SkyEye

The Calendar

An amazing annular solar eclipse takes place on 10 June. Earth is at a solstice on 21 June and Mars passes just south of Praesepe two days later.

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

Mercury vanishes from the west early in the month and undergoes inferior conjunction on 11 June, the day after aphelion. It emerges in the east at dawn before the end of the month in what is a decent morning apparition for southern hemisphere observers. Second-magnitude Mercury passes 1.8° north of first-magnitude star Aldebaran on 22 June and ends retrograde motion the following day.

Venus Taurus → Gemini → Cancer

The evening star appears 1.5° south of the waxing crescent Moon on 12 June, the same day on which the planet reaches perihelion. Venus is best seen from the southern hemisphere where it continues to gain altitude above the western horizon.

Earth and Moon

A ring of fire is seen on 10 June when the New Moon moves between Earth and the Sun, resulting in an annular solar eclipse. 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.

Mars Gemini → Cancer

Mars is less than 3° south of the waxing crescent Moon on 13 June. Ten days later it has a far closer encounter with M44, also known as Praesepe or the Beehive Cluster, when it passes only 0.3° south of the centre of that open star cluster. Mars is getting increasingly difficult to see from northern latitudes as it sinks deeper into the evening twilight but skies are still dark in the southern hemisphere when the red planet finally sets in the early evening hours.

Jupiter Aquarius

Jupiter reaches its most northerly declination of the year on 16 June and enters into retrograde motion five days later. Observers in southern latitudes are best placed to view the giant planet which rises during the evening. It is only now that northern planet watchers might see Jupiter rise before midnight but it never gains much altitude before the sky brightens in the morning.

Saturn Capricornus

Saturn rises in the early evening hours for astronomers situated in the southern hemisphere, allowing the planet plenty of time to gain significant altitude before midnight. The gas giant is finally an evening sky object for observers in northern temperate latitudes too, although it is best seen after midnight. Saturn is getting closer to Earth and the rings are opening slightly, resulting in the planet brightening from magnitude +0.6 to +0.4 over the course of the month.

Uranus Aries

Uranus is visible in the east before dawn. It is most easily viewed from the southern hemisphere where it gains considerable altitude before the sky brightens. The waning crescent Moon pays a visit on 7 June, passing 2.1° south of the planet.

Neptune Aquarius

A small telescope is necessary to view the most distant planet in the solar system and the best place to put that telescope is the southern hemisphere where Neptune rises during the mid- and late evening hours. The faint planet arrives at west quadrature on 13 June and reaches its farthest point north (in terms of declination) for 2021 nine days later. Neptune spends nearly half of the year in retrograde motion and this year it begins on 26 June.