NASA retired eclipse scientist Fred Espenac has been monitoring the night sky since he was eight years old and plans to once again search for the impending lunar eclipse on Sunday (May 15th).
After nearly six decades looking at the sky, the Arizona resident said he still likes to watch the eclipse shift as the moon turns red during a total lunar eclipse, going completely into the deepest shadow of the Earth. Read our complete guide to the Super Flower Blood Moon eclipse to prepare for the epic lunar event.
Webcasts: How to watch the Super Flower Blood Moon lunar eclipse online
“You look at it 10 seconds before or 10 seconds after, you can not tell the difference,” Espenak told Space.com about the lunar eclipses. “It is more of a gradual result. From minute to minute you can see changes, but from second to second you can not.”
The lunar eclipse will be fully visible from parts of the Americas, Antarctica, Europe, Africa and the eastern Pacific. This eclipse will have a moon that looks slightly larger, on the edge of the state of the supermoon. If you are hoping to photograph the moon or want to prepare your equipment for a total lunar eclipse, check out our best astrophotography cameras and the best astrophotography lenses. Read our guides on how to photograph a lunar eclipse, as well as how to photograph the moon with a camera for some useful tips to plan your lunar photography.
Not everyone agrees that the full moon of flowers is a supermoon due to different definitions. Espenak’s definition is based on the first full moon, when astrologer Richard Nolle in 1979 defined it as a full moon within 90% of its closest point in Earth orbit.
“That’s the definition I use, because that’s the first one. As far as I’m concerned, that’s the former,” he said. “But first of all, this 90% is purely arbitrary. There is no real justification why it should be 90%, or 89 or 91.”
But Espenak calculates the supermoon to take into account changes in the moon’s orbit during each lunar cycle, including the periphery (nearest point) and the apogee (the farthest point). NASA, which follows the strict definition of 90%, says that the Flower Moon is not a supermoon, but that the full moon of June will be.
Espenak’s logic ends with lunar variability. “The periphery and the apogee of everyone [moon] “The trajectory varies from one orbit to another,” he said. This is because the Earth and the gravity of the sun pull the moon into its orbits.
“The limits of what you get as a supermoon vary from one orbit to another,” he added. “Well, to determine if a particular moon is a supermoon or not, you have to look at that particular lunar orbit during that lunar cycle.” (Lunation is a lunar month or the time between the new moons.)
Epsenak’s definition of a supermoon will put the next four full moons in a row as a supermoon: May 16, June 14, July 13 and August 12. However, he noted that the series is not particularly unusual. According to its website, 2023 will also see four consecutive full moons, as well as 2024. Even 2025 has three in a row.
“Every 14 months or so, you receive a series of moons that are beyond this 90% limit. So very often, every 14 months or so, we have two or more likely three to four,” he explained. He added that the relative size of the largest full moon is so small, however, that even he can not easily distinguish the difference by looking only at the sky.
While the size of the crescent moon will be discreet, the eclipse will become quite interesting as soon as it reaches its first smooth contact with the moon. A half-light or light eclipse introduces subtle shading, but the umbrella, Espenak said, will “look like the cookie monster has pulled a piece” from the moon.
“One does not really see the color until it is close to the whole,” he said. Blood Moon, he added, should be very easy to spot within minutes of the whole, although this will depend on the lighting and weather conditions in your area.
“In dark places, it is easier to detect discreet colors and features,” he said. “Observers with sharp eyes will notice that the part of the moon that is deep in the shadow will be able to see some color in it in the last five to ten minutes of some phases as we approach the whole.”
Blood Moon, however, may not look exactly red. “It ranges from bright orange, in a red fire truck, to dark brown, to an almost invisible dark brown-gray,” Espenak said. “Most of the time, however, it is orange to red, and this is due to the colors caused by the sunlight that filters the Earth’s atmosphere.”
While time depends on your location, TimeandDate.com says that the partial lunar eclipse phase begins on May 15 at 22:28 EDT (0228 GMT on May 16). It will reach the climax of Blood Moon in red on May 16 at 12:11 p.m. EDT (0411 GMT). The event ends at 1:55 a.m. EDT (0555 GMT). Note that the partial eclipse will start about an hour earlier and end approximately one hour after the partial eclipse.
Author’s note: If you take an amazing lunar eclipse photo (or your own webcast) and want to share it with Space.com readers, send your photos, comments, and your name and location to email@example.com .