Look up: eclipses, supermoons & meteor showers to see in Irish skies in 2025
Opinion: Kevin Nolan, Recently published on RTE Brainstorm
Celestial events can engender a sense of wonder about the grand scheme of nature and our place in it. While all celestial objects apparently move across the sky daily as the Earth rotates, it is more challenging to see their real motion as they travel through space.
But there are events such as eclipses and occultations of the planets by the Moon that reveal the true motion and harmony of the heavens. Numerous such events will occur in 2025 which require no optical aid whatsoever - all you need to know is when to look up and where in the sky to direct your eyes!
Eclipses
There are two kinds of eclipses. A solar eclipse occurs when the Moon moves between the Earth and the Sun, blocking the Sun's light because of the cosmic coincidence that the Moon and Sun appear the same size in the sky.
Conversely, if the Moon, Earth and Sun line up with the Earth in the middle, then the Earth's shadow is cast onto the Moon's surface, causing it to dim in the night sky for a few hours in what is called a lunar eclipse. This year no less than three eclipses are partially visible from Ireland - two lunar and one solar eclipse.
Total Lunar Eclipse: March 14th
The first lunar eclipses occurs in the early hours of March 14th. The eclipse begins at 4am, with totality at 6.30am. We will only get to see half of this eclipse as moonset is at 6.45am, but it will be magnificent to see the Earth's shadow slowly travel across the Moon. If you are an early riser, this is truly worth a look.
Partial Solar Eclipse - March 29th
On the other side of its orbit two weeks later, the Moon will move between Earth and the Sun, causing a solar eclipse. This is only a partial eclipse meaning that about 40% of the Sun's disk is blocked as viewed from Ireland. The eclipse begins at 10am and ends two hours later. While the sky may dim, do not look at the Sun directly. Instead, the eclipse can only be viewed using authorised solar eclipse viewing glasses, widely available.
Total Lunar Eclipse - September 29th
The third of our eclipses for the year is another total lunar eclipse on September 29th. This time we get to see the second half of the eclipse in the evening eastern sky, with the Moon rising at 7pm and the eclipse continuing until 9pm. Once again however, it is a sight to behold to see Earth's shadow move across the Moon's surface as it moves on its orbit around the Earth.
Planets and occultations
The night sky up to April 2025 is exquisite for viewing Venus, Mars, Jupiter and Saturn. A beautiful spectacle will span the sky looking south on the evenings of January 21st and 22nd when six of the planets will align in a huge arc from east to west: Mars, Jupiter, Uranus, Venus, Neptune and Saturn.
Jupiter in particular is very bright high in the southern sky - above the constellation of Orion - and is worth a look through binoculars where you'll see its four "Galilean Moons" - Io, Europa, Callisto and Ganymede - glistening like tiny diamonds next to the planet itself. On January 18th, look west after sunset for the beautiful sight of Venus and Saturn very close to each other; with Venus the brightest object in the night sky after the Moon by some margin.
Some stunning occultations will also occur in 2025 where the Moon moves in front of other more remote objects as it orbits the Earth, again revealing its real celestial motion. On January 4th, look southeast at 5.18pm and you'll see Saturn at upper left of the Moon, whereupon the Moon then occults Saturn until it reappears lower right of the Moon at 6.26pm. A small telescope will reveal Saturn's rings too, providing a magnificent view of the real-time motion of the Moon in relation to Saturn.
At 7pm on February 9th, the Moon moves very close to Mars. While it does not occult Mars on this occasion, their relative position to each other will nevertheless noticeably change over the hours as the Moon moves by in its orbit.
Finally, the Moon occults the beautiful Pleiades star cluster in the constellation of Taurus on April 1st. Look southeast around 10pm with the unaided eye and you will see the Moon nested among the famous "seven sisters" star cluster, and through binoculars will be breath-taking.
Supermoons
A Supermoon is also a beautiful event to witness. This is where a full moon occurs at the same time as the Moon is at its closest point along its orbit to us, rendering it up to 13% larger in the sky and casting up to 30% more light than usual. This year we're lucky to have Supermoons on October 7th, November 5th and December 4th. Put those dates in your diary!
Meteor Showers
Meteor showers occur when the Earth passes through rings of dust circling the Sun left behind by passing comets. Some 110 such showers occur every year, but only some of them result in spectacular viewing of shooting stars: dust particles burning up when they enter in the upper atmosphere at up to 250,000km per hour!
Depending on the orientation of the dust lane as Earth passes through it, we see the resultant meteors or shooting stars emanate from a particular part of the sky. Meteor showers are named according to what constellation they seem to radiate from.
To view a meteor shower, where you may see over 100 shooting stars per hour for a good maximum night, all you have to do is wrap up well and spend an hour or so outdoor on the evening of the meteor shower maximum - and look up! You do not even have to look in the direction of the constellation they emanate from as shooting stars shoot across large portions of the sky.
Three of the best meteor showers to take note of are the Quadrantids which emanate from the Plough and peak on the first couple of nights of January; the Perseids, which emanate from Perseus and peak on August 12th; and the Geminids, that radiate from Gemini and peak on December 14th.
For more information, check out such sky-related events as Irish Astronomy Week (March 1st-8th), Skellig Coast Dark Sky Festival (March 28th-30th) and National Space Week (October 4th-10th).
Kevin Nolan is a Lecturer in Physics at TU Dublin and a PhD candidate in Space Science.
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