At nightfall tonight and tomorrow – October 5 and 6, 2016 – watch for the waxing crescent moon near the planet Saturn in the evening sky. Then, on October 7, the moon will be near Mars.
Saturn, a golden world to the unaided eye, is everyone’s favorite planet to view through a telescope due to its wide, encircling rings. Just go outside as soon as the sun goes down and look for the moon. The moon will be in the general direction of sunset – to the left of the sunset as seen on these Northern Hemisphere autumn evenings – and above the sunset as seen from the Southern Hemisphere, where it’s now springtime.
Very simply, Saturn is the brightest starlike object near the moon on October 5 and 6. The only celestial body that might be confused with Saturn is a reddish star – Antares in the constellation Scorpius.
This star represents the Scorpion’s Heart. Antares will likely appear more reddish in color than Saturn, and it will likely be twinkling furiously. It’s true that stars twinkle, while planets shine steadily, and Antares is known as a great twinkler.
Saturn, the sixth planet outward from the sun, is the most distant world that you can easily see with the unaided eye. Saturn shines most brilliantly in our sky in a year when Saturn’s rings are widest open – and, additionally, when Saturn sweeps to perihelion – nearest point to the sun in its 29.5-year orbit. At perihelion, Saturn is one astronomical unit (AU) closer to the sun than when it’s at aphelion – its most distant point.
Saturn’s most brilliant appearance in our sky last happened during the opposition of December 31, 2003, and will next happen at the opposition of December 24, 2032. At these very favorable oppositions, Saturn resides 9 AU from the sun and 8 AU from Earth.
Next year, in 2017, the rings will be widest open. However, the year 2017 also finds Saturn at the vicinity of aphelion, at 10 AU from the sun and 9 AU from Earth during the opposition of June 15, 2017. Even so, Saturn will be respectably bright in 2017. The maximum tilt of Saturn’s very reflective rings toward Earth is a larger contributor to Saturn’s magnitude than its closeness to Earth.
By the way, before darkness falls, look for the sky’s brightest planet – Venus – near the sunset point on the horizon. You’ll want to look no later than about 45 to 60 minutes after the sun goes down.
This dazzling planet will set by nightfall or early evening, while the moon and Saturn will stay out for an hour or two after Venus sets (depending on your latitude). Click here for a sky almanac. The chart below shows Saturn and the moon on October 5, in relationship to Venus and a nearby moderately bright star …
Bottom line: The young moon will be sweeping past Saturn for the next few evenings. Watch for it after sunset, especially on October 5 and 6, 2016.