At the start of August from southern and tropical latitudes the planets Mercury, Venus and Jupiter are all visible low down above the western horizon just after sunset. The brightest planet is Venus (mag. -4.1) followed by Jupiter (mag. -1.7) with Mercury the faintest (mag. -0.6). During the first 10 days of the month the three planets will "dance" above the horizon, offering a slightly different view each subsequent evening. After this, Venus and Jupiter will be lost to the bright twilight sky but Mercury will improve in altitude for some days, remaining visible well into September.
The diagram below shows the evening apparition of Mercury, Venus and Jupiter from Sydney, Australia at latitude 35S. Positions are displayed 45 minutes after sunset. Note the position of the planets will be slightly different when viewed from varying southern or tropical latitudes / longitudes.
On August 7th, a rare conjunction occurs when Mercury passes only 0.6 degrees north of Jupiter; a distance just slightly greater than the full Moon diameter. The giant planet Jupiter appears one magnitude or 2.5 times brighter than the much smaller but closer Mercury. Through binoculars the pair will form a fine early evening sight low down above the western horizon just after sunset. Adding to the view is brighter Venus about 6 degrees to the south. The diagram below shows the planets 45 minutes after sunset from Sydney, Australia (latitude 35S). Again the position of the planets will be slightly different when viewed from varying southern or tropical latitudes / longitudes.