Neptune pokes above the eastern horizon around 10 p.m. local daylight time in early August and during twilight by month’s end. It climbs high enough by midnight to track among the background stars of eastern Aquarius. You’ll need binoculars or a telescope to see the magnitude 7.8 planet. Luckily, a 4th-magnitude star nearby can guide you. Phi (ϕ) Aquarii lies 0.9° west-southwest of Neptune on August 1, and the gap shrinks to 0.15° by the 31st. Don’t confuse the planet with a magnitude 7.5 star in the same vicinity. A telescope can confirm your identification — only Neptune shows a distinct disk, which spans 2.4" and appears blue-gray.
The early morning hours are the best for viewing Uranus. Although the planet rises before midnight local daylight time, it doesn’t climb highest in the south until near the break of dawn. Uranus shines at magnitude 5.8, bright enough to see with the naked eye under a dark sky but much easier to find through binoculars.
The ice giant resides in a sparse region of southern Aries, 11° south and a hair east of the Ram’s brightest star, 2nd-magnitude Hamal (Alpha [α] Arietis). Two magnitude 5.7 stars help blaze the way. Drop 4.0° south of Hamal to 15 Ari, then another 4.3° south to 19 Ari. Uranus lies 2.3° south-southeast of this final star. And because the planet reaches its stationary point the night of August 11/12, it doesn’t move much from this spot all month. A telescope reveals Uranus’ distinctive blue-green disk, which measures 3.6" across.
Mercury enjoys a nice but brief appearance before dawn this month. The inner planet reaches greatest elongation August 9, when it lies 19° west of the Sun and rises 90 minutes before our star. It climbs 7° high in the east-northeast 45 minutes before sunrise. The magnitude 0.0 world shines noticeably brighter than the twin stars of Gemini, Castor and Pollux, which lie higher and point in Mercury’s direction. The planet becomes even easier to see as it brightens noticeably in the week that follows. On the 17th, it shines at magnitude –0.9 and appears 6° high 45 minutes before sunup. It soon drops out of sight, however, as it heads toward superior conjunction in early September.
It’s also worth taking a few minutes to target Mercury with your telescope. The best views come on the morning of greatest elongation, when the planet appears 8" across and barely one-third lit. By August 17, its diameter has shrunk to 6" and its phase has waxed to two-thirds lit.
Venus and Mars lie too close to the Sun to see during August. Both planets will return to view in October — Venus at dusk and Mars before dawn.