Conjunction between the Moon and Saturn

2018 Sep 17

Dominic Ford – originally published on

The Moon and Saturn will make a close approach, passing within 2°03' of each other.

From London (click to change), the pair will be difficult to observe as they will appear no higher than 15° above the horizon. They will become visible at around 19:31 (BST) as the dusk sky fades, 15° above your southern horizon. They will then sink towards the horizon, setting 4 hours and 12 minutes after the Sun at 23:21.

At the moment of closest approach, the Moon will be at mag -11.9, and Saturn at mag 1.0, both in the constellation Sagittarius.

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

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

Object Right Ascension Declination Constellation Magnitude Angular Size
The Moon 18h10m50s -20°40' Sagittarius -11.9 29'44"0
Saturn 18h10m20s -22°44' Sagittarius 1.0 16"8

The coordinates above are given in J2000.0. The pair will be at an angular separation of 98° from the Sun, which is in Virgo at this time of year.

The details of this observing event were provided courtesy of