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If planet-watching is your thing, you’ll be a little challenged to spot them this month. Venus and Jupiter are easy to see, actually, but you’ll have to make the effort to be up well before dawn, by 6 a.m. or so in most places. Venus will be unmistakable, gleaming brightly low in the southeast. Jupiter isn’t nearly so bright, but it’s high up, more than halfway to overhead, when dawn arrives.
Pivoting into the evening sky, you have a tiny chance of spotting Mars very low in the west-southwest about 30 minutes after sunset. Your odds improve a bit for seeing Mercury in that same location late in October.
So that once again leaves us with Saturn, now well up in the southeast at nightfall, for the evening’s planetary entertainment. You can use it as a celestial benchmark for exploring this part of the evening sky.
Sky & Telescope
Look above Saturn, by two or three fists, for a very large box of four stars that are roughly the same medium brightness. This simple pattern is known the world over as the Great Square of Pegasus, and it forms the body of this famous mythical horse. But this horse is weird! It’s flying upside down (as seen from the Northern Hemisphere), and it has no hindquarters.
The star at the left corner of the box, the brightest of the four, is called Alpheratz [al-FEE-rats], an Arabic name meaning “navel of the horse.” For many centuries this star was considered to be part of both Pegasus and the adjacent constellation Andromeda, which extends to the left. But Alpheratz is no longer part of Pegasus, at least officially. In 1930, astronomers assigned it exclusively to Andromeda, and in fact it’s now Andromeda’s brightest star.
The sky to the left of Alpheratz holds a wonderful celestial treasure: the Andromeda Galaxy, comparable in size and mass to our own Milky Way, and a whopping 2½ million light-years away. When you gaze at it, you’re looking at the most distant object that can be seen with the human eye. But getting to its exact location is a little tricky — and fortunately, this month’s Sky Tour podcast tells you exactly where to look!
This months episode also tells you how to look for bits of Halley’s Comet flashing in the night, and it offers from tips for how treat the Halloween goblins in your neighborhood to some easy stargazing. So download Sky Tour now!
