Planet trio

June 23-29 – Planet trio. The three planets that will cluster to within 5º of each other, low in the west-northwest evening twilight are Venus (magnitude –3.9), Saturn (+0.2) and Mercury (-0.2). Between June 23 and 29, these three will fit within a circle measuring just 5º across, the smallest circle (1.4º) occurring on June 26. As such, their rapidly changing night-to-night positions relative to one another should be most fascinating to watch. Individual conjunctions include Venus and Saturn (1.3º on June 25), Mercury and Saturn (1.4º on June 26), and Mercury and Venus (a mere 0.1º on June 27). A drawback for observers will be that these three planets will be visible for at best for only about an hour after sundown before they start getting too low to the horizon to be readily observable. Also during this time frame, take note of the "Twin Stars," Pollux (+1.2) and Castor (+1.6) of Gemini, which will be positioned roughly 6 to 10º above and to the right (west-northwest) of the trio