Admittedly, June is not astronomers’ favourite month. Its short nights curtail the effort and energy required for the observation of faint celestial objects, which is quite time-intensive. We must therefore focus on the Moon and other bright objects. Fortunately, the planets occupy a choice position in the sky this month.
Jupiter at twilight
Jupiter currently dominates the western horizon at sunset. The giant planet is so bright it can easily be seen shining in the twilight below Castor and Pollux, the two brightest stars of Gemini. In case of doubt, a thin lunar crescent will appear to the planet’s left on the evenings of June 1 & 29.
Jupiter is a fascinating target for telescopes — even modest ones. Its four Galilean moons immediately stand out, and a close examination of the planet’s disk reveals the parallel, light and dark atmospheric cloud bands, which circle the Jovian globe.
Another atmospheric feature that is somewhat harder to see is Jupiter’s famous Great Red Spot. A comparison of past and present measurements of this anticyclonic vortex indicates that it has been steadily shrinking since the 1930’s. At present, its size is decreasing by 900 km per year; right now, its diameter measures about 16 500 km — slightly larger than Earth. Meanwhile, its shape, which was oval, is becoming increasingly circular. Will Jupiter’s Great Red Spot eventually disappear? Better hurry and observe it while you still can!
Mars and Saturn rule the night
As Jupiter sets beneath the western horizon, our attention turns to Mars and Saturn, which can be observed for much of the night in the southwest and south, respectively.
At the end of May, Mars resumed its direct eastward movement among the stars of Virgo. Pay close attention to the gap between Mars and Virgo’s brightest star, Spica: That gap diminishes rapidly as the Red Planet passes the blue-white star on July 14. Though not as bright as Jupiter, Mars is easy to spot thanks to Spica and the gibbous moon, which appears nearby on the evening of June 7.
Saturn is even less bright than Mars and Jupiter but, like Mars, it’s easy to identify thanks to the nearly-full moon, which appears beneath the ringed planet on the evenings of June 9 & 10. Spica in Virgo, and Antares in Scorpius, also serve as guides: Saturn is situated mid-way and slightly above a line connecting the two bright stars.
Through the eyepiece of a small telescope Saturn’s beauty can really be appreciated: The planet’s magnificent rings offer a spectacle unequalled in our solar system. Along with the Moon, Saturn is on the list of “must-see” objects for beginners and seasoned observers alike. Take advantage of warm summer evenings and pay Saturn a visit.
Venus at dawn
Venus is so bright you’ll have no trouble locating it above the east-northeast horizon before sunrise. This dazzling planetary gem will be even more spectacular on the morning of June 24 when a thin lunar crescent will add to the celestial setting: Get ready to take some outstanding photos.
In closing, the summer solstice will occur on June 21 at 6:51 A.M. (EDT): This is when summer officially gets underway in the Northern Hemisphere. On this date, the Sun will move from Taurus into Gemini, crossing the border between the two constallations. And finally… June 29 marks the beginning of Ramadan in the Muslim lunar calendar.