See Mercury return to the evening sky in April 2022

By Pete Lawrence

Published: Monday, 28 March 2022 at 12:00 am

In April 2022 the Solar System’s smallest planet Mercury reaches a favourable evening elongation, setting over two hours after the Sun.

Mercury reaches superior conjunction on 2 April when it appears to line up with the Sun on the far side of its orbit. Consequently, Mercury won’t be visible at the start of April.

""
Credit: Pete Lawrence

But its re-emergence into the evening sky throughout the res of the month is pretty spectacular, the planet appearing bright and distancing itself from the Sun rapidly.

On 8 April, Mercury shines at mag. –1.6 and sets 35 minutes after sunset.

By 12 April, just four days later, the planet will be setting a full 60 minutes after the Sun, having dimmed a bit to mag. –1.3 by that date.

This pattern continues over the following days, Mercury reaching greatest eastern elongation on 29 April when it will be separated from the Sun by a respectable 20.6˚.

""
As April 2022 progresses, Mercury becomes an evening object, visible after sunset. Credit: Pete Lawrence

On 29 April, Mercury shines at mag. +0.4 and sets 135 minutes after the Sun.

On this date, Mercury sits 1.3˚ south of the Pleiades open cluster. for a beautiful conjunction worthy of photographing.

The Solar System’s innermost planet, Mercury, never appears to wander very far from the Sun in the sky. As a consequence, it appears in the evening or morning twilight rather than against a truly dark sky.

If you have a good flat west-northwest to northwest horizon, this will give the best view of Mercury with the Pleiades.

""
Mercury appears 1.3˚ south of the Pleiades on 29 April 2022. Credit: Pete Lawrence

As the pair lose altitude the sky will appear darker, but this is countered by the thicker layer of atmosphere we have to look through close to the horizon, causing both objects to appear dimmer.

A view of Mercury at the end of April through the eyepiece of a telescope will reveal it as a tiny crescent.

With an apparent diameter of 8 arcseconds on the evening of 30 April, Mercury will appear 33%-lit.

Observing the planets in April 2022

""
The phase and relative sizes of the planets in April 2022. Each planet is shown with south at the top, to show its orientation through a telescope. Credit: Pete Lawrence

Mercury

  • Best time to see: 29 April, 30 minutes after sunset
  • Altitude: 13˚
  • Location: Taurus
  • Direction: West-northwest
  • Features: Phase, surface markings through larger instruments
  • Recommended equipment: 75mm, or larger

Venus

  • Best time to see: 30 April, 30 minutes before sunrise
  • Altitude: 5˚ (low)
  • Location: Pisces
  • Direction: East

Venus is a morning planet but doesn’t rise to a good altitude. At April’s start, mag. –4.2 Venus rises 80 minutes before the Sun. By the month’s end, now at mag. –4.0, it rises an hour before sunrise. Appearing near mag. +1.1 Mars and mag. +0.9 Saturn at the month’s start, Venus appears close to mag. –2.0 Jupiter at the end of the month.

If you have a flat east-southeast horizon, on 27 April it might be possible to catch Venus and Jupiter separated by 3.4˚ with a waning crescent Moon located 4.3˚ below Venus. On 30 April, Jupiter and Venus appear separated by 41 arcminutes, a figure that drops to 22 arcminutes on 1 May.

Mars

  • Best time to see: 30 April, 04:00 UT
  • Altitude: 6˚ (low)
  • Location: Aquarius
  • Direction: East-southeast

Mag. +1.0 Mars and +0.9 Saturn converge at the start of April to lie just 19 arcminutes apart on 5 April. Unfortunately, despite rising some 80 minutes before the Sun on this date, their altitude pre-sunrise remains low as seen from the UK.

Fortunately, mag. –4.2 Venus will be on hand to guide the way, Venus appearing 7.3˚ to the left of the fainter pairing as seen from the UK on 5 April.

Jupiter

  • Best time to see: 30 April, 30 minutes before sunrise
  • Altitude: 5˚ (low)
  • Location: Pisces
  • Direction: East

Jupiter is poorly positioned in the morning sky at April’s start, rising 20 minutes before the Sun on 1 April. By the month’s end, its position improves and the mag. –1.9 planet appears above the eastern horizon, an hour before sunrise.

Saturn

  • Best time to see: 30 April, 04:00 UT
  • Altitude: 9˚ (low)
  • Location: Capricornus
  • Direction: Southeast

Saturn is a poorly positioned morning planet. On 4 and 5 April, Mars appears close to Saturn, a flat southeast horizon being needed to see this meeting. On 5 April, both planets appear separated by 19 arcminutes, Saturn shining at mag. +0.9 and Mars at +1.0, so well matched. Bright Venus appears 7.3˚ left of the pair as seen from the UK.

A waning crescent Moon sits near to Saturn on the mornings of 24 and 25 April. By the month’s end, Saturn remains at mag. +0.9 and despite rising two hours before the Sun, remains low in the dawn twilight.

Uranus

  • Best time to see: 1 April, 20:40 UT
  • Altitude: 8˚ (low)
  • Location: Aries
  • Direction: West

Uranus slips from view, becoming harder to make out against dark skies at a meaningful altitude. Given a flat west-northwest horizon, a slender 6%-lit waxing crescent Moon appears to sit 1.3˚ from Uranus on 3 April, the altitude of the pair is low as darkness falls, around 6˚.

Neptune

Neptune is a morning planet, but not observable this month.

This guide originally appeared in the April 2022 issue of BBC Sky at Night Magazine.