Sky watchers in every continent but Australia reveled in the relative rarity of a total lunar eclipse Saturday night — but as stargazers have noted for centuries, it was a matter of celestial perspective. “From the moon, they’re having a solar eclipse,” said Dean Regas, an astronomer at the Cincinnati Observatory Center.
A lunar eclipse occurs when the moon, Earth and sun are in alignment and the moon passes through the planet’s shadow. In a solar eclipse, an area of Earth is in the moon’s shadow.
The Cincinnati Observatory, which claims to be the oldest in the United States, was founded in 1842 and has been in its current location on the city’s east side since 1871.
It had one of its biggest nights ever Saturday, as officials estimated about 800 people stood in line for a chance to peer through the observatory’s telescope.
Outside, amateur astronomers set up telescopes on one of the city’s highest promontories. Bill Lewis, a 53-year old computer programmer from suburban Montgomery, declared the viewing a success.
“It’s a good one, because the sky is so clear,” he said, adjusting the focus on his new $500 rig. “I thought there would be about 10 of us crazies out here, but look at the crowd.”
Earth’s shadow started creeping over the lunar disk at about 5:15 p.m. ET, and the event reached its peak a few minutes after 8 p.m. when the shadow engulfed the moon.
Total lunar eclipses can range in color — from dark brown and red to bright orange, yellow and even gray — depending on how much dust and clouds are in Earth’s atmosphere. Saturday night’s eclipse appeared light red to many people and brownish or gray to others.
Residents of the eastern United States could view the eclipse from beginning to end, but it was already under way when the moon rose around sunset in the West. The total phase ended a few minutes after 8:30 p.m. ET, and by 10:30 p.m. the show was over.
Saturday night’s event was an encore of sorts: A total lunar eclipse in May was also visible from North America.
Lunar eclipses are expected on May 4 and Oct. 28 next year. North America will be totally shut out from seeing May’s eclipse, but October’s total phase can be seen from parts of North America as well as Europe and all of South America.
The stages of the eclipse
1. Moon enters penumbra (5:15 p.m. ET): Earth’s shadow cone has two parts: a dark, inner umbra, surrounding by a lighter penumbra. The penumbra is the pale outer portion of the Earth’s shadow.
Although the start of the moon’s passage into the penumbra marked the official onset of the eclipse, this was in essence an academic event, with no perceptible effect.
2. Penumbral shadow appears (6:14 p.m. ET): The moon progressed far enough into the penumbra that the shadow became evident on the moon’s disk.
3. Moon enters umbra (6:33 p.m. ET): The moon began to cross into Earth’s dark central shadow, called the umbra. A small dark scallop started to appear on the moon’s left-hand limb.
4. 75 percent coverage (7:43 p.m. ET): With three-quarters of the moon’s disk eclipsed, that part of it that was immersed in shadow began to very faintly light up, similar to a piece of iron heated to the point where it just begins to glow.
5. Less than five minutes to totality (8:01 p.m. ET): Several minutes before (and after) totality, the contrast between the remaining pale-yellow sliver and the ruddy-brown coloration spread over the rest of the moon’s disk produced a phenomenon known to some as the “Japanese Lantern Effect.”
6. Total eclipse begins (8:06 p.m. ET): When the last of the moon entered the umbra, the total eclipse began.
7. Middle of totality (8:19 p.m. ET): The moon was shining from 10,000 to 100,000 times fainter than it was just a couple of hours earlier.
8. Total eclipse ends (8:31 p.m. ET): The emergence of the moon from the shadow began. The first small segment of the moon began to reappear, followed again for several minutes by the Japanese Lantern Effect.
9. 75 percent coverage (8:55 p.m. ET ): Any vestiges of coloration within the umbra started disappearing.
10. Moon leaves umbra (10:05 p.m. ET): The dark central shadow cleared the moon’s right-hand limb.
11. Penumbra shadow fades away (10:24 p.m. ET): As the last, faint shading vanished off the moon’s right portion, the visual show came to an end.
12. Moon leaves penumbra (11:22 p.m. ET): The eclipse “officially” ends, as it is completely free of the penumbral shadow.
Space.com and The Associated Press contributed to this report.