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 third to fall in autumn 2021 – the Oak Moon.
Over the nights following 18 December, 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.
At the exact moment when the Moon reaches full phase, it will lie at a declination of +25°41' in the constellation Taurus , and so will appear highest in the northern hemisphere. It will be visible from all latitudes south of 54°S. Its distance from the Earth will be 405,000 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 | 05h47m30s | +25°41' | Taurus | 29'25" |
The coordinates above are given in J2000.0.
| The sky on 18 December 2021 | ||||||||||||||||||||||||||||||||||
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99% 14 days old |
All times shown in EST.
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Source
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
| 18 Dec 2021 | – Full Moon |
| 26 Dec 2021 | – Moon at Last Quarter |
| 01 Jan 2022 | – The Moon at perigee |
| 02 Jan 2022 | – New Moon |
Image credit
Simulated image courtesy of Tom Ruen.