Conjunction between the Moon and Neptune

2017 Aug 10

Dominic Ford – originally published on

The Moon and Neptune will make a close approach, passing within 0°49' of each other.

From London (click to change), the pair will be visible in the morning sky. They will become accessible at around 22:13, when they rise 7° above your eastern horizon. They will then reach its highest point in the sky at 02:45, 31° above your southern horizon. They will be lost to dawn twilight at around 05:11, 23° above your south-western horizon.

At the moment of closest approach, the Moon will be at mag -12.5, and Neptune at mag 7.8, both in the constellation Aquarius.

The pair will be a little too widely separated to fit comfortably within the field of view of a telescope, but will be visible to the naked eye or a through pair of binoculars.

The precise positions of the Moon and Neptune at the moment of closest approach will be as follows:

Object Right Ascension Declination Constellation Magnitude Angular Size
The Moon 23h00m50s -08°12' Aquarius -12.5 30'50"1
Neptune 22h59m50s -07°25' Aquarius 7.8 2"3

The coordinates above are given in J2000.0. The pair will be at an angular separation of 154° from the Sun, which is in Cancer at this time of year.

The details of this observing event were provided courtesy of