Venus and Jupiter, the magnificent planetary duo that’s been visible for the last few months, will be joined by two more objects that are familiar to astronomers. Around the beginning of the month, the discreet planet Mercury will appear along with Venus and Jupiter at twilight; then later in the evening, the ever-popular planet Saturn will join the duo.
Venus dominates the evening
The star of this month’s planetary tetrad, Venus, dominates the twilight sky with its brilliance. The planet can be found about thirty degrees above the western horizon at sunset and remains visible for a few hours thereafter. Through a telescope, Venus exhibits phases similar to the Moon; this month, the dazzling planet evolves from gibbous to crescent. For those in doubt that they have actually identified Venus, a thin crescent moon will appear close to the planet at sunset on May 21 and 22.
Jupiter, the forgotten co-star
Though less brilliant than Venus, Jupiter is also easy to see this May at nightfall. The giant planet is currently located on the eastern border of Cancer, which it leaves when it heads into Leo after the first week of June. A crescent moon will appear near Jupiter on the evenings of May 23 and 24.
Like Venus, Jupiter merits some attention, especially if you own a small telescope: The planet’s apparent diameter is twice that of its brighter cohort. Without doubt, the light and dark cloud bands that encircle the Jovian globe are impressive to observe; not to mention the four Galilean moons that can be seen moving in orbit about the planet over the course of a few nights. Overall, a truly colourful celestial show!
Throughout May, if you pay close attention to both planets shining in the twilight, you’ll notice that Venus and Jupiter are slowly converging. A spectacular planetary rendezvous is in the works for June 30. More about that next month…
Saturn, the rising star this summer
Currently undergoing its retrograde loop on the border of Scorpius and Libra, Saturn arrives at opposition on May 22. At that point, the ringed planet will be visible all night, rising in the southeast at sunset and disappearing in the southwest at dawn. The full moon will accompany Saturn on the evening of May 4 and again, one lunar cycle later, on June 1.
Unfortunately, Saturn is currently in a region of sky that never rises very high above the horizon. Telescopic observations of the planet are therefore hampered by atmospheric turbulence, not to mention the need for a horizon that’s perfectly clear and obstacle-free.
Despite these hindrances, the sight of Saturn’s rings, currently inclined about 25 degrees toward Earth, is well worth a look. More so, considering that Saturn will dominate the sky this summer, and will be easily visible in the south-southwest at twilight. A perfect opportunity to invite friends to discover this magnificent planet in your company!
Mercury, a discreet presence
Mercury is normally difficult to spot, but at the beginning of May the tiny planet undergoes a favourable apparition in the twilight sky. It can be located using binoculars thanks to the Pleiades cluster, which is located to the planet’s lower right. On May 7, Mercury reaches its greatest elongation east of the Sun. Thereafter, the furtive planet will quickly move sunward until it becomes lost in the solar glare.
Like Venus, Mercury also exhibits phases when seen through a telescope; a crescent Mercury will be visible during the first week of May. Be careful when pointing your telescope toward the tiny planet, especially around sunset: The Sun and Mercury are never far apart!
Clear skies to all!
See also
Planets visible to the naked eye
