Sky Watch: September 2017

What to See in the Night Sky

By Bob Berman
August 31, 2017
Universe at Night

Welcome to the September 2017 Sky Watch!  See what to look for in the night sky tonight, including visible planets, the full Moon, and more celestial highlights!

Sky Watch September 2017

by Bob Berman, as featured in The 2017 Old Farmer’s Almanac
(Note: Times listed below are ET.)

What’s in September’s night sky? Here are the highlights:

  • Neptune comes to opposition on the 5th in Aquarius, but a telescope is needed to see its disk and blue color.
  • On the 10th, Mercury at magnitude zero closely meets Leo’s main star, Regulus, with Venus far above.
  • Also in the predawn sky, Mercury and Mars almost touch on the 16th, but the pair is only 8 degrees high in twilight.
  • The morning of the 18th brings a super lineup some 40 minutes before sunrise, with Mercury lowest; dim, orange Mars to its upper right; the crescent Moon; Regulus; and finally Venus at the highest point of the quintet. The next morning, the Moon is below Mercury.
  • Autumn starts with the equinox on the 22nd at 4:02 p.m. See our Autumnal Equinox page!

See a free sky map to navigate September’s night sky.


The 2017 Old Farmer's Almanac

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