This month Neptune and Mars will appear together in the sky in an event known as a ‘conjunction’. Generally, the term ‘conjunction’ refers to the appearance of two or more celestial objects close together in the night sky.
Planetary conjunctions aren’t that uncommon and although they have little scientific interest, when bright planets are involved such as Mercury, Venus, Mars, Jupiter or Saturn, the view can be impressive.
Where the dimmer worlds of Uranus and Neptune are involved, it’s the challenge of spotting them close to their brighter neighbours that creates the pull.
If you’re interested in spotting more conjunctions, read Paul Money’s guide to the best conjunctions to see in 2020, or find out more about how to observe the planets in the night sky this month.
How to spot the Mars-Neptune conjunction
A naked-eye view of the early morning sky at around 02:00 BST from the south of England, 11 June 2020. Neptune can be found in within the area described by the red circle. Credit: Stellarium
On 13 June brightening planet Mars sits close to the dim outer planet Neptune. Mars shines at mag. –0.2 and is easy to identify because of its distinct salmon-pink colour.
Neptune is faint and will be easily lost against the bright background June morning sky, so the best strategy is to locate Mars first and use it as a stepping-stone to locate Neptune.
On 13 June, Neptune is positioned 1.7° north-northwest of Mars but the distance isn’t vastly different several days before or after this closest apparent approach.
Catching the pair early is the best way to secure Neptune and this will require you to have a flat east-southeast horizon.
Binoculars or a scope using a low power eyepiece are the best choices for grabbing the pair visually. Alternatively, a camera setup with a 400mm or shorter focal length lens should help you secure them.
If you’re struggling to locate Mars and Neptune, find out which apps will help you pinpoint objects in the night sky in our guide to stargazing with a smartphone.
And if you do manage to spot or even photograph what you see, be sure to let us know by emailing us at email@example.com or getting in touch via Facebook, Twitter and Instagram.
Pete Lawrence is an experienced astronomer and co-host of The Sky at Night. This guide originally appeared in the June 2020 issue of BBC Sky at Night Magazine.