Star Trak: May 2016

Mars will have its best opposition in more than a decade in May.

The red-orange planet will rise two hours after sunset at the beginning of the month, shining highest at 2:30 a.m. EDT (6:30 a.m. Universal Time) in the constellation Scorpius. It will appear earlier each night, until by month's end it will be high in the south around midnight. When it is opposite the sun in our sky May 22, it will clear the horizon at sunset.

Bright yellow Saturn will rise about a half hour after Mars at the start of the month. It will be much dimmer than Mars because of its much greater distance from the sun. Saturn's rings will be tilted 26 degrees to our line of sight during May. Its largest moon, Titan, will be visible in any telescope. Titan will be due north of the planet May 5 and 21 and due south May 13 and 29.

All month Saturn will form a triangle with Mars and the similarly bright red-orange star Antares (which means "rival of Mars"). You can watch the shape of the triangle change from night to night as Mars and Saturn gradually separate, while Saturn and Antares remain the same distance from each other.

As evening twilight fades in early May, Jupiter will be the only planet visible in the darkening sky. It will come into view at its highest point in the south, the best time to view it with a telescope. It will set around 4 a.m. May 1 and two hours earlier by month's end.

Mercury will pass between the sun and Earth on May 9, its first such transit since 2006. During the rest of May it will be too dim and close to the horizon to see.

Venus will be out of sight in the solar glare all month.

Meteor shower

This month Earth will encounter a stream of dust left behind in space by Comet Halley, causing the Eta Aquarid meteor shower that will peak before dawn May 5. The shower will be active for a few days before and after the peak as well.

The meteors will appear to come from a point called the radiant in the constellation Aquarius, which will rise in the east about two hours before the start of morning twilight. The higher this point is above the horizon, the more meteors will be visible. The moon will be new that night, so moonlight will not interfere.

Observers in the Northern Hemisphere may see up to 20 meteors per hour under good viewing conditions, because Aquarius will be close to the eastern horizon. Those watching in the Southern Hemisphere will see Aquarius much higher in the sky, and there may be twice as many meteors per hour at the peak.

Moon phases

The moon will be new on May 6, at first quarter on May 13, full on May 21 and at third quarter on May 29.