I wonder how many millions of people have noticed Venus shining in the western sky at dusk? Only the moon is more obvious. It will soon return to the evening sky, but for now, darkness reigns at nightfall. Astute skywatchers have also noticed how Venus and Mars have been inching closer together over the past month. As often happens, two planets approach and then pass directly over one other in conjunction. But not this time.
Even though Mars is moving to the east (left), it’s slowly being overtaken by Earth’s orbital motion around the sun, causing it to drift slightly to the west each night. Meanwhile, Venus, which had been making great progress toward Mars, is now slowly moving back west, headed towards the sun’s direction. So the two planets get close, but not too much and won’t undergo a conjunction. Tonight, they’re separated by a little more than 5° or three fingers held together at arm’s length. They’ll be just a hair closer on Feb. 1-2 and then slowly separate for good as Venus picks up speed and moves ever more rapidly to the west.
Due north of a line connecting Mars and Venus you’ll see two fainter but still easy naked eye stars that outline the bottom of the Square of Pegasus, a familiar fall asterism that in winter lurches to the west. Now look another fist and a half above that line for the two stars that form the top of the Square. Perfect — you’ve now found the Great Square. Feel free at this point to follow the zigzag line of stars extending from the lower right corner of this stellar box to complete the figure of Pegasus the Winged Horse.
Now, focus your attention on Alpheratz, the star in the upper left of the Square. A fist and a half almost directly above and a little to the right, you’ll arrive at the Andromeda Galaxy. I’m not saying you’ll see this straight off with the naked eye, but if your sky is really dark and you play your gaze around the spot, you’ll notice a hazy patch of light. That’s it. A pair of binoculars will show the galaxy very clearly as an oval glow with a brighter center. Andromeda is the closest large galaxy to the Milky Way galaxy at 2.5 million light years away and containing an estimated 1 trillion stars!
And all you needed was Venus to get there.