The Moon and Mars will share the same right ascension, with the Moon passing 1°47' to the north of Mars. The Moon will be 27 days old.
At around the same time, the two objects will also make a close approach, technically called an appulse.
From Cambridge , the pair will be difficult to observe as they will appear no higher than 16° above the horizon. They will be visible in the dawn sky, rising at 04:35 (EST) – 2 hours and 22 minutes before the Sun – and reaching an altitude of 16° above the eastern horizon before fading from view as dawn breaks at around 06:09.
The Moon will be at mag -9.6, and Mars at mag 1.8, both in the constellation Virgo.
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.
A graph of the angular separation between the Moon and Mars around the time of closest approach is available here.
The positions of the two objects at the moment of conjunction will be as follows:
| Object | Right Ascension | Declination | Constellation | Magnitude | Angular Size |
| The Moon | 11h48m30s | 4°17'N | Virgo | -9.6 | 30'59"6 |
| Mars | 11h48m30s | 2°30'N | Virgo | 1.8 | 3"7 |
The coordinates above are given in J2000.0. The pair will be at an angular separation of 28° from the Sun, which is in Virgo at this time of year.
The sky on 17 Oct 2017
| The sky on 17 October 2017 | ||||||||||||||||||||||||||||||||||
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3% 27 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
| 29 Jun 2016 | – Mars ends retrograde motion |
| 26 Jun 2018 | – Mars enters retrograde motion |
| 27 Jul 2018 | – Mars at opposition |
| 31 Jul 2018 | – 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.