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:

When is the next one?

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.

How common are they?

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:

• 2021 May 26
• 2022 May 16
• 2032 Oct 18
• 2033 Oct 08
• 2036 Feb 11
• 2037 Jan 31
• 2040 May 26
• 2050 Oct 30
• 2051 Oct 19
• 2054 Feb 22
• 2055 Feb 11
• 2058 Jun 06
• 2068 Nov 09
• 2069 Oct 30
• 2072 Mar 04
• 2073 Feb 22
• 2076 Jun 17
• 2087 Nov 10
• 2090 Mar 15
• 2091 Mar 05
• 2094 Jun 28