Don’t miss one of the top astronomical events for 2022: Sunday night’s total lunar eclipse.

The first eclipse season of 2022 reaches its climax this coming weekend, with a fine total lunar eclipse transpiring on Sunday night into Monday morning. All of South America and most of North America will see the eclipse in its entirety, while Alaska and western Canada will see totality underway at moonrise, and western Europe will see the reverse at moonset near dawn.

The Circumstances for Sunday Night’s Eclipse

Eclipses occur when the nodes where the Moon’s orbit intersect the ecliptic (the plane traced out by the orbit of the Earth) align with the Sun and the Earth, in what’s known as a syzygy. The Moon’s orbit is tilted just over five degrees relative to the ecliptic—otherwise, we’d see solar and lunar eclipses every synodic month (29.5 days). When the nodes are near the Sun-Earth line, an eclipse season occurs. For example, this first season of 2022 was bracketed by the April 30th partial solar eclipse, followed by this coming weekend’s lunar eclipse.

Circumstances for Sunday Night

The Earth’s dark inner umbral shadow is about three times the diameter of the Moon (1.5 degrees across) at the Moon’s average distance from the Earth. You can actually see the curve of the spherical Earth’s shadow crossing the Moon during an eclipse, no special gear needed.

Shadows also have a more subtle penumbral outer edge, inside which the light source is partially visible. From the Earthward surface of the Moon, you’d see a partial solar eclipse during the penumbral phases, and a total solar eclipse during the umbral stage. NASA’s Surveyor 3 did actually manage to grab an image of a solar eclipse from the Moon in 1967:

A solar eclipse… seen from the Moon. Credit: NASA/Surveyor 3

Perhaps, human eyes could repeat this feat as the Artemis missions return crew to the lunar surface, starting mid-decade.

Sunday night’s eclipse… as seen from the Moon. Credit: Stellarium.

Don’t expect to see too much discernible change in the color of the Moon Sunday night until it’s about mid-way immersed in the penumbra around 10:00 PM Eastern Time (EDT)/2:00 Universal Time (UT). Then, the Moon will take on a light tea-colored hue. Around 2:20 UT, you will note a shading on the eastern limb of the Moon, as it nears the umbra and the partial stages begin.

Timing and visibility circumstances for Sunday night’s eclipse. Credit: NASA/GSFC/Annotations: Dave Dickinson

The key time is totality, and will be a long one for this eclipse, clocking in at 1 hours, 24 minutes and 53 seconds in duration. Totality runs from3:29 UT/11:29 PM EDT to 4:54 UT/12:54 PM EDT, making it the 5th longest lunar eclipse for the first quarter of the 21st century.

This is not a ‘Super Blood Moon Eclipse…’ though no doubt folks will try to bill it as such. The eclipse actually occurs about a day and a half prior to lunar perigee on May 17th at 15:24 UT, when the Moon is 360,300 kilometers distant.

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