Astronomy Info & Events: September

Moon Phases

September 2: Last Quarter Moon

September 9: New Moon

September 16: First Quarter Moon

September 27: Full Moon (the Harvest, Fruit or Corn Moon)

Special Events

Comet 21P/Giacobini-Zinner is visible through a telescope and binoculars this month and moves through the constellations of Auriga, Gemini and Monoceros during the month. This comet may become a naked eye comet by September at magnitude 6.

International Space Station (ISS) Observable Passes

ISS passes are visible during the early morning hours early in the month, shifting to the late evening hours during the latter part of the month. Check out the website or by using satellite tracking smart phone apps like Sputnik to find out the exact times when the ISS will be visible from your location. The ISS will be seen as a bright moving point of light, moving in an arc from the west to the east during its visible passes.

September 1 & 2: Beaver Hills Dark Sky Festival.  Activities at Elk Island Provincial Park. Activities include workshops, telescopic observing (day and night), presentations, family activities and more.

September 2 & 3: Comet Giacobini-Zinner (Comet 21P) will be 2 degrees from Capella (dawn sky)

September 4-9: Northern Prairie Star Party, near Tofield, AB. See

September 7: Neptune at opposition

September 10: Royal Astronomical Society of Canada (RASC) Edmonton Centre meeting 7:30 – 9:30 p.m. in the new Zeidler Dome at the TELUS World of Science. Free to attend. See for more details

September 21: Venus at its greatest brightness in the evening sky!

September 22: Autumnal Equinox occurs at exactly 7:54 p.m. MDT (First day of fall).

Visible Planets

Mercury can be found low above the east-northeast horizon for the first few days of the month disappearing into the glare of the rising Sun during the second week of the month. Before sunrise on September 8, look for Mercury below the very slim waning crescent Moon.

Venus is lost in the glare of the Sun from our latitude this month and will not be visible.

Mars is found in the southeastern sky at sunset and shines with a bright orange glow. It then moves westward as the night progresses, reaching its highest altitude in the southern sky of only a little over 10 degrees around 11:00 p.m. local time. Mars then sets by 2:00 a.m. in the southwest. During the month you can watch Mars fade in brightness as the distance between Mars and Earth increases.

Jupiter can be seen in the southwestern sky after sunset, setting along the southwestern horizon a few hours later. Jupiter continues its presence amongst the stars of the constellation of Libra, the scales, with the waxing crescent Moon located above Jupiter on the evening of September 13.

Saturn is found low in the south-southwestern sky at sunset this month, setting about two hours later in the southwest. Saturn is located in the constellation of Sagittarius, the archer. On the night of September 17 the waxing crescent Moon can be seen just above Saturn.