We’re getting a total lunar eclipse on Sunday, May 15th at a convenient time of night. It’s especially appealing because for the past few years all lunar eclipses have been penumbral. This means the Moon has repeatedly failed to touch even the outer edge of Earth’s dark shadow and there was thus nothing to see. But the Sunday night mid-month eclipse will make up for it.
Much more about that next week. For now, let’s explore the difference between lunar and solar eclipses, since we will also get a total solar eclipse less than two years from now, which will be the nearest to us for the next 45 years.
Confusing lunar with solar eclipses is a common error. As the photo on this page shows, in 2017 the National Weather Service kept a long-running image on their website that bizarrely showed a lunar eclipse during the month preceding the great, rare, US total solar eclipse. The distinction isn’t a minor geeky thing; there’s an oceanic disparity in terms of spectacle.
Basic stuff first. In a lunar eclipse the Moon goes into the Earth’s shadow. In a solar eclipse the Moon glides in front of the Sun. So a lunar eclipse happens at night, with the Moon changing its appearance. A solar eclipse is a daytime affair, with the Sun being blocked and eye protection needed for everything but the few minutes of totality. If the eclipse is indeed total, then the lunar variety has the full Moon turning a deep coppery orange for about an hour. But beyond that, nothing else happens during a lunar totality. In terms of visual spectacle, this month’s event will look every bit as strange and worthwhile when the Moon is 90% eclipsed at 11:15 p.m. as when it is totally eclipsed at 11:30 p.m.
Another big difference is that a lunar eclipse is seen everywhere the Moon is in the sky at that time, which is half of Earth. This makes eclipses of the Moon sufficiently common that almost everyone has seen at least one at some point in their lives. But a total solar eclipse is rare for any given location, with an incidence of just one each 360 years, on average. Our mid-Hudson region last saw one on January 24, 1925. And we’ll next get a total solar eclipse on May 1, 2079.
But when a solar totality happens, it is so stunning, so mind-blowing, that many people weep from the emotional impact. All sorts of things happen during a solar totality. Pink flames called prominences leap from the edge of the Sun. The Sun’s atmosphere, called the corona, throws filamentary patterns far into the sky that radiate from the Sun’s location. Animals go crazy. An observer told me, after the 1980 totality in India, that it felt like “the home of my soul.” It is the greatest visual experience a human being can ever have.
And yet its extraordinary nature is so routinely overlooked that relatively few will drive 100 miles to place themselves within the path of totality, and instead will remain in their own backyard even though the eclipse is merely 97% total from their home. They figure, “well if I’m going to get 97% of the full darkness that’s close enough, right?” — because too many imagine that the big draw is seeing “darkness at noon.” They don’t realize that only totality offers unique life-altering phenomena.
So on April 8, 2024 when the path of totality moves northeast from Texas to sweep over Cleveland, Buffalo, Rochester, Burlington VT, and then across northern New Hampshire and northern Maine, you will first have to decide whether to pilgrimage to one of the places within that 100-mile wide magical ribbon of totality.
But those are questions to be answered two years from now. Coming up later this month you’ll have the much easier decision of whether to stay up and simply look into the sky. If it’s a clear night the full Moon will start changing its appearance at 10:38 p.m., a fairly convenient starting time. No need to set the alarm for the wee hours.
We’ll explore the details, and what to look for during this first total lunar eclipse in years, next week.