The moon begins the month with some close pairings: Mars on the first; Spica and Saturn on the third; then full phase on the fifth. That full moon is the largest of the year, the time when our satellite reaches perigee (closest approach) with Earth. On the 15th, the asteroid Pallas is less than a degree from the moon; an occultation in the South Pacific. On May 22, Venus is within a fist-width away to the east; a tough observation, though, with the moon just a two-day-old sliver.
On the 20th, our moon gets in the sun's face, causing an eclipse, which will be visible in the U.S. southwest. This is an annular eclipse, meaning the moon doesn't completely cover the sun, which is interesting, since the largest full moon in 2012 just occurred. What it means is that Earth is closer to the sun than average, so the sun appears comparatively large. But the moon has travelled halfway around its orbit, so is further away than average, appearing smaller than average.
Venus is gradually losing its prominence in the western sky, closing in on its upcoming transit across the face of the sun in early June. Mark your calendars for this one, as it will be a once-in-a-lifetime event for anyone alive today. The next transit of Venus occurs in December 2117. Watch for my next column, where the transit is covered in more detail.
Mars rises in mid-afternoon, becoming visible in the south after sunset. The red planet continues eastward motion through Leo, getting further and further away from us. A close by star helps discover Mars - Regulus is the brightest star in Leo, and Mars appears just to the east of it. Silently drifting through space is the newest rover, Curiosity, due to touch down on Mars in August. More on this in a later column.
Jupiter is on the far side of the sun, in conjunction.
Saturn, still hovering near the bright star Spica in Virgo, the maiden, rises in the east in evening twilight and crosses the sky all night. The ringed planet sets near 5 a.m. Watch for the nearly full moon by Spica and Saturn May 3. If you have the opportunity to view Saturn through a telescope, make sure you take advantage, because nothing is better than seeing it in real time - photos don't do it justice.
Uranus is in the eastern morning sky in Pisces, the fish, part of the "watery" constellations.
Neptune, also in the eastern morning sky, is in Aquarius, the water bearer, wading knee-deep in the "water."
James Edgar has had an interest in the night sky all his life. He joined The Royal Astronomical Society of Canada in 2000 and quickly became involved in the society. He is editor's assistant and a contributor to the renowned Observer's Handbook, production manager of the bi-monthly RASC Journal, and is the society's national secretary.
