to our streaming partner in New York—the event began after midnight, and ended when the Moon set at dawn:
- Beginning: 01:02 (Nov 19)
- Maximum: 04:02 (Nov 19)
- End (moonset): 06:57 (Nov 19)
If we jump to the west from Hawaii—to the Australian city of Sydney—the event began at dusk when the Moon rose, and ended before midnight. However, because we’ve crossed the International Date Line, this was the evening of the following day:
- Beginning (moonrise): 19:34 (Nov 19)
- Maximum: 20:02 (Nov 19)
- End: 23:03 pm (Nov 19)
Fun fact: Not so long from now, there will be a total lunar eclipse that runs from one year into the next...