The Moon's monthly orbit around the Earth will carry it to its furthest point from the Sun – its aphelion – at a distance of 1.0060 AU from the Sun.
This happens at around the time when the Moon's orbit carries it around the far side of the Earth as seen from the Sun, at around the same time that it passes full moon.
At the moment of the Moon's aphelion, the Earth will lie at a distance of 1.0038 AU from the Sun, and the Moon will lie at a distance of 1.0060 AU from the Sun.
This distance between the Earth and Moon will be 0.0027 AU (402,000 km).
The positions of the Sun and Moon in the sky will be:
| Object | Right Ascension | Declination | Constellation | Angular Size |
| The Moon | 21h47m30s | 15°08'S | Capricornus | 29'38" |
| Sun (centre) | 11h55m | 0°30'N | Virgo | 31'51" |
The coordinates above are given in J2000.0.
The sky on 21 Sep 2018
| The sky on 21 September 2018 | ||||||||||||||||||||||||||||||||||
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93% 12 days old |
All times shown in EDT.
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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
| 16 Sep 2018 | – Moon at First Quarter |
| 24 Sep 2018 | – Full Moon |
| 02 Oct 2018 | – Moon at Last Quarter |
| 08 Oct 2018 | – New Moon |
Image credit
Simulated image courtesy of Tom Ruen.