Current Night Sky: September 2018

The September Equinox occurs at 9:54 pm EDT on September 22. This represents the instant the Sun crosses the celestial equator on its way south. By convention, it is considered the beginning of autumn in the northern hemisphere and of spring in the southern hemisphere.

The Moon & Planets: 
Neptune

Neptune reaches opposition on September 7. It lies opposite to our Sun in our sky, so rises at sunset, stays up all night, and sets at sunrise. It is also at its closest to Earth – 2.7 billion miles away. That's not saying much; from that distance it takes light 4 hours to reach us. Even though the planet is almost 4 times the diameter of Earth, it appears no larger than 2.3 arc-seconds across and only reaches magnitude 7.8 in brightness – far below naked-eye visibility. In a modest telescope, it looks barely distinguishable from a star (September 7, 2018; 2:27 pm EDT).

Mars, Saturn, Jupiter, and Venus

Four planets – Mars, Saturn, Jupiter, and Venus – are lined up for our viewing pleasure on September evenings. In mid-month, a waxing Moon joins them. A half-hour after sunset, a smattering of brighter stars are visible. (September 15, 2018; 7:22 pm EDT).

At the autumn (or September) equinox (globe in left foreground), the Earth is experiencing equal amounts of sunlight in each hemisphere. Afterwards, the Southern Hemisphere begins to get more sunlight, leading to winter in the Northern Hemisphere (September 22, 2016, 9:54 pm EDT).

Evening Planets (after sunset): 
  • Venus, SW
  • Jupiter, SW
  • Saturn, S
  • Mars, S
  • Neptune, E
Morning Planets (before sunrise): 
  • Neptune, W
  • Uranus, SW
  • Mercury, E
Comets: 

There are no comets brighter than magnitude 8 visible this month.

Meteors: 

There are no major meteor showers in September.

Phases of the Moon: 
Last Quarter Moon September 2 10:37 pm EDT
New Moon September 9 2:01 pm EDT
First Quarter Moon September 16 7:15 pm EDT
Full Moon September 24 10:52 pm EDT

Text, graphics, and animations by John Sheff. Graphics courtesy of Starry Night(©) Pro Plus 7 / Imaginova(©) Corp. Starry Night images are used with permission from Imaginova Corp. Starry Night is a registered trademark of Imaginova Corp. Star charts generated by Starry Night Pro Plus 7 © Imaginova Corp. All rights reserved. www.StarryNight.com