The Moon and Mars will make a close approach, passing within 4°43' of each other. The Moon will be 11 days old.
From Cambridge , the pair will be visible in the evening sky, becoming accessible around 19:02 (EST), 17° above your south-eastern horizon, as dusk fades to darkness. They will then reach their highest point in the sky at 21:06, 23° above your southern horizon. They will continue to be observable until around 00:34, when they sink below 7° above your south-western horizon.
The Moon will be at mag -12.3; and Mars will be at mag -1.6. Both objects will lie in the constellation Capricornus.
They 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.
At around the same time, the pair will also share the same right ascension – called a conjunction.
A graph of the angular separation between the Moon and Mars 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 | 20h18m30s | 19°26'S | Capricornus | -12.3 | 29'30"0 |
| Mars | 20h21m20s | 24°07'S | Capricornus | -1.6 | 17"5 |
The coordinates above are given in J2000.0. The pair will be at an angular separation of 125° from the Sun, which is in Virgo at this time of year.
The sky on 20 Sep 2018
| The sky on 20 September 2018 | ||||||||||||||||||||||||||||||||||
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82% 11 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
| 27 Aug 2018 | – Mars ends retrograde motion |
| 23 Aug 2020 | – Mars 2020: a great chance to see the red planet |
| 09 Sep 2020 | – Mars enters retrograde motion |
| 06 Oct 2020 | – Mars at perigee |
Image credit
The Moon in conjunction with Venus and Jupiter, with the Very Large Telescope in the foreground. Image © Y. Beletsky, ESO, 2009.