SkyEye

The Calendar

Mars and Saturn come close together on 2 April in the constellation of Sagittarius. April also sees in the Lyrid meteor shower. With little interference from moonlight, this is an excellent year to observe these meteors.

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 Pisces → Aries

Mercury Pisces → Cetus → Pisces

Mercury is at inferior conjunction on the first day of the month, passing from the evening to the morning sky. It is best viewed in the southern hemisphere where it rises high in the east before sunrise. Northern observers, however, have a poor view of this elusive planet this month. Mercury reaches a stationary point on 14 April, going from retrograde to direct motion, and attains greatest elongation west on the penultimate day of the month.

Venus Aries → Taurus

As seen from the northern hemisphere, the evening star is rising rapidly above the western horizon.

Earth and Moon

The First Quarter Moon will be setting around the time that the radiant of the Lyrid meteor shower rises on 22 April so moonlight should not be a problem in the early morning hours. Theory suggests maximum activity will occur around 18:00 UT. Two days later, the waxing gibbous Moon is more of an issue for the π Puppid meteor shower but the radiant is still aloft after midnight when the skies will be darker. Theoretical maximum is at 00:00 UT.

The path of the Moon across the sky occasionally takes it in front of a first-magnitude star. This month it happens twice. Aldebaran is eclipsed on 19 April. Five days later, another such occultation occurs when the Moon obscures Regulus in the constellation of Leo. This is the last in a series of 19 occultations which began in December 2016. The next Regulus series won't begin until July 2025.

Mars Sagittarius

The red planet meets the ringed planet on the second day of the month when Mars and Saturn come within 1.3° of each other. Both objects lie south of the celestial equator, making this naked-eye spectacle easier to observe from equatorial and southern latitudes.

Jupiter Libra

Like the two other bright superior planets, Jupiter is easier to see the farther south you are on Earth. It rises before midnight but is best observed in the early morning hours.

Saturn Sagittarius

The ringed planet now rises before midnight for all terrestrial observers. It is found near Mars on 2 April and has nearly as close of an encounter with the Moon five days later. A once-in-thirty-years event happens on 17 April, when Saturn reaches aphelion, the point in its orbit when it's farthest from the Sun. The following day, Saturn reverses direction in the sky, going into retrograde.

Uranus Pisces → Aries

At solar conjunction on the eighteenth day of the month, Uranus is unobservable throughout April.

Neptune Aquarius

A small telescope is necessary to view the most distant planet in the solar system. It may be far enough removed from the solar glare to be visible in the early morning hours so look for it on 12 April when the waning crescent Moon passes close by.