Cool Lights on Summer Nightstesttest
The nascent crescent moon emerges from the glow of sunset low in the west-northwest Thursday evening. Above the moon is Mercury with the Gemini twins Pollux and Castor higher still. Sunset Friday finds the waxing crescent a little higher in the west with Mercury, Pollux, and Castor farther to its right.
Mercury outshines all but the brightest stars and even Mars and Saturn. Even so, Mercury is the least familiar of the naked-eye planets, as it is so close to the sun it never climbs too high above our horizon. This week you’ll find the innermost planet 30 to 45 minutes after sunset. Scan the west-northwest horizon as soon as it darkens, looking for a strong light piercing twilight’s haze. Binoculars will help, as will dimmer Castor and Pollux loosely aligned above Mercury.
Sunset reveals Mars high in the southwest midway between the constellations Leo and Virgo. Twenty degrees to the west of Mars is Regulus, the lion’s heart, while to the other side of the red planet are the bright lights of Saturn and Spica. Monday evening the moon is just a few degrees to the right of the red planet until the two set around midnight.
Saturn is high in the south at dusk and is joined by equally bright Spica just five degrees lower. Wednesday the first-quarter moon joins the picture, forming a tight triangle until setting around 1am.
Venus and Jupiter rise in the northeast ahead of the sun. Jupiter is the higher of the two, with six degrees between them, but Venus is more than twice as bright than Old Jove. The two present a fine pair, visible for less than an hour before dawn for the next few weeks.
As if on cue, the stars of the Summer Triangle shine in the east at sunset. Brightest and highest is Vega in the constellation Lyra, with Deneb in Cygnus to the north and Altair in Aquila to the south.