Jupiter will reach opposition on 26 September 2022 and, when viewed through the eyepiece, appears brightest and largest for this period of observation.

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Reaching an impressive mag. –2.8, it slips from Cetus into Pisces throughout September, the planet located east of the faint but distinctive Circlet asterism.

As the nights are getting longer and darker, now's a great time to point your telescope or binoculars at the gas giant and see if you can observe Jupiter's moons.

For more stargazing advice every week, listen to our Star Diary podcast or sign up to receive the BBC Sky at Night Magazine e-newsletter.

Jupiter Opposition 2021 Prabhu, Mleiha, UAE, 19 August 2021 Equipment: ZWO ASI462MC camera, Celestron 11-inch EdgeHD Schmidt-Cassegrain
Jupiter Opposition 2021 by Prabhu, Mleiha, UAE, 19 August 2021. Equipment: ZWO ASI462MC camera, Celestron 11-inch EdgeHD Schmidt-Cassegrain

A bright full Moon lies near to Jupiter on the nights of 10 and 11 September, an impressive sight if you have clear skies.

As they rise above the eastern horizon early evening on 11 September, Jupiter and the Moon will appear a little over 3˚ apart.

On opposition night, it sits 4˚ east of the First Point of Aries, one of two intersections in the sky where the celestial equator and the ecliptic cross.

The First Point of Aries marks the start of the RA coordinate system (00h00m00s).

A chart showing Jupiter's path in the night sky throughout September 2022, when it reaches opposition
A bright Jupiter sits near the Circlet and the First Point of Aries as it nears opposition. Credit: Pete Lawrence

Jupiter shines at mag. –2.8 on opposition night, reaching a peak altitude of 37˚ as seen from the centre of the UK.

Jupiter rotates quickly, the planet completing one rotation in under 10 hours.

This brings atmospheric features into and out of view surprisingly quickly.

A 100mm or larger telescope will show the planet’s famous Great Red Spot, the appearance of which can be determined using the freeware WinJupos application.

Jupiter Opposition by David Burlington, Corby, UK. Equipment: SW200p Newtonian, qhy5L-11 CCD, TAL 2X Barlow, EQ6 PRO mount.
Jupiter Opposition by David Burlington, Corby, UK. Equipment: SW200p Newtonian, qhy5L-11 CCD, TAL 2X Barlow, EQ6 PRO mount.

In addition to the planet’s detailed atmosphere, a small telescope will also reveal the four largest and brightest Jovian moons, the so-called Galilean moons: Io, Europa, Ganymede and Callisto.

The inner three can appear to pass in front of and behind the planet, but Jupiter’s apparent tilt from Earth has now increased such that Callisto appears to miss the disc, although its shadow can still clip Jupiter’s southern pole.

This phenomenon can be observed on 5 September between 00:30 BST (23:30 UT on 4 September) and 01:47 BST (00:47 UT).

Find out more about Jupiter at opposition in our video below:

How to see the planets in September 2022

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

Jupiter

  • Best time to see: 26 September, 00:00 UT
  • Altitude: 37˚
  • Location: Pisces
  • Direction: South
  • Features: Detail of the planet’s atmosphere, Galilean moons
  • Recommended equipment: 75mm or larger

Mercury

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

Mercury’s position in the evening sky is poor at the start of September, appearing dim and setting shortly after sunset. Inferior conjunction is on 23 September. Mercury then reemerges into the morning sky where it becomes easier to see. By the end of the month, it shines at mag. +1.8 and rises 70 minutes before the Sun.

Venus

  • Best time to see: 1 September, 30 minutes before sunrise
  • Altitude: 7˚ (low)
  • Location: Leo
  • Direction: East-northeast

Shining at mag. –3.8 on 1 September, Venus can be seen rising above the east-northeast horizon 90 minutes before the Sun. Telescopically, it isn’t well presented, at 10 arcseconds across and nearly fully illuminated. By the end of the month, Venus’s position degrades further and it becomes harder to see, rising 40 minutes before sunrise.

Mars

  • Best time to see: 30 September, 04:50 UT
  • Altitude: 59˚
  • Location: Taurus
  • Direction: South

Mars shows dramatic changes as it approaches Mars opposition on 8 December. On 1 September, shining at mag. –0.1, it is located just north of the Hyades. Through a telescope the planet is 9 arcseconds across on 1 September, increasing to 11 arcseconds and mag. –0.6, a beacon between the horns of Taurus by the month’s end. A 58%-lit waning gibbous Moon lies 3˚ north of Mars on the morning of 17 September.

Saturn

  • Best time to see: 1 September, 23:00 UT
  • Altitude: 21˚
  • Location: Capricornus
  • Direction: South

Following opposition on 14 August, Saturn remains well placed all month, dropping in brightness only slightly from mag. +0.4 on 1 September to +0.6 by the end of the month. A bright waxing gibbous Moon sits nearby on the nights of 7/8 and 8/9 September.

Uranus

  • Best time to see: 30 September, 02:30 UT
  • Altitude: 54˚
  • Location: Aries
  • Direction: South

Morning planet Uranus is perfectly placed for UK observation, able to reach an altitude of around 50˚ under dark skies. Visible as a green-hued mag. +5.7 disc through the eyepiece, a rare lunar occultation of Uranus takes place on the evening of 14 September.

Neptune

  • Best time to see: 16 September, 00:15 UT
  • Altitude: 34º
  • Location: Aquarius
  • Direction: South

Neptune reaches opposition on 16 September, but at its great distance from Earth this usually favourable position has very little effect on the planet’s visual appearance. Able to reach an altitude around 30˚ under dark sky conditions all month long, you’ll need at least binoculars to spot mag. +7.8 Neptune.

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

Authors

Pete Lawrence, astronomer and BBC The Sky at Night presenter.
Pete LawrenceAstronomer and presenter

Pete Lawrence is an experienced astronomer and astrophotographer, and a presenter on BBC's The Sky at Night.

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