Galaxy photo by Hubble telescope

Eyes on the skies — October, 2017

Welcome to the Ontario Parks “Eyes on the Skies” series. This 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.

October is a month of transition as the last few warm days depart and we prepare ourselves for winter.

However, cold weather does not mean we should abandon the great outdoors. On the contrary, the peace and serenity found at this time of the year make the trip to any park all the more enjoyable.

Here are our astronomical highlights for October 2017:

The sun

The sun

With the sun having passed the fall equinox, we now experience more hours of darkness than light.

Additionally, because we are still using daylight savings time, our sunrise, midday, and sunset times are all one hour forward.

Here are the sunrise and sunset times for October:

October 1 October 15 October 31
Sunrise 7:24 am 7:43 am 8:05 am
Midday 1:15 pm 1:11 pm 1:09 pm
Sunset 7:05 am 6:39 pm 6:12 pm

The moon

The moon

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

  • Waxing gibbous on October 2
  • Full moon on October 5
  • Waning gibbous on October 8
  • Last quarter on October 11
  • Waning crescent on October 15
  • New moon on October 19
  • Waxing crescent on October 24
  • First quarter on October 28

Moon phases

The planets

After an amazing several months of viewing the largest planets of our solar system Jupiter and Saturn, October skies brings an end to their view. This is because Jupiter has already set by sunset, and Saturn sets in the early twilight hours.

However, in the early morning skies before dawn the brilliant planet Venus is joined by the red planet Mars. A relatively rare close approach occurs on the morning of October 5 (image below at left).

If you have a clear view of the eastern sky at sunrise, you will witness Venus standing just a scant half-moon width to the upper left of the planet Mars. As seen through a pair of binoculars or a wide field telescope, the view will resemble the image at lower right.

Planets
Images courtesy of SkySafari 5 Pro.

Featured constellations: A fish, a ram and a triangle

In last month’s edition we discussed Pegasus, Aquarius and the southern fish – Piscis Austrinus.

This time we will discuss the more popular northern fish (Pisces), Aries the Ram, and Triangulum the Triangle.

Map showing all of the month's constellations.

Pisces the Fish

Pisces constellation

Pisces the Fish is one of the ancient constellations.

In the Greek story a massive sea monster – Typhon – was sent to destroy the Gods. After being alerted to the monster’s presence, Aphrodite and Eros swam into the Euphrates River.

Depending on the version of the story, either they were rescued by two fish, or changed themselves into two fish. Pisces represents these two fish.

The most right (western) of the two fish is not too difficult to see underneath the great square of Pegasus. However, the most left (eastern) of the two fish is made up of fairly faint stars.

This constellation is a good test of one’s vision in the dark skies of our provincial parks!

Triangulum the Triangle

Triangle constellation

Any pattern of stars forms an asterism. Constellations are the asterisms that have become accepted by the International Astronomical Union.

Triangulum is perhaps the simplest of all the constellations because of its composition of a three-star asterism. It is often depicted as a triangle ruler, but there is some question as to whether it should represent a triangle or the Greek letter delta.

Within the constellation of Triangulum is one of the most beautiful galaxies easily visible in the night sky. Known as the Pinwheel Galaxy, the Triangulum Galaxy, or M33, this galaxy is a classic example of a spiral galaxy.

The galaxy is quite large and as a result has a low surface brightness. This means its brightness is spread out over a large area making it difficult to see.

Ironically, while it may be visible in binoculars or by the unaided eye in dark skies, it is very difficult to see in most small telescopes.

Galaxy photo by Hubble telescope

In this NASA Hubble Space Telescope photo (above), the spiral arms are easy to make out as well as the H2 areas (red blobs along the arms).

These regions host massive star formations amidst interstellar clouds, and indicate that M33 is a younger galaxy.

M33 is a slightly closer neighbor than its more famous big brother – M31, the Andromeda galaxy (to be discussed in next month’s edition). Our galaxy along with M33, M31, and about 20 other galaxies, all form what we call the Local Group of galaxies, a loose galactic cluster.

Aries the Ram

Aries constellation

The last of our constellations for October is Aries the Ram. In many ancient cultures the ram played special importance as an animal which was sacrificed.

In this particular case, Aries the Ram is the animal from which the Golden Fleece of Greek mythology originates. The Golden Fleece was sought after by Jason in his voyage with the Argonauts. After being sent down by the Gods on a mercy mission Aries shed its fleece, therefore it is only a faint constellation. The Golden Fleece itself would make Jason king if only he could obtain it, and so began his quest.

Aries has important significance in astronomy as the ancient astronomer – Hipparchus – noted the path of the sun in the sky crosses Aries on the first day of the spring equinox. Therefore it was named the “First Point of Aries.”

However the Earth, like a child’s toy top, slowly wobbles. This wobble is known as precision, and it takes approximately 26,000 years to complete one wobble.

Since the time of the ancient Greeks, the first point of Aries has shifted one twelfth of a complete circle. Therefore, it is no nowhere near to Aries during the spring equinox.

October Meteor Showers

Two meteor showers peak in October. The Draconids (which originate from the constellation of Draco the Dragon) peak on the night of October 7. They usually display less than ten meteors per hour in dark skies.

The Orionid meteor shower, with dust originating from comet Halley, is set to peak on the night of October 20. Viewers in dark skies should see as much as 20 meteors per hour. The best time to look is after 1:00 am, at which point the view of the night sky is starting to face in the same direction as the Earth’s travel around the Sun.

For a detailed explanation of meteor showers, check out this link.

This completes our review of the October skies…

Come back next month to learn about the greatest epic of constellations in the sky – the story of Perseus and Andromeda.

Want to learn more about the celestial history of Halloween? Click here.