night sky

Eyes on the skies — July

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.

July has finally arrived. Summer is the perfect time to escape the noise, air and light pollution of the larger urban areas and head to the peace and serenity of a provincial park.

July also hosts a number of beautiful constellations, full of interesting stories to tell.

Here are our astronomical highlights for July, 2019:

The sun

The earth reaches its furthest point to the Sun on July 4, 2019. This point is called “Aphelion” and is, on average, about five million kilometres further than when the earth is at its closest point (“Perihelion”) in early January.

Sun, low and bright over a lake with a forested shoreline, reflecting in the water

As described in our March edition, the reason that our summers are hot in spite of the distance to the sun has everything to do with the tilt of the earth and not its distance.

Sunrise and sunset times

July 1 July 15 July 31
Sunrise 5:39 am 5:49 am 6:07 am
Midday 1:29 pm 1:32 pm 1:32 pm
Sunset 9:20 pm 9:13 pm 8:57 pm

The moon 

A less than half fun moon high above a forested lake with blues and pinks in a softly clouded sky

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

lunar phases

Did you know this year is the 50th anniversary of the Apollo Moon Landing?

The planets

Jupiter is well-placed throughout July and is spectacular 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 rises around twilight and, on July 9, is due south at 1:00 am.

Saturn

Saturn is one of the original wandering stars known from ancient times. Of all the ancient planets, Saturn moved the slowest (it takes 30 years to orbit the sun once) and was associated with majesty and grandeur.

When Galileo turned his “optic tube” towards the stars, he observed the rings and drew them in his journal. His views through his first telescope (in 1610) were quiet poor. However, his observations made just over 400 years ago (in 1616), were good enough to show that Saturn was different from all the other planets.

He didn’t understand what he was seeing, but we have since learned that this planet is surrounded by an immense and spectacular ring system.

Galileo sketch

Like Jupiter, Saturn is a gas giant planet of immense size (around 120,000 km across). Its rotation rate is just over 10 hours, which compared to earth’s 24 hour day is quite speedy.

Again like Jupiter, Saturn’s rotation rate and chemical composition have created cloud belts, although they are fainter and show less contrast then Jupiter’s.

As large as Saturn is, it is actually not very dense. If you placed the planet in a giant bathtub, it would probably float! However, it is in the ring system that Saturn has received its nickname as the crown jewel of the planets.

Saturn’s rings are made of ice and dust particles ranging from the size of a thumbnail to a small building. They are most likely leftover debris from the initial formation and collisions of the planets and early solar system material.

Saturn has over 62 moons and it’s believed that many of these moons help to “shepherd” the ring material into a constant orbit.

Saturn’s largest moon – Titan – is larger than Mercury and has its own atmosphere.  Titan goes through its own liquid cycle. Like the Earth, it rains on Titan!

The rain pools in rivers, ponds and lakes which then evaporate forming clouds. However, unlike the Earth, Titan’s liquid cycle is made up of Methane rather than water.

Meteor showers and satellites

There are no major meteor showers occurring during the month of July. Often observers see fireflies and, for a moment, be fooled into thinking they are seeing a meteor!

However, even though there are no major meteor showers, there are always fragments of one form or another of dust falling upon the Earth. These “sporadic” meteors can often account for as many as 10 per hour on any given night in a dark, moonless sky.

Meteor observing, especially in the dark skies of our provincial parks, is one of the most enjoyable ways to get into astronomy. You don’t need any special equipment other than your eyes. A lounge chair, sleeping bag and a buddy are all welcome additions to enjoying the spectacle. If you take a look at our constellation charts, you can practice learning your constellations while you watch for the meteors.

Featured constellations: the birds of summer

In this month’s featured constellations, we take a look at the Summer Triangle and the constellations of Lyra, Cygnus, Aquila, and Scorpius.

constellations

Learn more about these star stories here.

Did you know…

…we can see surface detail on Mars with even a small telescope? For more information about Mars, visit our post Looking up at the planet Mars.

This completes our review of the July skies…

Come back next month to learn more about our galaxy!