This month is full of celestial action, though you will have to be an early bird to see it all. The highlights are a close conjunction of Jupiter with Venus and Mars. A total lunar eclipse. Mercury with the Pleiades. Meteors from Halley’s Comet, and possibly a storm of shooting stars at the end of the month.
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.
Mercury – On the evening if 1st May Mercury lies just to the left of the Pleiades, and the following night they are joined by a narrow crescent Moon. The innermost planet shines at magnitude +0.7, just slightly brighter than Aldebaran to the left. Setting about 10pm, Mercury fades rapidly as the month progresses, and disappears into the twilight glow by the middle of the month.
Saturn – The next planet that’s visible, rising in the south-east around 2.30am. Ay magnitude +0.8, the ringed planet is to be found in Capricornus.
Venus and Jupiter– Just before dawn, an intriguing planetary dance takes place during May. Venus, the brightest of these worlds, at magnitude –4.0 rises above the horizon about 4am. On the morning of 1st May Venus will be close up and personal to the second most brilliant planet, as Venus passes below Jupiter at a distance of just 20 archminutes. At magnitude –2.1, the gas giant resides in Pisces all month. It rises around 3.30am in the middle of the month.
Neptune – Lies to the right of Jupiter, right on the border of Pisces and Aquarius. Also rising about 3.30am. The most distant planet shines at a feeble +7.9 magnitude.
Mars – At the start of May you will locate the red planet well to the right of of Jupiter and Venus in the centre of Aquarius. As the month progresses, Mars at magnitude +0.8 moves rapidly to the left and into Pisces. It passes Neptune on the 18th May. It’s just 40 arcminutes from a much brighter Jupiter on 29th May. Both planets are climbing above the horizon around 3.30am.
Uranus – Is too close to the sun for observation this month.
Halley’s Comet reappears this month!. well not the actual beast, but dirt from its skirt which burns up above our heads as a shower called the Eta Aquarids. This shower, which will peak in the early hours of the morning May 6th, is best seen from the southern hemisphere.
On the night of 31st May into 1st June, debris from comet Schwassman-Wachman 3 may produce a storm of shooting stars. The Tau Herculid meteor shower has now moved to the constellation of Bootes. The peak of the display is expected just before dawn.
On 16th May there is a big and bright supermoon. Together with a total lunar eclipse visible in America and parts of Africa and Europe. From this part of the world, the partial phase starts at 3.27am and totality at 4.29am.
Phases of the Moon :-
First Quarter 9th
Full Moon 16th
Last Quarter 22nd
New Moon 30th