The Sky Tonight
Moon at perigee (nearest to Earth) - May 6th noon WST. New Moon - May 7th 5pm WST. First Quarter - May 14th 1am WST. Moon at apogee (furthest from Earth) - May 19th 6am WST. Full Moon - May 22nd 5am WST. Last Quarter - May 29th 8pm WST.
Mercury will be lost in the evening twilight as it heads toward inferior conjunction and a transit across the face of the Sun on the 10th. This transit, the first since 2006, will not be visible over Australia. The next, in 2019, also escapes Australian observers, however the subsequent transits will be visible but you will have to wait till 2032 and 2039. Following inferior conjunction the planet climbs into the eastern morning dawn to begin a favourable observing window from late May through to mid-June.
Venus is too close to the Sun for observation this month and will be in superior conjunction (Venus and Earth on opposites sides of the sun) early in June. The planet returns as the Evening Star in the mid-July twilight sky.
Mars will be in focus of planetary observers during May and June with its favourable opposition on the 22nd of this month. Its closest approach to Earth occurs on the 31st at a distance of 75,279,145 km.
Jupiter is visible in the early north-eastern evening sky in Leo. On the 10th, the gas giant appears stationary as it comes to the end of its four month retrograde loop as the Earth overtakes it - thereafter the planet moves from west to east across the sky. On the 15th, the 9 day old waxing gibbous Moon appears close to the planet.
Saturn, rising around the end of astronomical twilight, is visible below Mars and Antares. With the planet's impending opposition early next month, it's time to devote some telescope time to this ringed jewel of the Solar System. The Saturnian moons are fun to track down and identify, the brightest and largest Titan, can be seen in binoculars.
Uranus returns to the pre-dawn eastern sky in Pisces after its solar conjunction last month.
Neptune, in Aquarius, is only visible in the morning eastern sky, rising around 1am mid-month.
DWARF & MINOR PLANETS, COMETS
Pluto, in Sagittarius, rises around 8.30pm mid-month in the eastern evening sky. Retrograde motion brings the dwarf back toward the 3rd magnitude star Pi Sagittarii in preparation for a very close encounter next month.
Comet C/2013 8X1 (PANSTARRS) opens May in Pisces rising more than two hours before dawn begins. By the end of the first week PANSTARRS moves into Aquarius where it remains for the remainder of the month. Towards the end of May the comet will be rising before midnight and should brighten from 10th to 9th magnitude.
The eta-Aquarids are linked with Halley's Comet and rank as one of the most popular of the Southern Hemisphere showers. They are visible for a few hours before dawn, from 19th April to 28th May.
[Information Source for above: "Astronomy 2016 Australia" by Glenn Dawes, Peter Northfield and Ken Wallace]
Have you ever wondered when a particular constellation will be visible? Check the culmination dates for the constellations, which are given for 21:00 local time. Also included in this list are their common and genitive names, and their officially recognized abbreviations. These dates are valid world-wide, but not all constellations will be visible from all latitudes.