The key to astronomy is knowing how to get around. When travelling to another country we familiarize ourselves with its cities using maps and the same can be said for the sky – we need to familiarize ourselves with it before we can explore it properly. Whether you want to become an amateur astronomer or simply enjoy the vista as you lie back on your deckchair and impress your friends with your deep knowledge of the heavens, understanding the constellations will literally open new horizons.Being able to recognize patterns in the night sky is indispensable – not only is it an enjoyable exercise in itself, it also helps you make heads and tails of the countless dots and points of light, and use them to find other, fainter, deep sky objects. As you become acquainted with the stars, these randomly scattered points of light will take shape into familiar patterns recognizable at a glance.
As promised in the first entry of this guide, throughout the year we’ll explore 12 constellations of the zodiac as well as a few other constellations, discovering the wealth of objects found within their boundaries. Our journey begins with one of these few others: Orion, probably the most familiar pattern in the sky, and perhaps also the loveliest for Maltese and Northern Hemisphere observers.
According to Greek mythology, Orion was a powerful hunter, whose death was either brought by the bite of a Scorpion, or by a fatal blow from Artemis. In the heavens, Orion is standing next to the river Eridanus with his two hunting dogs Canis Major and Canis Minor, fighting Taurus the bull. Another prey of his, Lepus, the hare, can be found just beneath Rigel; it is a faint constellation made of relatively faint stars, but the zigzag pattern can be made out with only a slight effort.
Orion is easily distinguishable in the night sky and stands out with its unique pattern and the wonderful and incredibly symmetrical asterism of Orion’s belt: three equidistant stars forming a diagonal right in the middle of the constellation. A good place to observe Orion this month is Dingli Cliffs – Orion rises on the dark sea below to the south. Look for it somewhere above Filfla; you should easily spot the unmistakable pattern of stars making up Orion.
Now is the time to put your binoculars to use. The Orion Nebula, situated just below the three stars and seen as a fuzzy white patch with the naked eye, provides an amazing view with binoculars. One should be able to discern the nebulosity and make out the bright specks of light, which are newly-forming stars.
Orion is extremely helpful in finding other constellations. We can find two zodiacal constellations by drawing an imaginary line through the constellation’s major stars: Gemini can be traced by drawing a line joining the two brightest stars of Orion: from Rigel at the bottom right corner of the constellation, all the way through to Betelgeuse, found at the top left corner, and continuing along this line till we come by the two bright stars of the twin brothers Castor and Pollux, while Taurus can be found by following the three stars marking Orion’s belt and moving along an imaginary line to the right till we reach a bright scarlet star, Aldebaran, marking the bull’s eye.
There are in fact many other interesting objects in the January sky. And yet Orion is so spectacular, so laden with interesting objects that it is enough to captivate anyone’s interest.
Betelgeuse is a bright star, yellowish in appearance, and marks the Hunter’s right shoulder. It is a huge star, its diameter being larger than Mars’ orbit. Rigel marks Orion’s left knee and is the brightest star in the constellation.
The region of Orion’s Belt makes for wonderful sky sweeping with binoculars, as these reveal a multitude of stars. A number of the constellation’s stars can be seen as double using binoculars, and two of them can be found here. Both Mintaka and Alnitak, the two outer stars of Orion’s Belt, are in fact double stars.
Finding these and other noteworthy objects in Orion is particularly rewarding, but a leisurely sweeping of this magnificent constellation is also very satisfying.
Orion is visible in the night sky from October to March.
We’ll now make use of the technique of star-hopping, which basically is finding your way around the sky by hopping from one constellation to another, by using them as reference. As already noted, Orion is ideal for this as it points the way to a number of constellations.
As we have already seen, we can find Gemini by finding Rigel and drawing an imaginary diagonal line crossing the whole of Orion to Betelgeuse. Now continue with that line until you reach two stars: these are Castor and Pollux, the twins. We have just star hopped from one constellation to another, namely from Orion to Gemini. (For more information on how to star hop, including an informative visual tutorial, visit: http://www.astrocentral.co.uk/starting.html)
In Greek mythology Castor and Pollux were the twin sons of the Spartan Queen Leda and the king of gods, Zeus (though according to other versions of the myth Castor’s father was Tyndareus, king of Sparta), and brothers of Helen of Troy. Castor was killed by his cousin Idas as a result of an argument over some meat (they certainly took things seriously back then), who in turn fell victim to a thunderbolt hurled by a furious Zeus, whereas Lynceus, Idas’s brother was killed by Pollux. Zeus placed the twin brothers among the stars and they became the constellation Gemini, with the two brightest stars bearing their names: Pollux is the slightly brighter star, above it lies Castor.
Gemini is not a very interesting constellation for naked-eye observers, though it holds wonders for those equipped with a telescope. Castor, for instance, is in reality a multiple star system comprising of 6 stars, three of which can be resolved in small telescopes.
M35 is a cluster that can be found at the opposite end of the constellation, slightly above Eta Geminorum, and is a spectacular view in binoculars. M35 is a magical cluster, as stars seem to miraculously appear from nowhere the longer you look at it.
The Eskimo Nebula is another celestial jewel that this constellation offers to those availing of telescopic sight. It is unfortunately too faint to be seen in binoculars.
Try to familiarize yourself with these two constellations and Orion in particular, since it will prove to be a useful signpost for finding other constellations. The sky should already be taking some form with knowledge of these new distinguishable patterns of stars, and you should already feel better orientated when looking at the heavens. Next time we’ll take a look at another two interesting constellations.
