Night fallen on a campsite with an illuminated tent and small burning fire

Eyes on the skies — August

Welcome to the Ontario Parks “Eyes on the Skies” series. This space (<– see what we did there?) will cover a wide range of astronomy topics with a focus on what can be seen from the pristine skies found in our provincial parks.

August is here at last with its fine weather, fewer mosquitos, and longer nights. All of the constellations and objects from July are still visible, but there are a few exciting new things to see this month.

Here are our astronomical highlights for August 2019:

The sun

The sun continues its apparent drop in elevation as it approaches next month’s fall equinox (equal light and dark).

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.

sunset

In August, we see a big change in the amount of daylight. The sun sets around 8:55 pm at the beginning of the month, but by month’s end, it sets almost an hour earlier at 8:06 pm.

Because of the canopy of trees surrounding most campsites, the horizon will be blocked, meaning you will lose the sun about an hour earlier. If you’re travelling around August 31, make sure you finish your hike or paddle by 7:00 pm.

This can shorten our recreation time, but from an astronomy perspective, we gain almost two more hours of darkness to appreciate the night skies.

Sunrise and sunset times

August 1 August 15 August 31
Sunrise 6:07 am 6:25 am 6:44 am
Midday 1:32 pm 1:30 pm 1:26 pm
Sunset 8:55 pm 8:35 pm 8:06 pm

The moon

The moon has long captivated observers of all ages. August lunar phases of the moon occur as follows:

  • new moon on August 1
  • waxing crescent on August 5
  • first quarter on August 7
  • waxing gibbous on August 12
  • full moon on August 15
  • waning gibbous on August 19
  • last quarter on August 23
  • waning crescent on August 26

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

Jupiter rises well before sunrise and sets around 1:00 am (at mid-month). It is a spectacular sight at any magnification. Even low power binoculars are more than powerful enough to show its four largest “Galilean” moons. Click here to learn more about Jupiter.

Saturn, further to the east and a little fainter (as compared to Jupiter), rises just before sunset and sets at around 3:00 am (at mid-month). Saturn requires only the smallest of telescopes to see the rings. Click here to learn more about Saturn.

Observing the moons of the Jovian planets

Whereas the terrestrial (Earth-like) planets have none to few moons, the Jovian (Jupiter-like) Gas Giant planets all have many moons (see table below) with data from NASA’s excellent website on solar system exploration as of August, 2019.

Planet Name Moons
Terrestrial (Earth-Like) Mercury 0
Venus 0
Earth 1
Mars 2
Jovian (Jupiter-like) Gas Giants Jupiter 79
Saturn 62
Uranus 27
Neptune 14
Dwarf Planet Pluto 5

With binoculars on Jupiter, one can easily see the dance of the largest moons discovered by Galileo in the early 1600s. Because Jupiter rotates rapidly (in under 10 hours), the change in the moons’ position is easily noticeable in hours!

You can use online tools, such as Sky & Telescopes “Jupiter Moon” page to find the position for any night.

Sky chart images courtesy of SkySafari 6 Pro showing Jupiter and it's moons.
Sky chart images courtesy of SkySafari 6 Pro

Saturn’s moons appear fainter than Jupiter’s primarily because Saturn is almost twice the distance aware of the sun. However, in a large telescope, such as available to the public for free at the Killarney Provincial Park Observatory, you can see many of Saturn’s moons.

Sky chart images courtesy of SkySafari 6 Pro

Meteor showers

August brings one of the most enjoyable meteor showers of the year – the Perseids.

A meteor shower occurs when the earth enters the debris field of a comet that has long ago passed around the sun. These bits of dust and grit, often no bigger than your thumbnail, enter the earth’s atmosphere and burn up high above the ground (see our post on meteor showers for more information).

meteors

This year, the Perseid meteor showers occur on a full moon which will render many of the fainter ones invisible. If you want to see them, the best time would be after 3:00 am on the morning of August 13.

Featured constellations: an archer, dolphin and a goat

In this month’s featured constellations, we discuss Sagittarius, Capricornus, and Delphinus.

Sky chart for August

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