2019 Super, Micro, Black & Blue Moons

Starter Note: When an event happens on a certain date, it’s important to check the actual time of the event because remember; a calendar day is a period of daylight sandwiched between two periods of darkness. Thus, an event (especially with the Moon) might not take place that night at all but instead in the morning before sunrise and you might be disappointed that you have already missed it.


Simply stated, a supermoon is a full or new moon (though most only acknowledge full moons) that occurs within 90% of perigee (Moon’s closest point relative Earth in its orbit).

Are they really bigger?:

It all comes down to apparent size or how it looks on the sky. As far as the actual Moon, it’s still its usual 2,159 mi. (3,474.5 km) diameter self. So how does the Moon appear to be different sizes at different times? Orbital mechanics; We tend to draw orbits in circles and they’re usually not too far off but the truth is, they’re slightly elliptical (oval) which means sometimes the Moon is closer to Earth than it is at other times. When the Moon is at its closest point to Earth, it’s called perigee. When the Moon is at its furthest point from Earth it’s called apogee. The “gee” in these words is for geo or Earth while “peri” is near and ‘apo’ is far (all Greek). The words apogee and perigee are actually French with Greek origins.


As you can see from the distances below, the Moon from perigee to apogee is only about a 10% change so like I said above, the orbit isn’t a perfect circle but it’s really not too far off. That 10% distance change makes full supermoons about 14% larger and 30% brighter than their full micromoon counterparts. That sure does sound like a lot (and it is) but it’s really difficult to notice the difference.  Even those of us who view the moon all month long for its different phases and features have a hard time distinguishing the difference in apparent (angular) size and associated brightness.

Moon’s average distance from Earth is 238,900 mi. (384,472 km.)

Moon’s average perigee (close): 225,804 mi (363,396 km).

Moon’s average apogee (far): 251,968 mi. (405,504 km).

What effect will it have?:

Not much really.  You may notice slightly larger than normal tides but even then were not talking about much.  If you live in a low lying costal area you may notice a difference of a few feet, maximum.

Where did the name “supermoon” come from?:

Historically (and still today) astronomers call a full or new moon that lands on the night of perigee a perigee or proxigean full or new moon, though due to the title supermoon catching on many are running with that name as it’s a pretty cool name and the parameters that it works within allow for about 4-6 per year. The term supermoon comes not from science but from astrology; more specifically, astrologer Richard Nolle who coined the phrase and set guidelines that state any new or full moon within 90% of perigee is a supermoon. So there you go, it’s not a big deal but either way it’s encouraging people who otherwise wouldn’t be looking up to do so and that is certainly a good thing in my opinion. If you have questions, as always please ask.

2019 Supermoon(s):

Monday, January 21, 2019 (full moon, total lunar eclipse & largest of 2019)

Tuesday, February 19, 2019 (full moon)

Thursday, March 21, 2019 (full moon)

Thursday, August 01, 2019 (new moon)

Friday, August 30, 2019 (new moon & closest new moon of the year)

Saturday, September 28, 2019 (new moon)




Just read what a supermoon is in the above writing and reverse everything. Ok, ok I’ll go into a little more detail but that truly covers it. A micromoon is when a full or new moon is within 90% of apogee (Moon’s furthest point relative Earth in its orbit).

Sticking to the crude but pretty accurate model of simply reversing the supermoon criteria, a micromoon may look upwards of 14% smaller and 30% dimmer than their supermoon counterparts as they are roughly 10% further away.

Moon’s average distance from Earth is 238,900 mi. (384,472 km.)

Moon’s average perigee (close): 225,804 mi (363,396 km).

Moon’s average apogee (far): 251,968 mi. (405,504 km).

2019 Micromoon(s):

Monday, February 4, 2019 (new moon)

Saturday, September 14, 2019 (full moon)



Black Moon:

The term Black Moon, like Super Moon, isn’t associated with astronomy at all but instead it comes from witchcraft and again, like the Super Moon, can be used on a few different occasions; five (5) to be precise.

Type 1: Calendar black moon: When there are two new moons in a calendar month, the 2nd new moon is a black moon.

Type 2: Seasonal black moon: When there are 4 new moons in a season (defined by equinoxes & solstices, not calendar quarters) the 3rd new moon is a black moon.

Type 3: When there is no new moon at all in a calendar month.

Type 4: When there is no full moon at all in a calendar month.

Type 5: During a solar eclipse, where the Moon actually looks black on the sky.

2019 Black Moon(s):

Wednesday, July 31, 2019 (2nd new moon in July)

Friday, August 30, 2019 (2nd new moon of August)



Blue Moon:

Similar to the two pervious Moon events we detailed above; the Blue Moon can be used in a few different scenarios. Let’s have a look at all three (3) of them.

Type 1: Two (2) Full Moons that occur in a single calendar month are called “CALENDAR” Blue Moons. They tend to occur on average every 2.7 years-ish and this is today’s “modern” definition of the event. The last one was last year, (July 31, 2015) and the next few of this type will take place on:

October 31, 2020

Type 2: These oddballs are called “SEASONAL” Blue Moons but I like to call em your Grandfather’s Blue Moons as they are the old school, original definition of the event. The standard was, that a Blue Moon was any season that had 4 full moons….the 3rd of which was considered a Blue Moon. Seasons by calendar are defined as the time periods between SOLSTICES and EQUINOXES or vice versa. The last one was on August 21, 2013 (3rd of 4 full moons of summer) and the next Blue moons of this sort will fall on:

May 18, 2019

August 22, 2021

Type 3: The final type of Blue Moon is an actual BLUE MOON…..but you’re going to need some tools; preferably an active volcano, massive amounts of ash and an atmosphere to deploy it into. For years volcanic eruptions have been associated with blue colored Moons; why? Most volcanic ash is about 1micron wide which just happens to be the length of a wavelength of red light. Thus, the red light is scattered and the blue shows through. Massive fires also have the ability to do this as well. Ever notice something looking bluish (Forest fires, grill smoke etc.) as you view it through smoke? There you go…..




Final thoughts:

Keep in mind that none of this is actually relevant to our day to day lives, actual astronomy or anything else. It’s just orbital mechanics wrestling with our human constructed calendar system and on occasion it delivers to us an oddity that we can have some fun with. As far as popular culture is concerned; like the “supermoons, micromoons, blackmoons etc.” just embrace it and enjoy seeing something unusual even though we pretty much created it. Like anything else similar in nature to this; if it gets people to look up when they otherwise wouldn’t, I’m all for it.

Quality Moon Calendars/Calculators: