Nightsky by Astronomer Dhara Patel: The March Equinox

March signifies the start of spring for many in the northern hemisphere but in the astronomical calendar, it’s marked by a particular point in time – the March equinox.

The earth orbits the sun and due to its axial tilt, the Sun shines directly over the earth’s northern hemisphere in the summer and over the southern hemisphere in our winter.

But at the March equinox (also known as the vernal or spring equinox in the northern hemisphere), the sun shines directly over the equator and we have nearly equal hours of daylight and darkness throughout the world on this day.

This year the vernal equinox falls on March 20 and from this point onwards, our hours of  daylight start to get longer.

Although the long, dark nights of winter are beginning to fade, following the moon this month will help locate a number of spectacles to see in the night sky.

On March 9 in the constellation of Leo, we had the full moon sitting beside the blue-white coloured star Denebola and this full moon is also a supermoon.

The moon’s elliptical orbits means that its distance from the earth changes as it orbits it.

If the moon comes within 90 per cent of its closest distance to the earth and coincides with a full moon (or new moon), it’s generally called a supermoon but there’s
actually no precise astronomical definition for this phenomenon.

In the early evening look to the south east; the moon should appear slightly larger and brighter but April’s full moon will actually be the closest supermoon of the year.

By the time the moon reaches its last quarter phase on March 16, it will be best seen in the south east in the early morning before the sun rises.

However, if you wait until the early morning of March 18, the moon will be beside the naked eye planets – Mars and Jupiter and by the following morning will sit beside Saturn – also visible without an optical aid.

These naked eye planets will look like bright stars – Jupiter’s brightness will dominate and Mars will have a reddish colour.

On these mornings, the moon will help you locate them, but you can catch this planetary display throughout the month!