Mercury reaches greatest elongation on June 15, placing the elusive planet at its farthest apparent distance from the sun in the evening sky. That makes this one of the best opportunities of the year to spot Mercury after sunset, shining below Venus and Jupiter in the western sky.
As an "inner" planet, Mercury never strays particularly far from the horizon compared to the outer planets like Mars and Jupiter, which shine brightly overhead from dusk to dawn at opposition, when they sit opposite the sun in Earth's sky.
