Autumn Equinox - a bit on the dark side

Shine on the September Harvest Moon

The autumn equinox falls on the 16th September this year. This is when the days and nights are of equal length. The seasons close the door on summer and open up to the autumnal months ahead when the days become colder and darker.

The moon is also eclipsed, but not fully. You are unlikely to see it from the UK. It is neither “total” nor “partial” but “prenumbral”.

A prenumbral eclipse occurs where the Moon’s distance from the Earth is too great to line up completely for a total eclipse effect. The edges of the Sun are visible throughout the event.

The full moon that falls closest to the autumn equinox is known as the “Harvest Moon”. Although they seem to harvest earlier these days, it used to be around this time when the final harvests of crops were made. In the times before electricity, the light of full moon meant that work could continue into the night….depending on the weather!

Full moons are given names. Whilst they vary country by country, they represent what the locals reckon the weather might be in the ensuing month.

For example, July saw the “Thunder Moon”. We had no thunder here but it must have been somewhere!

It is not an exact science!

What is a blue moon?

Commonly meaning a rare event, the traditional definition is:

The third of four full moons in a season. 

This occurs approximately every 2.7 years.

However, more recently a “blue Moon” is identified as:

The second full moon in a calendar month.

As there are 13 full moons (and new Moons) in a year, this is going to happen at least yearly.

Shown as simply a circle, most diaries and calendars show the days when the Moon is full. 

Many also show the days when the Moon is new which is noted as a dark circle. …but you cannot see it on that day unless it is fully eclipsing the Sun. Cloud dependant, you can normally spot the sliver of the new Moon a day or two after new moon when the evening Sun will not be so bright as to obscure it.

This sliver,  the bit that is illuminated forms the crescent. The remainder is in shadow so you cannot see it unless Earthshine lights it up!

What is Earthshine?

Earthshine is the light “bounced “off the Earth from the Sun.

Alternatively

Moonshine – illicit liquor distilled in America

Earthshine – illicit liquor distilled in the dark side of the Moon.

Cheers!