hiker looks at starry winter sky

Eyes on the skies – March

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.

March is one of the most glorious months to be camping, or even just spend time outdoors enjoying our parks.

On March 20, the earth passes through Spring Equinox. This is the day that formally marks the beginning of spring, and affords equal hours of sunlight and darkness.

Here are our astronomical highlights for March:

The sun

Sunrise

The sun reaches the Spring Equinox on March 20. Equinox can mean “equal” and “night”. Therefore this is a time when we have equal amounts of day and night.

The earth’s many motions combine wonderfully to provide us with fascinating observations. We rotate along our axis, of which north is currently pointed towards Polaris, the North Star. We orbit around the sun in 365 and ¼ days, and the sun orbits around the center of our galaxy in just under 250 million years.

For the purposes of discussing the position of the sun in March and the Spring Equinox, let’s just focus on two of these motions: the rotation and orbit of the earth.

Diagram showing seasonal rotation of earth around sun

The diagram above shows the earth’s motion around the sun, as well as its rotation around its axis. Even though the earth moves continuously around the sun, the direction the axis points does not change, at least not over the course of a few years.

For observers in the northern hemisphere, we see the axis of the earth pointed towards Polaris the North Star. Light from the sun (represented by the orange arrows in the diagram above) hits the earth, and results in warming the whole planet. There is more focused heating in the area directly under the sun’s rays.

During the summer, because the northern hemisphere is pointed towards the sun at noon, there is more daylight hours and more direct heat for those in the north. In the winter, the situation is reversed, as the sun’s direct light is more focused on the southern hemisphere at noon, leaving the north with less light and less heat.

During the spring and fall equinoxes, the earth is positioned such that the sun’s direct light is over the equator, right in between the northern and southern hemispheres. During this time, we have equal amount of light and darkness, and moderate temperatures. The equinoxes are important markers of seasonal change.

Here are our sunset and sunrise times for March:

March 1 March 15 March 31
Sunrise 6:53 7:29 EDT* 7:00 EDT*
Midday 12:30 13:26 EDT* 13:22 EDT*
Sunset 18:07 19:25 EDT* 19:44 EDT*

*We begin daylight savings time on the morning of Sunday, March 8.

The moon and the planets

The moon and a star

Venus continues to move further away from the sun and increase in brightness until it reaches peak brightness on March 24 (magnitude 4.4).

Venus is so bright that it can be easily seen during the daytime, as long as your eyes are shielded from the blinding light of the sun.

Diagram of the sky
Zoomed up image of Saturn, Jupiter, Mars and the moon all make a close approach on the morning of March 18, 2020. Sky chart images Courtesy of SkySafari 6 Pro

March’s lunar phases are as follows:

Moon phases

 

March constellations

Constellation diagram

In last month’s blog, we discussed Gemini the Twins, as well as two other prominent constellations seen in the winter.

This month’s post will focus on three constellations that mark the transition from winter to spring: Leo the Lion, Cancer the Crab, and Coma Berenices.

Meteor showers

March is generally a quiet month for meteor observing. Our next good meteor shower is the Lyrids, which peak in late April.

March’s night sky phenomena

The importance of having dark sky preserves cannot be understated.

In addition to the many benefits already described previously in our blog, you can see many things that others can’t from the light-polluted skies of our urban and, increasingly, our rural locations.

Gegenschein
Photo: ESO/Y. Beletsky – ESO CC BY 4.0

The zodiacal light and the gegenschein are two phenomena known for centuries, but only visible in dark skies with a good western or eastern horizon.

This completes our review of March skies

Remember to bundle up and enjoy the view from our parks. The stars await those who make the effort to enjoy them!