SkyEye

The Calendar

June belongs to Jupiter. At opposition on 10 June, it is at its biggest and brightest, and thoroughly dominates the sprawling constellation of Ophiuchus.

The Solar System

The word planet is derived from the Greek word for 'wanderer'. Unlike the background stars, planets seem to move around the sky, keeping mostly to a narrow track called the ecliptic, the path of the Sun across the stars. Dwarf planets and small solar-system bodies, including comets, are not so constrained, often moving far above or below the ecliptic.

Sun Taurus → Gemini

Mercury Taurus → Gemini → Cancer

This evening apparition of Mercury is reasonably good for all planet watchers on Earth. Mercury and Mars are only 0.2° apart in the west after sunset on 18 June, just five days before greatest elongation east (a respectable 25.2°).

Venus Aries → Taurus

The southern hemisphere is no longer the favoured viewing spot for the morning star as Venus continues its descent toward the eastern horizon and its date with the Sun in mid-August. A telescopic view reveals a small, nearly full gibbous object, shining at magnitude −3.9.

Earth and Moon

The Arietids on 8 June are primarily a daytime shower but the radiant does rise just before the Sun so it may be possible to observe some of these 'shooting stars' before the sky gets light. The waxing crescent Moon does not interfere. Likewise, the waning crescent Moon does not get in the way of watching the June Boötid meteor shower near the end of the month.

Earth reaches solstice on 21 June. The word solstice means 'sun stands still' so that on this day, the solar declination reaches an extreme. In this case, the Sun appears directly over the Tropic of Cancer in the northern hemisphere. From now until the solstice in December, days will be getting longer in the southern hemisphere and shorter in the north.

Mars Gemini → Cancer

The waxing crescent Moon calls on the red planet on 5 June when the two objects appear three Moon-widths apart. Mars has a far closer encounter with Mercury on 18 June when Mercury passes just 0.2° north of Mars

Jupiter Ophiuchus

Jupiter reaches opposition on 10 June, shining brightly at magnitude −2.6. Although visible much of the night, the best views of the planet are in the tropics and southern hemisphere. For observers in northern latitudes, Jupiter remains low to the horizon. Six days after opposition, Jupiter appears 2° south of the waxing gibbous Moon.

Saturn Sagittarius

With opposition in July, Saturn brightens from magnitude +0.3 to +0.1 this month. Southern hemisphere observers have much the best views of this planet as it now rises early in the evening. Viewers in northern temperate regions continue to be frustrated with Saturn rising late and remaining low to the horizon. The waning gibbous Moon once again occults Saturn. This event occurs on 19 June from around 01:30 UT.

Uranus Aries

Uranus is best observed from southern latitudes where it is high enough above the eastern horizon before sunrise to be visible.

Neptune Aquarius

A small telescope is necessary to view the most distant planet in the solar system amongst the background stars. Neptune attains west quadrature on 9 June and later, on 22 June, begins retrograde motion. It never rises very high above the horizon when viewed from northern temperate latitudes but is well-placed in the morning sky for observers in the southern hemisphere.