When can you see the 'supermoon' this week?
PUBLISHED: 19:00 18 March 2019
Spring equinox falls on Thursday, with a full supermoon making an appearance...our columnist reveals more about the phenomenon.
It is spring, and the equinox on March 20 is about as special as a heavenly event can be.
For not only is the date when day equals night (more or less) it is also a full moon... and a supermoon at that (Werewolves take note).
We think of equinox as being 12 hours of day and 12 of night but like so many blithely accepted norms, it is a little more complicated than that.
According to earthsky.org the March 2019 equinox takes place at 21.58pm - two minutes to 10pm in the evening.
From then, the days will be longer than the nights until the autumn equinox, in September, reverses that. Some of the mysteries of our galaxy unfold in an equinox. For instance, according to an article by Bruce McClure, the sun rises and sets more quickly around the equinoxes.
Why does it happen? Well for those of a mathematical bent, here’s the brief explanation. At an equinox the sun rises due east and sets due west, meaning the setting sun hits the horizon at its steepest possible angle.
The supermoon will arrive just under four hours after the equinox, at 1.43am. I know what you’re thinking - haven’t we already had supermoons? Yes, there have been two already this year but this one is the final supermoon of the year. The March full moon is known in some parts as a “full worm” moon - because the ground is now soft enough for wormcasts to appear - elsewhere it is a “full sap” moon.
The last time the moon and the equinox came together so neatly was in March 2000 and it won’t happen again until March 2030!
I may stay up for the equinox at 9.58pm but I won’t bother waiting for the supermoon - even though the forecast for only partial cloud cover overnight makes seeing it a possibility.
Oh, and it may be a little soon to pack away the winter vests.