- Planétarium Rio Tinto Alcan
From September 11 to 25, 2017
Mercury is presently visible at dawn, low in the east, 30 minutes before sunrise. The tiny planet is at greatest elongation on September 12, 18 degrees West of the Sun; it then begins to sink back toward the Sun, but Mercury is still brightening and remains fairly easy to see with the naked eye until the last week in September. On the morning of September 18, the thin lunar crescent will rest between Mercury and dazzling Venus higher above.
Venus is the bright Morning Star, shining above the eastern horizon at the end of the night and at dawn; Venus rises more than 2 hours before the sun. On the morning of September 17, the thin lunar crescent will rest 7 degrees above Venus, and just 4 degrees below the dazzling planet the following day.
Mars is slowly emerging from the sun’s glare and gradually reappears in the morning sky: binoculars will help you locate it at dawn, 30 minutes before sunrise, very low above the east-northeast horizon. From September 11 to 19, let much brighter Mercury guide you to Mars, as the two planets appear less than 3 degrees apart; minimum separation, barely more than ¼ degree, occurs on September 16.
Jupiter is sinking in the sun’s glare and appears lower and lower in the sky after sunset. The bright planet comes into view at dusk barely 5 degrees high in the west-southwest, and then gradually descends toward the western horizon where it vanishes before 8 p.m.
Saturn appears at dusk, some 20 degrees above the south-southwest horizon, and vanishes in the southwest after 10:30 p.m. The crescent moon will hang less than 3 degrees above the Ringed Planet on the evening of September 26.