Dark sky view.

Eyes on the skies — September

Welcome to the Ontario Parks “Eyes on the skies” series. This series covers a wide range of astronomy topics with a focus on what can be seen from the pristine skies found in our provincial parks.

Many people consider September to be the finest month of the year to enjoy Ontario’s outdoors.

The bugs have all but left and the daytime temperatures are cooler, making the weather ideal for strenuous activities such as hiking or canoeing. To top it off, the leaves begin their beautiful transition through the colours of fall.

With the much shorter days, the nighttime skies are full of celestial splendours that we hope you will enjoy discovering in this edition of “Eyes on the skies.”

Here are our astronomical highlights for September, 2021:

The sun

The sun continues its apparent drop in elevation as it reaches Fall Equinox on September 22 at 5:22 pm.

This is most noticeable during the evening when, in mid-August, it seemed that there was quite some time between the end of dinner to twilight. Compared to the end of September, we are barely finished cleaning the dishes when twilight is upon us!

Lake beside forest with leaves changing colours all under a blue sky with bright sun

For those of us relying on daylight to paddle to that distant lakeside campsite or hike that last ridge before setting up for the evening, knowing when the sun sets is important.

Sunrise and sunset times

September 1 September 15 September 30
Sunrise 6:47 am 7:04 am 7:23 am
Midday 1:25 pm 1:28 pm 1:15 pm
Sunset 8:03 pm 7:36 pm 7:07 pm

The moon

The moon has long captivated observers of all ages. Even a pair of small binoculars will reveal the craters of the moon.

Photo of a full moon.

September’s lunar phases of the moon occur as follows:

lunar phases

Did you know many First Nations teachings, including those of the Anishinaabe and the Haudenosaunee people, use the back of a turtle’s shell as a lunar calendar? Learn more here.

The planets — the return of Saturn and Jupiter

Saturn and Jupiter continue to put on an impressive show.

By mid-month, Saturn is one of the brightest objects in the sky, due south at around 10:30 pm.

Jupiter is very prominent throughout the month and a spectacular object in a telescope or binoculars. It is due south around 11:30 pm mid-month and, if seen over water, casts a beautiful reflection amongst the stillness of the night.

Jupiter has as many as 80 moons or more, but the brightest four are spectacular and can be visible to the unaided eye if you know where to look and reduce the glare of Jupiter.

Simulated view of Jupiter and its four brighter moons
Simulated view of Jupiter and its four brighter moons (Jupiter is the biggest item in the centre)

These moons are great to see in a telescope, but even a good quality pair of birding binoculars will let you see them dance around Jupiter.

Because Jupiter rotates in 10 hours, you can watch them go at least a quarter of the way around Jupiter during the darker time of the year (late fall to early spring).

These four moons were discovered by Galileo Galilea in the early 1600s but have captivated scientists ever since.

Today, there is significant evidence to indicate massive amounts of liquid water may exist on two of these Galilean moons, Europa and Ganymede. Evidence suggests that Ganymede may have more water beneath its frozen exterior than all of the Earth’s oceans combined.

Future interplanetary missions from the Earth will work to study this strange environment so far away. Perhaps in the not too distant future, we may discover that our parks are not alone with life in the lakes!

To learn more about these two amazing planets, check out this blog!

Featured constellations

In August’s featured constellations, we discussed Sagittarius, Capricornus, and Delphinus.

There is a water theme in September’s edition.

Diagram of September constellations.

We discuss Pegasus the flying horse (moose or baseball diamond), Aquarius the water bearer, and Piscis Austrinus the southern fish.

Did you know…

…the speeds of light and sound can provide us with a lot of useful information? That we can even apply when we’re camping?

Read how we can apply this knowledge to stay safe when we’re camping in our post “Understanding the speeds of light and sound.”

This completes our review of the September skies. Come back next month to learn more about our galaxy and the stars of October.