Planets visible to the naked eye
From July 16 to 30, 2018
Mercury, now fainter and fainter, vanishes in the glow of sunset during the third week of July. The tiny planet passes between Earth and the sun (inferior conjunction) on August 8 and gradually reappears at dawn a couple of weeks later.
Venus is the bright Evening Star that pierces the colours of twilight in the west, as soon as the sky begins to darken in the minutes after sunset. Venus is still pulling away from the Sun, but its orbit is tilting down on the horizon: as a consequence, Venus now sets less than two hours after our daytime star. At dusk on August 14, the lunar crescent hangs 6 degrees above Venus: with binoculars, admire the earthshine that dimly lights the otherwise dark section of the lunar disc. The scene becomes truly magnificent when the sky darkens, 30 to 45 minutes after sunset.
Mars is at opposition on July 27, which means it’s closer to Earth, larger and brighter than at any time in the past 15 years; for a few weeks, it even outshines bright Jupiter. Mars emerges above the southeast horizon at dusk, culminates around 1:30 a.m., barely 19 degrees high in the south, and vanishes in the southwest at dawn. Mars is presently performing its retrograde loop: until late August, it is moving westward (toward the right) with respect to the background stars. During the night of July 26 to 27 and 27 to 28, the full moon will shine near the Red Planet.
Jupiter appears above the south-southwest horizon during evening twilight and spends the rest of the evening slowly descending toward the west-southwest horizon where it vanishes after midnight. The waxing gibbous Moon shines 3 ½ degrees above Jupiter on the evening of July 20.
Saturn appears during evening twilight above the south-southeast horizon, culminates around 11 p.m. about 22 degrees high in the south, and then gradually descends toward the southwest horizon where it vanishes after 3 a.m. During the night of July 24 to 25, the waxing gibbous moon approaches within one degree from the ringed planet.