Eyes on the skies — August, 2017

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. Take this opportunity to enjoy the latest edition of the blog while under the beautiful stars visible from our parks.

Here are our astronomical highlights for August 2017:

The 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.

In August, we see a big change in the amount of daylight. While the sun sets around 8:45 pm at the beginning of the month, by month’s end it sets almost an hour earlier at 7:55 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 traveling by 7:00 pm.

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

Total solar eclipse

One of the most interesting phenomena in the sky occurs on August 21: a total solar eclipse.

There are two types of eclipses. If the Earth blocks out the sun’s light and casts a shadow on the moon, we have a lunar eclipse. On the other hand, a solar eclipse is if the moon blocks out the sun’s light and the moon’s shadow falls upon the Earth.

If the moon blocks out all of the sun’s light, we have the amazing and rare total solar eclipse.

Below is a map from NASA that shows the path of totality as the moon’s shadow moves across the Earth.

Map showing path of eclipseIn Ontario, we will not see totality. However if using proper eye protection, we can see a chunk of the sun being taken out by the moon, similar to the below photo of a partial solar eclipse.

Partial solar eclipse

Remember never to look at the sun without proper eye protection!

If you do witness the total solar eclipse, prepare yourself for a strange sight. The sky will become dark, the birds will start to chirp as if it was sunrise, the temperature will drop, and the brighter stars and planets will become visible.

This amazing experience is significant among many cultures. It is believed that the Haudenosaunee confederacy was marked by a solar eclipse at either August 22, 1142, or later in the middle of the 1400s to 1500s. This is because it is mentioned that the Seneca Nation, the last of the original five nations to join the Haudenosaunee, signed the Great Law of Peace after a total solar eclipse.

The moon

Pink moon in the sky with line of trees below.

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

  • Waxing gibbous on August 4
  • Full moon on August 7
  • Waning gibbous on August 11
  • Last quarter on August 15
  • Waning crescent on August 18
  • New moon on August 21
  • Waxing crescent on August 26
  • First quarter (2nd) on August 29

Moon phases

The lunar calendar on a turtle’s back

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

Depending on how we measure a lunar month, the moon goes around the Earth in approximately 28 days. This means that in one year (365 days), the moon goes around 13 times, giving us 13 lunar months with 28 days each.

Conveniently, if we examine a turtle’s shell, we find the same pattern of numbers of lunar months in a year and days in a lunar month:

For more information on the turtle shell lunar calendar, please refer to such sources as:

In the Sudbury area and want to learn more about astronomical teachings? Stop by Science North and catch the planetarium show Under the Same Stars: Minwaadiziwin.

The planets

There are two planets prominently on display this summer. Jupiter, discussed in our May edition, is well up in the constellation of Virgo (near Spica) at sunset.

Saturn can be found low in the south near the border of Ophiuchus, Scorpius and Sagittarius around midnight. To learn more about Saturn, check out our July edition.

Both planets move slowly around the sun. Jupiter takes a leisurely 12 years to go around the sun once, whereas Saturn takes almost 30 years for a complete orbit. As a result, we see less movement by these distant gas giant worlds.

For the mathematically inclined, it was discovered long ago that there is a relationship between the time it takes planets to orbit the sun and their relative distances. The squares of their times is approximately equal to the cubes of their distances. This relationship was discovered by Johannes Kepler and published in 1619, almost exactly 400 years ago!

Featured constellations: an Archer, Dolphin and a Goat

In last month’s edition of Eyes on the Skies, we discussed the Summer Triangle, Scorpius, and Scutum.

This month, we ‘ll discuss Sagittarius, Capricornus, and Delphinus. To make things easier, we left last month’s constellations on this month’s sky chart for reference.

Sky chart for August

Delphinus the Dolphin

Delphinus is one of those constellations that really resembles what it is supposed to be. It’s easy to see the outline of a dolphin breaching over the top of an ocean.

There are two stories that speak of Delphinus. In one, the dolphin is sent as a messenger by Poseidon to court his future wife.

In another story, Delphinus is the real life rescuer of Arion, who was thrown overboard by shipmates who wished to steal his money. A final song on his lute lured a group of dolphins, one of which rescued Arion from the sea.

Chart of Delphius.

Delphinus has a beautiful double star, Gamma Delphini, which marks out the nose of the dolphin. A small telescope reveals two coloured stars in orbit around one another.

Double star.

Capricornus the Goat Fish

Unlike the aptly named Delphinus the Dolphin, Capricornus does not look like a goat or a fish.

However, the origins of this constellation are among the oldest of any known, going back to ancient Sumerian and Babylonian times.

In Greek times, this constellation was associated with Pan, god of the countryside. He could instill “Pan”-ic with his loud calls.

Sagittarius the Archer (or the teapot/coffee pot)

Sagittarius is meant to be an archer riding his horse. This is not to be confused with a centaur, which is a half horse and half man, also often associated with a bow and arrows.

However, from our northern latitudes, it is hard to see the horse part of this constellation, as it is usually low by the treeline. As a result, most northern residents see a teapot or coffee pot as shown in our diagram.

When we look towards Sagittarius, we are looking towards the center of our galaxy. In fact, the very center is just off and upwards from the spout of the teapot.

Astronomers have observed much evidence to support a super massive black hole at the center, which they refer to as Sagittarius A. This black hole has the mass of over 4 million suns!

But don’t worry; we are far enough away that it has little effect on us.

Because we are looking inwards towards the centre of our Milky Way Galaxy (more on this in next month’s edition), we see many interesting objects in this direction. M8, the Lagoon Nebula, and M20, the Trifid Nebula, are but two of the many interesting objects that can be seen with a large pair of binoculars or a telescope.

The Lagoon Nebula is an emission nebula. This is an interstellar cloud of gas that is lit up from the ultraviolet light of stars, which is then transformed into visible light from charged hydrogen.

The Trifid Nebula, meaning three lobes, is part emission nebula, part reflection nebula (coming from visible starlight that is reflected but not transformed), and part dark nebula (light is obscured by dust).

Off towards the left (east) of the top star of the teapot is M22, a globular star cluster. This cluster contains hundreds of thousands of stars, and is one of the brightest you can see in the night sky.

There are many interesting and beautiful objects that await observing in this area of the sky.

Want to spend some time observing the skies?

Our parks have a wide variety of Astronomy Nights and Star Parties this month.

As well. the Killarney Provincial Park Observatory is now available for families and individuals to sign out free of charge.

This completes our review of the August skies…

Come back next month to learn about our galaxy and the stars of September.