It’s the first full Moon of meteorological spring, and the last full Moon of astronomical winter.
With the green comet making its first appearance since the time of the Neanderthals, sightings of aurora and the Venus-Jupiter conjunction, stargazers in the UK have had a busy start to the year.
Astronomical spring is rapidly approaching, and on the 20 March, the Sun will cross the celestial equator from south to north, when night and day will be of (almost) equal length. Of course, we know this as the equinox, which signals the start of astronomical spring in the northern hemisphere, and the start of daylight-saving time (DST).
So when can you see the Worm Moon? What constellation is the Moon in? And, what does it have to do with worms?
If you’re looking to take advantage of clear nights this year, why not check out our full Moon UK calendar and astronomy for beginners guide?
When can I see the Worm Moon 2023?
The full Worm Moon is the third full Moon of the new year, and the first full Moon of meteorological spring. It will be visible Tuesday 7 March 2023 and can be seen in the late afternoon/early evening, rising high overhead later in the evening, in the UK and the northern hemisphere.
The Moon will rise in the east-northeast at 5:48pm on Tuesday 7 March 2023, as the Sun sets. The Moon will set at 7:10am the next morning in the west, on 8 March 2023 as seen from London (times vary with location).
If weather spoils the occasion, or you are unable to see the full Worm Moon at its peak, it will also appear full the night before, and the night after.
What constellation will the Worm Moon be in 2023?
On 3 March, the Moon passed 1.7 degrees south of Pollux, the brightest star in the constellation Gemini. On 6 March, the Moon will be 4.5 degrees north of Regulus, the brightest star in the constellation Leo.
At the time of full, the Moon will be just in the constellation Virgo near to the red giant variable star, Nu Virginis, having moved there from its previous home of Leo, the night before. The Moon spends around two to three days in each of the zodiac constellations, as it progresses through its lunar cycle.
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Then later in the month, the now-crescent Moon will be around 3.6 degrees south of Saturn in the morning sky of 19 March, before passing 2.4 degrees south of Neptune on 21 March. On 22 March, in twilight, the Moon will pass south of Mercury and Jupiter, although this may be a little tricky to see from built up areas, as it will be close to the horizon at this time.
What is the best time to see the Worm Moon?
Peak illumination occurs when the Moon reaches syzygy (when the Sun, Earth, and Moon line up perfectly), which here in the UK is at 12:40 GMT. However, we won’t physically be able to see the Moon at the precise moment of 100 per cent illumination, as it’s below the horizon at this time.
The easiest time to see the Worm Moon at its brightest will be in the evening of the 7 March, after the Sun has set at 5:50pm. At this time, the Moon will be low on the horizon and lingering in the twilight sky. If conditions are clear, we should be offered a decent view throughout the night, until it sets the following morning with the appearance of the rising Sun.
Why is it called the Worm Moon?
This month’s full Moon is named after the earthworms that traditionally begin to emerge from the soil at this time, becoming more active as the winter frost thaws and spring approaches. The Worm Moon marks the final full moon of astronomical winter and the beginning of the transition to spring in the Northern Hemisphere.
Another popular name for the March full Moon is the Crow Moon, as the birds become more active, keen to feed on the juicy worms after the long winter months. The dark feathers stand out against the still-bare trees, so although there are other birds active, it’s the corvids which are particularly apparent.
The names for the monthly full Moons hark back to the 1930s, when the Maine Farmer’s Almanac began publishing Native American names for the full Moons in each month of the year. Since then, these names have widely been adopted around the world.
Is the Worm Moon in 2023 a supermoon?
Nope. The Worm Moon in 2023 is not a supermoon.
A supermoon is an unofficial classification for when the Moon is situated 360,000km (or less) away from Earth in its orbital path, and we’ll often have two or three full supermoons in a row.
At peak illumination, the Worm Moon in 2023 is around 403,658 km away from the Earth, so does not fall into the supermoon category.
The first supermoon of 2023 will be 1 August, with a rare blue supermoon hot on its heels at the end of the month, 31 August. The July (361,934km) and September (361,552km) Moons come pretty close, so although will appear bigger and brighter to us – are slightly over the 360,000km distance. That being said, when taking into account the preceding or succeeding apogee and perigee, the July and September Moons do classify as a supermoon.
In 2022, the Strawberry Moon (June), the Buck Moon (July) and the Sturgeon Moon (August) were all supermoons.
What else can I see?
Following the closest approach of Jupiter and Venus at the start of the month, the two planets are now rapidly separating, but on 22 March, we’ll be treated to a view of Jupiter passing a razor-thin crescent Moon, before passing close to Mercury on 27 March.
Looking north, Ursa Major is now upside down, and high in the sky for observers north of the equator. Looking above the Moon, eagle eyes may also be able to make out the constellation Leo through the glare of the reflected moonlight, as it leads the way for the Moon rising throughout the night.
Full Moons and the lunar cycle
A full Moon is one part of the lunar cycle, the continuous series of changes that the Moon undergoes as it orbits the Earth and its relative position in the sky with respect to the Sun. The phases of the lunar cycle include New Moon, Waxing Crescent, First Quarter, Waxing Gibbous, Full Moon, Waning Gibbous, Third Quarter, and Waning Crescent.
The lunar cycle takes around 29.53 days to complete, which is why the term ‘lunar month’ is often used to describe the time period between successive full moons. This is also sometimes referred to as one synodic month.
A full Moon occurs when the Moon is fully illuminated by the Sun, which happens when the Earth is positioned directly between the Sun and the Moon.
In other words, the Moon is located precisely 180 degrees opposite the Sun in ecliptic longitude. We usually have 12 full Moons in one calendar year, although some years we can have 13. The extra full Moon is known as a ‘Blue Moon’ – and we have one this year, 31 August.
Read more:
- With two-week nights, Moon colonisers will have a seriously weird daily cycle
- What would it mean for biodiversity on Earth, if the Moon was completely black?
- The Royal Astronomical Society is searching for the UK’s “Moon Trees”