Posted by on Apr 27, 2023 in Main |

The May night sky 2023

Venus and Mars grace the western sky, while the southern part of the heavens is dominated by the brilliant orange star Arcturus. Well to its lower right, are the blue-white stars Spica and Regulus. But the region to the left of Arcturus boats only the faint stars of two giant constellations, Ophiuchus and Hercules.


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.


The innermost planet reaches its greatest separation from the Sun on the 29th of May however Mercury will be lost in the sun’s glare and will be unsuitable for observation this month.

The evening star shines brightly in the western sky this month begins, not setting below the horizon until after midnight. At magnitude Venus is far brighter than anything else in the evening sky expect the Moon. If you are fortunate to find a really dark location away from streetlights and moonlight and you let your eyes adapt to the dark you may be able to make out shadows cast by the light of Venus. The Moon forms a striking combination with Venus and adjacent stars Castor and Pollux on the 22nd and 23rd of the month.

The red planet lies well to the upper left of Venus, firmly but in its place by the flashier evening star. At magnitude +1.5 it is almost 200 times fainter than Venus. Mars will be falling below the horizon about 1.30am. It starts the month in the constellation of Gemini. It passes the stars Castor and Pollux around the 10th May. It then moves into the constellation of Cancer, where Mars has a close encounter with the moon on the 24th of the month.

The gas giant reappears low in the morning sky mid month. Jupiter rises around 4am, and shines brightly on the borders of Pisces and Aries, at magnitude –2.1. The crescent Moon is nearby on the morning of the 17th.

The ring world rises above the horizon around 3am. Located in the constellation of Aquarius, Saturn shines at magnitude +1.0. On the mornings of 13th and 14th of May the crescent Moon passes below Saturn.

This distant world will be too close to the Sun for observation this month.

Dim Neptune at magnitude +7.9 can be located in the constellation of Pisces. Rising above the western horizon around 3.30am.

Can be found in the constellation of Capricornus. It will always be low down in the west and only visible in a ten-inch or larger telescope in a truly dark sky for a short period of time. Pluto rises above the horizon about 3.45am and has a magnitude of +14.4.

The largest object in the asteroid belt can be located in the constellation of Coma Berenices this month. At Magnitude +7.28 it sets just around 11.30pm.

Special Events:-

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 predicted to be unusually intense this year, but sadly bright moonlight will spoil the show.

On 22nd and 23rd May the thin crescent Moon hangs to the lower right of a brilliant Venus. with the twin stars of Gemini Castor and Pollux nearby

Phases of the Moon :-

Full Moon 5th May
Last quarter 12th May
New Moon 19th May
First quarter 27th May