Signpost of summer

Happy cross-quarter day! Today marks the halfway point between spring equinox and summer solstice. In the Celtic tradition, this particular cross-quarter day was called Beltane. It marked the start of summer. Let us hope the run-up to the solstice in December rewards us with clear nights. Today is also special for the Griffin whanau. It marks the birthday of our daughter Merope. Born in Northern Ireland, she was named for one of the stars in the Pleiades, which are high in the Irish southern sky at midnight. Here in New Zealand, the Pleiades are known as Matariki, which can be seen low in the northern sky this time of year.

With the nights getting shorter, stargazers in this part of the world have to wait until after 10pm for the sky to get suitably dark. The moon reaches the last quarter phase on Monday. It won’t rise until after 3am, which means the early part of the night is darkest and prime time for stargazing. Luckily there’s lots to see.

When the sun sets, Jupiter and Saturn are easily visible in the western sky. Jupiter is by far the brighter of the two planets, looking like a bright yellow-white star. Both planets are in the constellation of Sagittarius. They are presently separated by less than five degrees, standing roughly thirty degrees above the horizon at 10pm. Despite appearing close in the sky, this is just a line of sight effect; with a distance of more than 1.5billion kilometres from Earth, Saturn is almost twice as far away as Jupiter. Over the next few weeks, these gas giants are going to get closer and closer together in the sky; a few nights before Christmas, they will be separated by less than a tenth of a degree.

Try to spot the inverted teapot of Sagittarius which is to Jupiter’s left. Further to the left, the sting of Scorpius is low the southwest. Try to catch a glimpse of Antares before it sets just after 11pm.

 - Ian Griffin