The moon begins the month nearly full, at the end of the first eclipse season of the year. Recall last month there was a total solar eclipse March 20. Two weeks later, on April 4, a lunar eclipse occurs, visible in the Canadian west and over the Pacific Ocean.
April 8, Saturn is two degrees south of the moon, a very early morning observation (just after midnight). April 21 sees an occultation of Aldebaran, the bright star in Taurus, The Bull. Another occultation occurs April 26 at midnight when minor planet Juno slips behind the moon.
Mercury won’t be visible for the first half of the month, but comes out of the sun’s glare in the western evening sky to join Mars and Venus at dusk. The speedy planet quickly moves up near Mars and is joined by the very new moon April 19, passes Mars April 22, and heads toward Venus. On the evening of April 30, Mercury is in among the Seven Sisters (the Pleiades), just about at the top of its orbit arc.
Venus, the bright beacon in the western evening sky, outshines Mars by several magnitudes. Besides being closer and appearing larger, Venus is shrouded by a thick mantle of clouds that reflect much of the sunlight falling on the cloud tops. Those same clouds are mostly sulphuric acid, raining down on the uninhabitable surface with surface temperatures hot enough to melt lead.
Mars is found in the western evening sky, joined by Venus, Mercury and the moon. By the middle of the month, Mars does a disappearing act behind the sun, not to show for another four months in August.
Jupiter is well placed for viewing high in the southern sky at sunset. The gas giant has been retrograding throughout the past few months, and completes that apparent westward motion April 8. The Beehive Cluster is just off to the west during this transition. The four Galilean moons of Jupiter make for a lively dance as they rapidly orbit the planet. Their positions change even during an observing session.
Saturn is also retrograding in the eastern sky just after midnight. The ringed planet is in the constellation Scorpius. Watch for a close approach of the moon with Saturn April 8.
Uranus and Neptune are almost impossible to spot, since they rise just ahead of the sun in the eastern morning sky, but the ecliptic (the path of the planets) is almost level with the horizon. So the sky brightens with dawn just as these two distant gas planets come into possible view.
