SkyEye

The Calendar

The Moon is conspicuous by its absence this month, reaching 'new' phase twice. Unfortunately, it is near full during the annual Perseid meteor shower and floods the sky with light.

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 Cancer → Leo

Mercury Gem → Cancer → Leo

This dawn apparition of Mercury slightly favours northern latitudes over the south. The closest planet to the Sun attains greatest elongation west on 9 August and then begins to lose height above the eastern horizon. Mercury appears 1.2° south of the open cluster Praesepe on 17 August and reaches perihelion three days later. Look for Mercury in the east before the end of the month when it vanishes in morning twilight.

Venus Cancer → Leo

Venus reaches perihelion on 8 August, the point in its orbit where it's closest to the Sun. However, this event will not be visible from Earth as Venus will be at superior conjunction only a few days later on 14 August. The morning star is no more, with the evening star appearing next month.

Earth and Moon

The nearly full Moon spoils this year's appearance of the famous Perseid meteor shower on 13 August. Two New Moons grace this month, however, with the second one sometimes called a 'Black Moon'. Think of it as the New Moon equivalent of a Blue Moon (which occurs when the Moon is full).

Mars Leo

Mars reaches aphelion, the point in its orbit when it's farthest from the Sun, on 26 August. However, it is lost to view in the west before then as it vanishes in the glare of the Sun.

Jupiter Ophiuchus

The largest planet in the solar system returns to direct motion on 11 August. It is a bright, magnitude −2.3 object in the large and unremarkable constellation of Ophiuchus. It sets by midnight when viewed from northern temperate latitudes but remains aloft a little longer for southern hemisphere planet watchers.

Saturn Sagittarius

Now past opposition, Saturn is an evening sky object, not setting until morning twilight. It is best viewed from equatorial and southern latitudes where it is high in the sky. The ringed planet is eclipsed by the waxing gibbous Moon on 12 August in an occultation event beginning around 07:30 UT.

Uranus Aries

Uranus returns to retrograde motion on 12 August. Now rising before midnight, it is subtly brightening as it approaches opposition in October.

Neptune Aquarius

A small telescope is necessary to view the most distant planet in the solar system but it is brightening slightly as it heads to opposition next month. It now rises before midnight.