Conjunction between the Moon and Saturn

2017 Oct 24

Dominic Ford – originally published on

The Moon and Saturn will make a close approach, passing within 3°14' of each other.

From London (click to change), the pair will be difficult to observe as they will appear no higher than 12° above the horizon. They will become visible at around 18:09 (BST) as the dusk sky fades, 12° above your south-western horizon. They will then sink towards the horizon, setting 2 hours and 34 minutes after the Sun at 20:20.

At the moment of closest approach, the Moon will be at mag -10.8, and Saturn at mag 1.2, both in the constellation Ophiuchus.

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 17h34m00s -19°03' Ophiuchus -10.8 29'29"5
Saturn 17h32m40s -22°16' Ophiuchus 1.2 15"6

The coordinates above are given in J2000.0. The pair will be at an angular separation of 52° from the Sun, which is in Virgo at this time of year.

The details of this observing event were provided courtesy of