Conjunction between the Moon and Saturn

2017 Aug 3

Dominic Ford – originally published on

The Moon and Saturn will make a close approach, passing within 3°26' of each other.

From London (click to change), the pair will be difficult to observe as they will appear no higher than 16° above the horizon. They will be visible in the evening sky. They will become visible at around 21:08 (BST) as the dusk sky fades, 16° above your southern horizon. They will then reach its highest point in the sky at 21:32, 16° above your southern horizon. They will continue to be observable until around 00:23, when they sink to 8° above your south-western horizon.

At the moment of closest approach, the Moon will be at mag -12.3, and Saturn at mag 0.9, 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 17h24m00s -18°29' Ophiuchus -12.3 29'30"0
Saturn 17h22m30s -21°54' Ophiuchus 0.9 17"7

The coordinates above are given in J2000.0. The pair will be at an angular separation of 130° from the Sun, which is in Cancer at this time of year.

The details of this observing event were provided courtesy of