The moon begins the month as a slight sliver in the west at sundown. Jupiter is just a few degrees to the right.
By June 7, Mars and Spica bracket the moon - one above and the other below left. Toward month end, Venus shares the eastern morning sky with our satellite. Full moon is June 13.
Mercury has just passed its highest point in the sky as June opens, presenting a great chance to view the elusive planet. Be quick, though, as it speeds in front of the sun and is lost in the glare by June 13.
Venus, the Morning Star, rises in the east about an hour before dawn. This isn't a particularly good time to view the planet, as the angle of the ecliptic keeps it close to the horizon before being overpowered by the sun's bright light.
Mars is just past its closest apparition and best viewing opportunity, as Earth slowly draws away from the Red Planet. On the evening of June 7, the waxing gibbous moon will hover below Mars through the night, with the bright Spica off to the east. Spica, a bright double star in Virgo, the Maiden, has been a Mars companion now for months. It's no longer idle speculation that Mars once had surface water, creating sedimentary layers, river channels and water-driven chemistry. The Mars rovers, Spirit, Opportunity and Curiosity have amassed ample evidence of a watery past, but that was likely billions of years ago. There is no free water there now, as the low atmospheric pressure causes whatever may briefly appear to quickly boil away.
Jupiter, the giant gas planet, is in the western sky at sundown near the Gemini twins. This is a great time to observe Jupiter's Galilean moons as they seemingly dance around their parent planet. The moons are Io, Europa, Ganymede and Callisto. The first three are in a 1:2:4 resonance, meaning that for every orbit of Ganymede, Io goes around four times, and Europa goes around twice. Binoculars will easily show any of the moons that are visible, and a telescope shows them even better. Because they are further away from us, the moons appear as tiny specks. In fact, only Europa is smaller than our moon. For those who follow such events, a double shadow transit precedes a rare triple shadow transit on June 3 - a real challenge, since the events occur in full daylight.
Saturn, the Ringed Planet, is a beautiful sight in a telescope, so be sure to take any opportunity to view it. Little else can stir the imagination like the sight of the golden-hued planet against the velvety black backdrop of deep space. On the evening of June 9, the moon passes below Saturn, an occultation in the Southern Hemisphere.
Uranus, like Neptune below, has a very short viewing time, rising about 3 a.m. in the east.
Neptune rises in the east about 2 a.m. and has a very short window of opportunity, as the sun rises shortly afterward. Both Neptune and Uranus cross the sky during daylight.
- James Edgar has had an interest in the night sky all his life. He joined the Royal Astronomical Society of Canada in 2000 and is now assistant editor and a contributor to the Observer's Handbook, production manager of the bi-monthly RASC Journal and the society's national secretary. He was given the RASC Service Award at the 2012 General Assembly in Edmonton.
