May is the first month when the constellation of Orion is absent from the night sky altogether, and of the prominent winter stars only Capella in Auriga the Charioteer and Castor and Pollux in Gemini remain above the western horizon. The Plough or Ursa Major (the Great Bear) is still more or less overhead with the pointers pointing to the North Star. The ‘W’ of Cassiopeia is now very low down although still easily visible in the north western sky.
It is also a good month to look for another of the circumpolar constellations; Draco the Dragon. Circumpolar constellations such as the Plough, Cassiopeia and Draco are visible all year around; this is because these stars are above the Earth in space.
Draco is represented by a stream of stars that winds its way around the North Star, so although it has no really bright stars it is still quite easy to identify. The stream starts roughly between the pointers of the Plough and the North Star, then winds its way past the Plough making off in the general direction of Cepheus.
It then turns and ends up at the ‘Dragon’s Head’, a quadrilateral of four stars near the bright star Vega, which is one of the stars that forms the Summer Triangle.
There is one notable star to mention in Draco and this is Thuban, which is not prominent in brightness and is located between Mizar, in the Plough, and the orange star Kocab, in Ursa Minor.
Use the Plough, to draw a line down following the curve of the handle to the bright orange star Arcturus in Bootes the Herdsman which is now very high up. Your downward curve will take you to Spica in Virgo the Virgin. Both Arcturus and Spica are almost due south.
High in the South West can be found Leo the Lion with its bright star Regulus, at the base of a distinctive looking ‘backwards question mark’ of stars. The small quadrilateral of stars that form Corvus the Crow is still quite conspicuous low in the south, while further to the south west and low down is the orange star Alphard, the brightest star in the constellation of Hydra the Water Snake. Alphard is often called ‘The Solitary One’ because of the lack of bright stars near it.
In the North East, two of the stars that form the summer triangle can be seen; Vega, in Lyra the Lyre, has reached a respectable altitude and Deneb in Cygnus the Swan is now becoming noticeable. The third point in the triangle, Altair in Aquila the Eagle, has yet to appear.
This month belongs to the King of the Planets, Jupiter which can be located in Virgo to the right and slightly above Spica; there is little chance of confusion as Jupiter is so very much brighter than Spica that it is difficult to miss. In fact, the only planet brighter than Jupiter is Venus. Jupiter will have a couple of close encounters with the Moon this month. On May 7th the Moon will be directly above Jupiter while the following evening, May 8th, the Moon will be above and to the left of Jupiter.
If you have binoculars, use them to look at Jupiter because on May 7th and 8th it is possible to see the four big moons of Jupiter that were discovered by Galileo in 1610. On the 7th May, in order from the left, through your binoculars you will see Callisto, Europa, Io, Jupiter, and Ganymede. On the 8th again from the left you will see Callisto, Jupiter, Io, Europa, and Ganymede. This is not always possible as sometimes the moons can be in front of, or behind Jupiter, making them impossible to see.
Saturn does not rise until about midnight and even then is low down in the south eastern sky, while Venus rises just before sunrise but is difficult to see and Mars is equally difficult to see because it is low in the west in the evening twilight, Mercury is still too close to the Sun to be seen in the May sky.
There is one meteor shower this month, called the Eta Aquarids. This shower, which will peak in the early hours of the mornings of May 5th and May 6th, is best seen from the southern hemisphere; however, on either of those mornings a couple of hours before sunrise you might see around 10 meteors per hour. This meteor shower is the remains of Halley’s comet.
Phases of the Moon for May
First Quarter 3rd
Full Moon 10th
Last Quarter 19th
New Moon 25th