Super Worm Moon is 2019's third, final supermoon on 21 March: When, where to watch

Prepare yourselves, skygazers!The final supermoon of 2019 is soon arriving and shares a date with the spring equinox, which marks the technical beginning of spring. This is the first time in 19 years that both these celestial events have shared a date.The 21 March spectacle is the third back-to-back supermoon this year, with the first on 21 January and the biggest and brightest of the three taking place on 19 February.[caption id="attachment_6293501" align="alignnone" width="1280"]

The supermoon is not as rare as you might think. Image: Flickr[/caption]

What's a supermoon?

Supermoons are a rarer event than this year's record might suggest but they're not "rare" per se.As the moon makes its monthly trip around the Earth, it takes an elliptical, and not a circular, path. All the objects in the solar system orbit this way, including the Earth around the Sun.Sometimes, a full moon reaches its closest distance from the Earth in its elliptical, monthly orbit around the planet. When it does, we see a supermoon — slightly larger and brighter in the night sky than other full moons, but subtly so.[caption id="attachment_6293531" align="alignnone" width="1280"]

Phases of the moon orbiting the Earth. Image: NASA[/caption]

The spring equinox

A full moon has not landed this close to the first day of spring since 2000, and these celestial events won’t clash like they will on 21 March until 2030, according to astronomy website EarthSky.org. The March equinox, also called the Spring Equinox or vernal equinox, marks one of the four milestones in Earth’s seasonal cycles. The four equinoxes are marked every year because the planet is tilted on its axis — so, for the majority of the year, one of the hemispheres is significantly closer to the sun and experiencing longer days than the other. But on the day of an equinox, this tilt vanishes. Both halves of the planet experience equal amounts of day and night.For the Northern Hemisphere, the equinox in March marks the beginning of spring. In the Southern Hemisphere, it's the official start of autumn.[caption id="attachment_6114181" align="alignnone" width="1280"]

How the supermoon, full moon and micromoon differ in size.[/caption]

The super worm moon

In the north, the full moon in March is referred to as the "worm moon" since it clashes with the time in the year when earthworms start to come up from thawing winter soils. The equinox supermoon on 21 March is also going by the odd name "super worm moon" for this reason.

When & where to watch the lunacy