On Tuesday evening, skywatchers in North America, South America, Europe, and Africa will have the opportunity to witness a rare celestial event: a harvest moon, a blood moon, and a supermoon all happening at the same time.
The simultaneous occurrence of all three celestial events is “quite rare,” according to Teresa Monsue, an astrophysicist at NASA’s Goddard Space Flight Center.
Here’s what you need to know about this celestial trifecta and how to observe it in the U.S.
What is a harvest moon?
The harvest moon appears near the autumn equinox. Its name, according to the Old Farmer’s Almanac, originates from the time when its brightness would assist farmers in harvesting their late-season crops. What makes this event special is the positioning of the moon’s orbit and Earth’s horizon, resulting in the moon appearing to rise above the horizon significantly faster than usual. When viewed shortly after sunset, while the moon is low in the sky, it creates an optical illusion that makes the harvest moon seem larger than usual. This effect will be further magnified by the fact that Tuesday night’s harvest moon will coincide with a supermoon.
What is a supermoon?
Supermoons occur when the moon is both full and at its closest point to Earth, making the moon appear larger than usual. Supermoons happen between three to four times a year due to variations in the moon’s orbit and distance from Earth with each new cycle.
What is a blood moon?
During a lunar eclipse, Earth’s shadow partially obstructs the sun’s light from reaching the moon, giving it a reddish appearance often referred to as a blood moon. On Tuesday night, in addition to observing the characteristics of a harvest and supermoon, stargazers can also anticipate the moon having an unusual red hue due to a partial lunar eclipse taking place simultaneously.
Where and when can I watch the Harvest-Blood-Supermoon?
It’s advantageous to watch from a location with clear skies, which you can check using your local weather app. The Midwest, South, and Southern Plains of the U.S. are expected to have relatively clear skies on Tuesday night, according to AccuWeather. West coast cities like Los Angeles and San Francisco can also expect relatively clear skies. However, on the East Coast, conditions might be more challenging. Cities such as Boston and Washington, D.C. may have cloudier forecasts, making it more difficult to view the event.
The partial lunar eclipse commences at 8:41 p.m. E.T. and reaches its peak at 10:44 p.m., according to NASA, but observers may be able to notice part of the moon entering full shadow as early as 10:13 p.m.
When will be the next Harvest-Blood-Supermoon?
The next Harvest-Blood-Supermoon combination will occur in the fall of 2033, according to the public service radio program StarDate. While it’s a while away, the 2033 moon will be even more rare because it will also include a full lunar eclipse instead of a partial one.
The next full supermoon will be visible on Oct. 17, 2024, and the next lunar eclipse will occur on Mar. 14, 2025, according to NASA.