The Night Sky in May 2025
Jupiter is the early ‘evening star’. It appears in the northwest soon after sunset. It sets before 8 pm at the beginning of the month and soon after 6pm at the end. (So isn’t on the chart.) The Moon will be to the right of Jupiter on the 1st. Mars is the only other planet in the evening sky. It looks like an orange-red star low in the northwest, similar in brightness to nearby bright stars. The Moon will be near Mars on the 4th.
As the sky darkens Sirius appears midway down the western sky. It is the brightest true star and twinkles with all colours when setting in the southwest in the late evening. It is the ‘Dog Star', marking the head of Canis Major the big dog, now head down, tail up. Canopus, the second brightest star, is southwest of overhead. Below Sirius are bluish Rigel and reddish Betelgeuse, the brightest stars in Orion. Between them is a line of three stars, Orion's belt. To southern hemisphere star watchers, the line of three makes the bottom of 'The Pot', now tipped on its side.
Orange Arcturus is the brightest star in the northern sky, rising in the northeast at dusk. It often twinkles red and green when low in the sky. It is 37 light-years* away and about 120 times brighter than the sun.
Crux, the Southern Cross, is southeast of the zenith, to the right of 'The Pointers'. Alpha Centauri, the brighter Pointer, is the closest naked-eye star, 4.3 light years away. Beta Centauri, like most of the stars in Crux, is a blue-giant star hundreds of light years away. Canopus is also very luminous and distant: 13 000 times brighter than the sun and 300 light-years away.
Following the Milky Way down into the southeast finds Scorpius. Orange Antares marks the Scorpion's body. The scorpion's upside-down tail curves to the right of Antares. There is a Greek legend that the Scorpion and Orion were always fighting so a goddess put them on opposite sides of the sky, so they never appeared in the sky together. It doesn’t work for the southern hemisphere.
The Milky Way is brightest in the southeast toward Scorpius and Sagittarius. In a dark sky it can be traced up past the Pointers and Crux, fading toward Sirius. The Milky Way is our edgewise view of the galaxy, the pancake of billions of stars of which the sun is just one. The thick hub of the galaxy, 27 000 light-years away, is in Sagittarius. The nearby outer edge is by Orion where the Milky Way is faintest. A scan along the Milky Way with binoculars shows many clusters of stars and some glowing gas clouds, particularly in Carina and Scorpius.
The Clouds of Magellan, LMC and SMC, are midway down the southern sky, easily seen by eye on a dark moonless night. They are small galaxies. The Large Magellanic Cloud is 160 000 light-years away and the Small Cloud is around 200 000 light-years away. They are much smaller than our Milky Way Galaxy but there are many billions of stars in each.
Venus rises around 4 a.m. throughout the month, a brilliant object in the dark night sky. At the beginning of the month Saturn is a medium-bright ‘star’ above Venus. Mercury is a bright ‘star’ below Venus. Saturn moves higher in the sky morning to morning while Mercury slips lower. Venus stays put. By the end of the month Saturn is well above and left of Venus but is the brightest ‘star’ in that empty region. The Moon will be close to Saturn on the morning of the 23rd and close to Venus on the 24th. Around 9 a.m. on the 24th the crescent Moon will be due north and midway up the sky. Venus will then be about eight moon-diameters (4 degrees) above the Moon, giving a chance to find Venus by eye in the daylight.
Many meteors will be in the pre-dawn sky around May 5-7 as the Eta Aquarid meteor shower peaks. Up to 30 meteors per hour might be seen before twilight. The shower runs from late April to late May. The meteors are dust from Halley’s comet, hitting the air at high speed and burning up.
*A light-year (l.y.)is the distance that light travels in one year: nearly 10 million million km. Sunlight takes eight minutes to get here; moonlight about one second. Sunlight reaches Neptune, the outermost major planet, in four hours. It takes sunlight four years to reach the nearest star, Alpha Centauri.
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