These are more common and less super than you might think. Writers love sensational sounding names and headlines because readers like them. The click bait title above from a question I was asked on Quora is a great example. Even a common event is just more interesting when described with words like “blood” and “super”.
A Blood Moon is a slang expression for a Total Lunar Eclipse.
A Super Moon is a slang expression for a Full Moon at Perigee Syzygy. Perigee means that the Moon is at the closest point in its elliptical orbit. A perigee Moon appears only about 14% larger than when the Moon is furthest (apogee) - not very super! The illusion of the Moon appearing larger near the horizon than overhead is more striking than this.
Syzygy means that the Sun, Earth, and Moon are all in a straight line when viewed perpendicular to the earth’s orbital plane. All full moons occur at a syzygy as well as solar and lunar eclipses.
Perigee occurs at an exact moment in time; I will use a rule of thumb that any full Moon within 10% of perigee is a Super Moon. With astronomical precision, we are looking for within 90% of Perigee Total Lunar Eclipses. Something like this one from last January:
Eclipse expert Fred Espenak has done the hard work. Using data from two of his tables at: NASA’s Lunar Eclipse page and AstroPixels Full Moon at Perigee (Super Moon): 2001 to 2100 page, I've extracted the dates for the 21st century. The next Super Moon Total Lunar Eclipse (90% of Perigee Total Lunar Eclipse) will be: 2021 May 26.
Between 2001 and 2100 there will be 85 Total Lunar Eclipses and 28 Super Moon Total Lunar Eclipses. Almost 1/3 of Total Lunar Eclipses in the 21st century will occur during a Super Moon. They occur on average about 3.5 years apart. Here is the list for the rest of the 21st century:
Content created: 2019-03-05
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