#Moon phases august 2021 full

The 5 degree tilt of the Moon’s orbit also causes it to appear to nod, as though it were saying “yes.” The tilt sometimes brings the Moon above Earth’s northern hemisphere, and sometimes below Earth’s southern hemisphere, allowing us to see slightly more of the northern or southern hemispheres of the Moon.

We call this motion “libration in longitude.” When the Moon is farthest from Earth and orbiting at its slowest, its rotation gets a little ahead, and we see a bit more of its western side. When the Moon is at its closest to Earth and moving most quickly along its orbital path, the Moon itself doesn’t rotate quite fast enough to keep entirely the same side facing us, and we get to see a little more of the eastern side of the Moon. The Moon’s rate of rotation around its own axis, though, always stays the same. 30, 2023 to be exact.Because the Moon's orbit is not perfectly circular, its distance from Earth and its speed in orbit both change slightly throughout the month.

#Moon phases august 2021 full

If you go by the 'Pruett two full moons in a month rule,' the next blue moon will also come in the month of August - Aug. So, when are the next Blue Moons after this Sunday? Consider this column an updated version for 2021. And as it turns out, the last time we had a blue moon based on the 'four full moons in a season' rule was in May 2019. Here at, we have posted many stories regarding the differences between the two blue moon definitions over the years. But nothing out of the ordinary has occurred in recent days or weeks, so this weekend's moon should look pretty much the way we are accustomed to seeing it.

In the past, there have been very unusual atmospheric circumstances that have caused the moon (and the sun) to appear bluish, caused by anthropogenic aerosols injected into the atmosphere such as volcanic ash and dust (after the eruption of the Krakatoa volcano in August 1883) or airborne soot from forest fires (such as from western Canada in September 1950). Of course, to everyone who sees it, it will still look full, even though it will be ever-so-slightly out of perfect roundness.Īnd don't expect to see the moon shine with a bluish tint. That means that for North America, the moon phase will be just past full - actually a waning gibbous moon - when it comes over the horizon at nightfall that Sunday evening. The third full moon - the Blue Moon according to the original rule set down by the Maine Farmers' Almanac - comes on Sunday, with the moon officially turning full at 8:02 a.m. So, going by the old 'Maine Almanac rule,' for summer 2021, we have four full moons: June 24, July 23, Aug. You should not confuse it with The Farmers' Almanac which has been publishing continuously since 1818, but coincidentally also happens to be based in Lewiston, Maine.

Meanwhile, the 'original' Maine Farmers' Almanac rule had been all but forgotten.Īs was noted earlier, that publication has long since gone out of business. Pruett's misinterpretation gained traction with a new audience of baby boomers, and today his 'two full moons in a month rule' is recognized worldwide. Pruett's 1946 explanation was, of course, the wrong interpretation and it might have been completely forgotten were it not for journalist Deborah Byrd, who used it on her popular National Public Radio program, StarDate on Jan. This second in a month, so I interpret it, was called Blue Moon.' This gives 11 months with one full moon each and one with two. 'Seven times in 19 years there were - and still are - 13 full moons in a year. Pruett unfortunately came to this conclusion: This time, on page 3 of the March 1946 issue, James Hugh Pruett wrote an article, ' Once in a Blue Moon,' in which he made a reference to the term 'Blue Moon' and the S&T article from July 1943. Once again, we must turn to the pages of Sky & Telescope.