Southern Hemisphere night sky guide September 2017

NOTE: This guide is written for southern hemisphere observers. Much of the content is still relevant for those in the northern hemisphere, however, the precise time and location in the sky will vary to those noted.

Observing Highlights

  • 5th    – Neptune at Opposition
  • 18th  – Moon and Venus closest in the morning
  • 19th  – Moon, Mars and Mercury close in the morning
  • 20th  – Venus and Regulus closest in the morning
  • 22nd – Moon, Jupiter and Spica close in the evening
  • 23rd  – Spring Equinox


Mercury graces the eastern, morning sky this month and will best be viewed just above the horizon around the 12th. It will be extremely close to Mars on the 17th, and the pair will be joined by the crescent Moon on the 19th, however, proximity to the horizon and the Sun make for challenging observations.**

Venus can be found shining brightly in the eastern, predawn sky. The highlight for this month comes when Venus will be occulted by the crescent Moon on the morning of the 18th. Ingress will be a little after 10:30 AM (AEST), and Venus will reappear from behind the shadowed portion of the Moon just after midday.**

Earth will be at spring equinox on the 23rd of this month. On this day, the Sun will rise due east and set due west, with the lengths of day and night being equal.

Mars reappears around mid-month, after its passage behind the Sun. As mentioned above, it makes a close pass by Mercury**, before gradually making its way higher in the sky over the following weeks, and approaching Venus as the month ends.

Jupiter spends the first half of this month in relatively close proximity to the bright star, Spica. On the 22nd, the widening pair will be joined by a slender, crescent Moon, which will make for a pleasant conjunction towards the western horizon just after sunset.

Saturn can be found high in the evening sky again this month. Perhaps the best night to observe the ringed planet will be on the 14th when it reaches its eastern quadrature. In this position, where the Sun-Earth_saturn angle is 90°, the shadow of the planet on the rings behind will reach its greatest extent, adding great depth to the already-impressive spectacle.

Uranus can be found in the constellation of Pisces this month, rising at around 9 pm as September begins, and 7 pm by month’s end. It is around 4° from the gibbous Moon on the 10th.

Neptune reaches opposition on the 5th of this month, but despite this, it still appears no brighter than about 8th magnitude. Observations are best left until around New Moon, though even larger telescopes will likely resolve any more detail than a tiny, pale blue disc.

** Observations close to the Sun should not be attempted by inexperienced observers! Instant and permanent blindness can occur as a result of small errors. For increased safety, the Sun should be obscured by a structure.

The Moon

Full Moon

September 6th .svg

Last Quarter

September 13th

New Moon

September 20th*

First Quarter

September 28th


September 27th

404,348 km


September 14th

369,860 km

 * The best time for viewing the Milky Way, Nebulae, Galaxies, and other faint objects is around this date


  • 18th  –  Moon and Venus (morning)
  • 19th  –  Moon, Mercury, and Mars (morning)
  • 20th  –  Venus and Regulus (morning)
  • 22nd –  Moon, Jupiter and Spica (evening)


  • 12th, 1300 UTC  –  Aldebaran occulted by the Moon. Visible from Hawaii and Azores
  • 18th, 0100 UTC  –  Venus occulted by the Moon. Visible from Asia, Australia and New Zealand
  • 18th, 0500 UTC  –  Regulus occulted by the Moon. Visible from Africa, Middle East, Asia and Australia
  • 18th, 2000 UTC  –  Mars occulted by the Moon. Visible from Hawaii and South America
  • 18th, 2300 UTC  –  Mercury occulted by the Moon. Visible from Asia, Pacific Islands.

Bright Comets




C/2017 O1 (ASASSN)Taurus~7th
C/2015 V2 JohnsonNorma~10th

Meteor Showers

  • No major meteor showers


The constellation of Capricornus - The Sea Goat

“The Sea Goat”: Capricornus is the smallest of the constellations in the zodiac, and is represented by a bizarre, mythical creature that is half goat, half fish.

Brightest Star: Deneb Algedi (Delta Capricorni)

The constellation of Cygnus - The Swan

“The Swan”:  Soaring along the plane of the Milky Way, Cygnus contains the bright asterism known as “The Northern Cross”.

Brightest Star: Deneb

The constellation Dephinus - The Dolphin


“The Dolphin”: Delphinus was named by the astronomer Ptolemy in the second century and lies in the northern sky, close to the celestial equator.

Brightest Star: Rotanev (Beta Delphini)

The constellation of Equuleus - The Little horse


“The Little Horse”: Equuleus is a small, faint constellation spanning only 72 square degrees – making it second smallest after Crux (The Southern Cross).

Brightest Star: Kitalpha (Alpha Equulei)

The constellation of Indus - The Indian


“The Indian”: The constellation Indus first appeared in Johann Bayer’s “Uranometria” in the year 1603.

Brightest Star: Alpha Indi

The constellation Microcopium - The microscope


“The Microscope”: One of the modern constellations named after scientific instruments by French astronomer Nicolas Louis de Lacaille in the Eighteenth Century.

Brightest Star: Gamma Microscopii

The constellation of Vulpecula - The Little Fox


“The Little Fox”: Vulpecula is a small constellation that lies in the heart of “The Summer Triangle” – an asterism in the northern sky formed by the bright stars Deneb, Vega and Altair.

Brightest Star: Alpha Vulpeculae