Spring arrives this month, with the Vernal (spring) equinox on 20 March, when day and night are each 12 hours long. On that day, the Sun rises at about 6:20 am due east and sets at about 6:20 pm due west. From then on, the nights get shorter and the days get longer. British Summer Time (Daylight Saving Time) starts on 27 March, so it gets dark a lot later in the evening. Don’t be put off with it getting darker later and the nights becoming shorter. There is still much to see, with the bright winter constellations still visible and the constellation of Leo (The Lion) coming in to view. Now is also a great time of year to spot Zodiacal Light, the night sky’s most elusive phenomenon.
This month, the sun sets around 6:30 pm and the stars and the constellations start to become visible from about 8:30 pm onwards. If you look south, you will still see the winter constellations of Orion, Taurus, Auriga and Gemini that I described in on my “Exploring Our Night Sky: February 2022” blog at the start of last month. Bear in mind that they will have moved a little bit to the west. Also, you will now be able to see some of the spring constellations coming into view, with the most significant of these being Leo (The Lion), which will be high up in the south-east sky.
Looking North, the thing to bear in mind is that the constellations you see do not change from month to month, it is only their orientation that changes. You can find the seven stars of the Plough up in the north-east and you can use its two right-hand stars to find the Pole Star, Polaris, which is always in the same position in the sky. Just follow the line between them for about five times its length and you’ll arrive at it.
Once you’ve found Polaris, you can use it to get your bearings on any night but bear in mind that all the northern constellations rotate around it in an anticlockwise direction and therefore change their position. It is also worth noting that Polaris is not that bright, with it being about the same brightness as the stars of the Plough. Its significance comes from it being directly above our North Pole. It’s just by chance that this millennium it happens to be very close to the pole of the northern sky, but there is a slow movement of the sky over the centuries that shifts the position of the stars, and 1000 years ago it wasn’t as close as it is now.
The constellation of Auriga (the Charioteer) was pretty much overhead last month and is now starting to sink down towards the western horizon but it’s still high up. It’s in the shape of a pentagon, with Capella, one of the brightest stars in the sky, at its northern tip. Next to Capella is a triangle of three stars which, though much fainter, makes the whole constellation very recognisable. Below Auriga is the constellation of Perseus who, in Greek mythology, beheaded the Gorgon Medusa for Polydectes and saved Andromeda from the sea monster Cetus. Also, below Perseus, you may be able to pick out the W-shape of the constellation of Cassiopeia, so named after the vain queen Cassiopeia in Greek mythology, who boasted about her unrivalled beauty.
This month’s full Moon is on 18 March, becoming 100% full at 7:17 am. This means that it will appear full on the nights of 16-17 March, 17-18 March, and 18-19 March. It will rise in the east at about 4:00 pm on the 16 March, at about 5:30 pm on the 17 March and at about 7:00 pm on 18 March. It is referred to as the Worm Moon because of the earthworms that come out at the end of winter. It is also known as the Crow Moon, Crust Moon, Sap Moon, Sugar Moon, and Chaste Moon. The Old English/Anglo-Saxon name is Lenten Moon.
On the night of 15-16 March, then moon will spend the night traversing the sky close to Regulus, the brightest star in the zodiacal constellation of Taurus, while on the night of 19-20 March, it be close to Spica, the brightest star in the zodiacal constellation Virgo.
The last quarter Moon is on 25 March and on 28 March and you will see it rising in the south-east at about 7:00 am with Venus, Saturn, and Mars above it.
This month there are no bright planets in the night sky, with the exception of Uranus which, at a magnitude of +5.8 will be very difficult to see.
If you do want to see some planets, you will either need to stay awake for most of the night or get up early and watch Venus rising in the south-east at around 4:30 am. It is shining very bright this month, at a magnitude of -4.4 and reaches its maximum separation from the Sun on 20 March. If you look at it through a telescope, you should be able to see it as a thick crescent which broadens as the month progresses. It reaches dichotomy on 21 March when it is exactly half illuminated.
Mars spends the month below and to the right of Venus, rising at around 5:00 am and will be over 100 times fainter at a magnitude of +1.1. Saturn rises about half an hour later and will be in-between Venus and Mars.
Jupiter, Neptune and Mercury are lost in the Sun’s glare this month.
We are now in a quiet period for meteor showers, until the Lyrid meteor becomes active on 16 April. It will peak on the night of 21-22 April and the best time to look for them will be between sunset and when the moon rises at about 3:30 am.
The Zodiac is an 8° wide band that straddles the ecliptic, the invisible path that the Sun traces as it moves around the sky and is the region of the sky where we can find the Sun, Moon and planets (except for Pluto). It is only 8° wide because most of the planets have orbits that are only slightly inclined to that of the Earth. The exception is Pluto, whose orbital inclination of 17° takes it out of the zodiac during part of its orbit.
At this time of year, the Zodiac rises steeply from the horizon at dusk, meaning now is great for looking out for and observing one of the night sky’s most elusive phenomena: Zodiacal Light. It is fainter than the Milky Way, so the darker your sky, the better your chances of seeing it. Go to a location with little or no night pollution, on a night when the moon is out of the sky and look for it in the west in the hour or two after sunset. If you are lucky, you may spot a faint pyramid of light rising from the horizon.
This ghostly glow is caused by light from the sun, which will be well below the horizon at that time, reflecting off a fog of tiny interplanetary dust particles that fill our inner Solar System. It’s so difficult to see and many astronomers have never witnessed it, however, I was lucky enough to spot and photograph it at Sailean nan Cuileag around this time last year and I’ve used the resulting image as the header photo for this blog. The conditions for spotting it are good for the next 2-3 months, so do keep an eye out for it.