The Moon and Neptune will make a close approach, passing within a mere 27.0 arcminutes of each other. From some parts of the world, the Moon will pass in front of Neptune, creating a lunar occultation. The Moon will be 24 days old.
From Cambridge however, the pair will not be observable – they will reach their highest point in the sky during daytime and will be no higher than 16° above the horizon at dawn.
The Moon will be at mag -11.6; and Neptune will be at mag 7.9. Both objects will lie in the constellation Aquarius.
They will be close enough to fit within the field of view of a telescope, but will also be visible through a pair of binoculars.
A graph of the angular separation between the Moon and Neptune around the time of closest approach is available here.
The positions of the pair at the moment of closest approach will be as follows:
| Object | Right Ascension | Declination | Constellation | Magnitude | Angular Size |
| The Moon | 23h02m10s | 7°36'S | Aquarius | -11.6 | 31'16"2 |
| Neptune | 23h01m40s | 7°10'S | Aquarius | 7.9 | 2"2 |
The coordinates above are given in J2000.0. The pair will be at an angular separation of 75° from the Sun, which is in Taurus at this time of year.
The sky on 20 May 2017
| The sky on 20 May 2017 | ||||||||||||||||||||||||||||||||||
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32% 24 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
| 19 Nov 2016 | – Neptune ends retrograde motion |
| 16 Jun 2017 | – Neptune enters retrograde motion |
| 05 Sep 2017 | – Neptune at opposition |
| 22 Nov 2017 | – Neptune ends retrograde motion |
Image credit
The Moon in conjunction with Venus and Jupiter, with the Very Large Telescope in the foreground. Image © Y. Beletsky, ESO, 2009.