How to see the planets in the night sky throughout May 2020

What planets will be in the night sky this month, and how you can spot them.

Follow the course of brilliant Venus over the month of May, as it evolves from being visible in the evening for 1.5 hours to just 30 minutes. Credit: Pete Lawrence
Follow the course of brilliant Venus over the month of May, as it evolves from being visible in the evening for 1.5 hours to just 30 minutes. Credit: Pete Lawrence

We are now entering an important and beautiful time for the planet Venus. As it swings around the part of its orbit closest to Earth, its appearance both in the sky and through the eyepiece will change rapidly.

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Inferior conjunction – when the planet appears to line up with the Sun as it transitions from the evening sky to the morning sky – occurs on 3 June.

If you’ve become used to the sight of this blazing world over in the west after sunset, this is all about to change.

At the start of May, Venus appears to shine at mag. –4.4, sets almost four hours after the Sun and through the eyepiece presents a 39 arcsecond disc, a beautiful crescent 24% illuminated.

However, the light evenings only allow 1.5 hours of viewing against a truly dark sky on 1 May.

By the end of the month Venus will appear to shine at mag. –3.7 and set just 30 minutes after sunset.

Through a telescope it will appear almost one arcminute across but a delicate, slender crescent less than 1% illuminated on 31 May.

The transition from its appearance on 1 May through to 31 May will be fascinating to watch. The crescent phases of Venus are a sight to behold and quite beautiful.

However, there is also a hint of sadness at the departure of this spectacular planet from our evening skies after so long.

Venus has a close meeting with its inner Solar System neighbour on the evenings of 21 and 22 May, mag. -0.5 Mercury appearing approximately 1.3 degrees from brighter Venus on these dates.

A slender waxing crescent Moon joins the scene on 23 May (1% lit) and 24 May (4% lit).

The phase and relative sizes of the planets for May 2020. Each planet is shown with south at the top, to show its orientation through a telescope. Credit: Pete Lawrence
The phase and relative sizes of the planets for May 2020. Each planet is shown with south at the top, to show its orientation through a telescope. Credit: Pete Lawrence

This month’s planets at a glance

Venus

  • Best time to see 1 May, approximately 30 minutes after sunset
  • Altitude 27˚
  • Location Taurus
  • Direction Southeast
  • Features Phase, subtle markings
  • Recommended equipment 75mm or larger

Mercury

  • Best time to see 22 May, 50 minutes after sunset
  • Altitude 
  • Location Taurus
  • Direction Northwest

Mercury reaches superior conjunction on 4 May, after which it re-emerges into the evening sky. And it does this in spectacular fashion, being well placed after sunset and appearing bright.

On 9 May it shines at mag. –1.7 and sets 40 minutes after the Sun. This should make it easy to see, but if you’re in doubt about whether you have, it appears close to Venus on the 21st and 22nd and this can be used as a guide.

Mercury appears at mag. –0.6 on 21 May and is separated from mag. –4.1 Venus by 1.4˚ in the evening twilight. On 22 May, mag. –0.5 Mercury is 1.3˚ from Venus.

The best strategy is to attempt to locate Venus after sunset. It’s so bright, it’s normally simple to pick it up as soon as the Sun has gone below the horizon or even with the Sun up if the sky’s clear.

Mercury continues to dim over May, but its position remains favourable. A telescopic view on 9 May reveals a tiny disc 5 arcseconds across and almost fully lit at 97% illumination.

On 22 May, when it has a close encounter with Venus, it appears 6 arcseconds across and 67% lit in a scope. By May’s end, it appears 7 arcseconds across and 45% lit.

On the 23rd a 1%-illuminated waxing crescent Moon sits 6.3˚ to the south of Venus and Mercury. The Moon sets just less than an hour after the Sun and will be a tough spot in the evening twilight.

A better opportunity occurs on the next evening when the now 4%-lit waxing crescent Moon lies 5˚
to the southeast of mag. –0.3 Mercury. From the UK this places the Moon to its left.

Mars

  • Best time to see 31 May 03:00-03:30 BST (02:00-02:30 UT)
  • Altitude
  • Location Aquarius
  • Direction East-southeast

Mars is brightening and telescopically its apparent size is increasing. However, it’s still a challenge because its apparent motion against the stars and location in the sky is hindering views. This will change as we move towards opposition in October but for now, Mars remains low in the morning sky.

On 31 May, it shines at mag. +0.0, a brightness increase of 1.4x over its appearance on the 1st. Through the eyepiece, Mars is 9 arcseconds across and appears 84% illuminated on 31 May. A waning crescent Moon lies 3.3˚ to its south on 15 May.

Jupiter

  • Best time to see 31 May from 02:00 BST (01:00 UT)
  • Altitude 10˚
  • Location Sagittarius
  • Direction Southeast

Jupiter is a bright morning planet which appears close to dimmer Saturn. On 1 May it shines at mag. –2.2, brightening to –2.4 by May’s end. A 73%-lit waning gibbous Moon lies near on the morning of 12 May.

Saturn

  • Best time to see 31 May, from 02:00 BST (01:00 UT)
  • Altitude
  • Location Capricornus
  • Direction Southeast

Saturn is a morning object, outshone by Jupiter to the west. The Moon appears nearby on the mornings of 12 and 13 May. It brightens slightly from +0.8 to +0.7 over the month.

Uranus

Uranus is not visible this month.

Neptune

Neptune is not visible this month.

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Pete Lawrence is an experienced astronomer and a co-host of The Sky at Night. This article originally appeared in the May 2020 issue of BBC Sky at Night Magazine.