Simulated image courtesy of Tom Ruen.

Full Moon

Dominic Ford, Editor
From the Moon feed

Objects: The Moon
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The Moon will reach full phase. At this time in its monthly cycle of phases, the Moon lies almost directly opposite the Sun in the sky, placing it high above the horizon for much of the night.

The sequence of full moons through the year are often assigned names according to the seasons in which they fall. This month's will be the second to fall in autumn 2020 – the Hunter's Moon.

Over the nights following 31 October, the Moon will rise around an hour later each day, becoming prominent later in the night. Within a few days, it will only be visible in the pre-dawn and early-morning sky. By the time it reaches last quarter, a week after full moon, it will rise at around midnight and set at around noon.

This will be the second occasion when the moon reaches full phase in October 2020. It is relatively rare for two full moons to fall within the same calendar month, since they occur at 29.53-day intervals.

It happens on average once every 2.7 years, when a full moon takes place within the first few hours of a month.

In recent time, full moons such as this have commonly been called blue moons. This usage of the term is a twentieth century innovation, however, which originally stemmed from a misprint in Sky & Telescope magazine, which appeared in March 1946.

Historically, the term blue moon has been used to describe the third of four full moons to fall within one of the Earth's seasons.

In this system, the sequence of full moons through the year are assigned names according to the seasons in which they fall. Usually only three names are needed for the full moons in each season. If a fourth fell within the same season, one of them was left without a name. This additional full moon was called a blue moon.

At the exact moment when the Moon reaches full phase, it will lie at a declination of +11°01' in the constellation Aries , and so will appear highest in the northern hemisphere. It will be visible from all latitudes south of 68°S. Its distance from the Earth will be 406,000 km.

The exact position of the Moon at the time it reaches full phase will be:

Object Right Ascension Declination Constellation Angular Size
The Moon 02h28m20s +11°01' Aries 29'24"

The coordinates above are given in J2000.0.

The sky on 31 October 2020
Twilight ends
Twilight begins

15-day old moon
Waxing Gibbous


15 days old

Rise Culm. Set
Mercury 06:22 11:52 17:22
Venus 04:27 10:30 16:32
Moon 18:14 00:23 06:57
Mars 16:53 23:12 05:36
Jupiter 13:02 17:41 22:21
Saturn 13:19 18:03 22:47
All times shown in EDT.


The circumstances of this event were computed using the DE430 planetary ephemeris published by the Jet Propulsion Laboratory (JPL).

This event was automatically generated by searching the ephemeris for planetary alignments which are of interest to amateur astronomers, and the text above was generated based on an estimate of your location.

Related news

31 Oct 2020  –  Full Moon
08 Nov 2020  –  Moon at Last Quarter
14 Nov 2020  –  The Moon at perigee
15 Nov 2020  –  New Moon

Image credit

Simulated image courtesy of Tom Ruen.






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