Throughout the month, Jupiter shines brightly. On 1 June it will be mag. –2.4, increasing to –2.6 by the month’s end as it approaches opposition in July. An 87%-lit waning gibbous Moon lies near to Jupiter and Saturn on 9 June.
Jupiter is the largest planet in the Solar System, and an example of an object known as a gas giant. When you look at it through a telescope, you’re looking at the top of the planet’s extensive atmosphere. Here you can see all sorts of atmospheric phenomena.
Spinning once on its axis in just shy of 10 hours, the planet bulges at its equator, appearing oblate even through a small instrument.
What to look for when you observe Jupiter
Jupiter’s most obvious features, visually speaking, are the two dark bands that encircle the planet to the north and south of the equator. These are known as the north equatorial belt (NEB) and south equatorial belt (SEB).
The southern edge of the SEB has a scalloped-out feature in which sits the most famous long-term storm in the entire Solar System, Jupiter’s Great Red Spot. The scalloped-out feature is known as the Red Spot Hollow.
All of these features are just about visible in a 100mm scope at around the 100x magnification mark, increased aperture increases visibility greatly.
Small scopes are also good at revealing Jupiter’s four largest moons, the so-called Galilean moons, Io, Europa, Ganymede and Callisto.
Jupiter is currently rather low as seen from the UK and this renders fine detail difficult to see due to atmospheric instability.
Saturn and Jupiter are currently quite close ahead of a ‘Great Conjunction’ which is due to take place at the end of 2020.
How to see the planets this month
- Best time to see 30 June, 02:00 BST (01:00 UT)
- Altitude 15°
- Location Sagittarius
- Direction South
- Features Belts, Great Red Spot, atmospheric disturbances, Galilean moons
- Recommended equipment 150mm or larger
- Best time to see 1 June, 40 minutes after sunset
- Altitude 9.5° (low)
- Location Gemini
- Direction West-northwest
Mercury is an evening object, technically for the whole of June. Unfortunately, unlike last month’s spectacular evening appearance, its brightness drops fast along with its post sunset altitude, meaning it’s likely to be lost from view from mid-month onwards.
Greatest eastern elongation occurs on 4 June when it will appear separated from the Sun by 23.6°.
- Best time to see 30 June, 1 hour before sunrise
- Altitude 5°
- Location Taurus
- Direction East-northeast
Venus reaches inferior conjunction on 3 June, when it lines up with the Sun and cannot be seen. Sometimes we can view Venus as it passes through inferior conjunction, but some are better than others as the apparent distance from the Sun varies from one conjunction to the next.
Here, the apparent separation is too small to be safe, Venus passing within half a degree of the Sun’s centre on 3 June.
Venus returns to the morning sky after inferior conjunction, rising 1.5 hours before the Sun by 30 June. Although its position will not be as favourable as it was in the evening sky it will appear bright at mag. –4.3 at June’s close.
A special event occurs on the morning of 19 June when Venus will be occulted by the waning crescent Moon. At the time Venus will be showing a 7% crescent and appear 51 arcseconds across.
Read our guide to find out how to observe and photograph the lunar occultation of Venus.
The Moon will show a 3% crescent at this time. The occultation takes place from 07:37 UT and reappearance starts at 08:43 UT.
- Best time to see 30 June from 03:00 BST (02:00 UT)
- Altitude 17°
- Location Pisces
- Direction East-southeast
Mars is now improving despite its apparent eastward travel against the stars keeping it tucked into the dawn twilight. On 1 June a scope will show mag. +0.0 Mars to have a 9 arcsecond disc with a phase of 84%. At the month’s close it will have increased to mag. –0.5.
- Best time to see 30 June, from 02:00 BST (01:00 UT)
- Altitude 16.5°
- Location Capricornus
- Direction South
Saturn appears just east of Jupiter, low above the southern horizon in the early hours. The off-white planet appears to brighten from mag. +0.7 to +0.5 during June. An 87%-lit waning gibbous Moon is nearby on the morning of the 9 June.
Uranus is a morning planet that’s now too entrenched in the dawn twilight for serious viewing.
- Best time to see 13 June, from 02:00 BST (01:00 UT)
- Altitude 5° (very low)
- Location Aquarius
- Direction East-southeast
Low in the east-southeast as dawn twilight begins to brighten. Mars is nearby on 13 June and mornings near this date. At mag. +7.9 Neptune is lost in dawn’s twilight. A last quarter Moon sits below Mars and Neptune on the 13th.
Pete Lawrence is an experienced astronomer and a co-host of The Sky at Night. This article originally appeared in the June 2020 issue of BBC Sky at Night Magazine.