It really feels like we are settling in to 2024 at this point, and hopefully the year is going well for you so far! We are finally heading into the spring months, and hopefully the constant weather warnings will abate long enough for us to get out and do some relaxing stargazing.
In fact, the Vernal Equinox takes place on the 20th of March this year, and marks the start of astronomical spring in the northern hemisphere. This is one of the two days of the year where the length of the day and night are equal, and the sun lies directly over the equator. Interestingly these are also the only days of the year where the line between the lit and unlit portions of Earth (the terminator. Yes, really) is perpendicular to the equator.
The vernal equinox marks the beginning of the new year in some calendars, including the Hindu and Assyrian calendars. In Celtic pagan cultures, Ostara, the march equinox, marks the midpoint between Imbolc (1st Feb) and Beltane (1st May), This is when the balance between dark and light is reinstated with light increasing from here. It represents new beginnings and the re-emergence of life from the grips of the winter cold. In Chinese culture, the Spring equinox marks the beginning of the fourth solar term of the 24 that divide the year into equal parts (the name ‘chinese equinox’ is also often used to mean this fourth solar term, in general). In Italy the tradition on this date is to plant seeds, whereas in Japan it is tradition to visit the graves of your ancestors.
Early in this month we have the new moon, when the best time for stargazing of the month rolls around. The skies are as dark as they get each month, so take a look out for the spring constellations coming into view, and even potentially a few deep sky objects.
Later on in the month, then as is the natural cycle of things, we get the Full moon. This may have more significance to you, especially if you work in healthcare, or even very closely with people, as there is a pervasive belief that people get wilder on the full moon! I’m not here to throw stones, though, so I’ll settle for telling you about the full moon of March, which will take place on the 25th of the month. It is known this month as the worm moon (my favourite moon of the year. I love me some worms) due to the fact that this is the time of year that earthworms start to emerge from their slumbers underground. Other names include: the crow moon (as the crows start to become more active after winter), the crust moon (after the crust of snow left as it refreezes) and the sap moon (as the sap of maple trees starts to flow – and can be used to make maple syrup!).
Just before the full moon, however, is a celestial event that means that Mercury is at its easiest to see in the sky; Mercury’s greatest Eastern elongation. This is when Mercury is at its furthest from the sun, and so makes it much easier to see than at other times, when it is too close, and therefore outshone, by the sun. In fact, it is only for a few weeks either side of the greatest elongation that Mercury is visible in the sky at all – lost in the halo of the sun most of the time.
One of the constellations that are visible in the early spring sky is Auriga. Auriga itself represents the charioteer – a person who (as you might have guessed) drove a chariot. This constellation is one of the 48 original constellations officially listed by Ptolemy in the 2nd Century AD.
Auriga could represent a number of actual mythological figures. One of these is Phaethon, sun of the sun god Helios. Phaethon went out to ride in his father’s chariot for the first time, after having tricked his father into letting him use it. Phaethon then crashed his father’s chariot and burned the earth, and then was placed in the night sky as Auriga. Phaethon is also the name given to the only known asteroid to be the cause of a meteor shower.
Auriga is not alone in the sky, though, as his companion accompanies him – Capella, the brightest star in the constellation of Auriga. This star represents the charioteer’s goat, and the name Capella itself means little goat. The star is actually reasonably close to the Earth, at only 42.9 light years away from the Sun. Although this star looks just like every other star in the sky with the naked eye, it is in fact a multiple star system – a quadruple star system to be exact, with two pairs of binary stars. Capella Aa and Ab (the two in the primary pair) are two yellow giant stars, very like our own sun with each around twice the size of our star.
Capella belongs to Auriga, but it also makes up a part of the winter circle, an asterism that is nice to look out for in the winter, (and early spring) sky. It’s made up of stars from six different winter constellations, including Gemini, Canis major and minor, Orion and taurus in addition to Auriga.
Auriga also contains within its borders the galactic anticenter – this is the point in exactly the opposite direction to the galactic centre. If you travelled in the direction of the galactic anticenter you would get to the edge of the galaxy in the shortest time (but not a short time).
Cancer the Crab. Image Credit: Stellarium/Anna Taylor
Cancer is another constellation that you might see in the march night sky. You’ll probably recognize it as one of the signs of the zodiac. You’ll be able to see Cancer in the west of the sky, slowly moving to the north throughout the month. This constellation has a few reasonably faint stars, but one of these in particular is really interesting. 55 Cancri, also known as Rho1 (ρ1) Cancri, a binary star system, is one of ten stars or star systems in Cancer known to have planets, but this one in particular is a doozy. It has five extrasolar planets orbiting its main star 55 Cancri A, flamboyantly named 55 Cancri b, c, d, e and f. the closest of these planets to the star is 55 Cancri e, a super earth. This planet is in the habitable zone of the star and is expected to have a similar temperature range to Earth. The other four planets orbiting 55 Cancri A are gas giants and are thought, like Jupiter and Saturn, to be composed mostly of Hydrogen and Helium.
M44/NGC , also known as the Beehive Cluster. Image Credit: Wikipedia
One of the deep sky objects that Cancer is well known for is the Beehive Cluster (M44/NGC 2632). This is an open cluster of stars, that have been born and moved from their birth nebula (as such) but not moved very far apart from each other yet. Interestingly, this cluster was one of the first things Galileo looked at with his telescope. It is one of the closest open clusters to our solar system (600 light years away), and, at about 1000 stars, contains more stars than other open clusters in proximity.
So there’s plenty of things to look out for in the Night sky this March, and if you’re feeling festive, there’s even a celestial shamrock for St Patrick’s Day, chosen specially by NASA and one of their surveys!
Have a nice March, and enjoy your stargazing as it (supposedly) heats up a little!
A Celestial Shamrock
This image from NASA’s Wide-field Infrared Survey Explorer, or WISE, features a region of star birth wrapped in a blanket of dust, colored green in this infrared view. Credit: NASA/JPL-Caltech/UCLA
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