Mercury and M44 will make a close approach, passing within a mere 22.6 arcminutes of each other.
From Cambridge however, the pair will not be observable – they will reach their highest point in the sky during daytime and will be no higher than 0° above the horizon at dusk.
Mercury will be at mag 0.0; and M44 will be at mag 3.1. Both objects will lie in the constellation Cancer.
They will be close enough to fit within the field of view of a telescope, but will also be visible to the naked eye or through a pair of binoculars.
A graph of the angular separation between Mercury and M44 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 |
| Mercury | 08h39m40s | 19°19'N | Cancer | 0.0 | 6"9 |
| M44 | 08h40m20s | 19°40'N | Cancer | 3.1 | 0"0 |
The coordinates above are given in J2000.0. The pair will be at an angular separation of 25° from the Sun, which is in Gemini at this time of year.
The sky on 4 Jul 2018
| The sky on 4 July 2018 | ||||||||||||||||||||||||||||||||||
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62% 21 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.
Image credit
The Moon in conjunction with Venus and Jupiter, with the Very Large Telescope in the foreground. Image © Y. Beletsky, ESO, 2009.