Over the course of the next few nights this week two cosmic superstars will appear to glide by each other in our Earthly skies. Skywatchers are reporting already seeing comet Pan-STARRS approaching the iconic Andromeda Galaxy (M31). The two objects will appear to be at their closest on the night of April 3rd and 4th when they will only appear to be separated by no more than 2.5 degrees – equal to the width of your three middle fingers at an outstretched arm’s length.
Comet Pan-STARRS has been putting on a great show for skywatchers throughout March and now is starting to slowly fade as it heads back towards the outer solar system. However as it moves away from the Sun it is slowly rising higher in the early evening northwestern sky, making it easier for observers to catch sight of even the comet’s tail. (Related: Pictures: Comet PanSTARRS debuts in Southern Hemisphere)
This juxtaposition of Pan-STARRS and Andromeda galaxy will offer up an amazing photo opportunity for those with the right tracking and telephoto equipment. Even naked-eye observers might get a view out in cottage country – far from any hint of light pollution, but suburbanites will get an eyeful with binoculars too – placing the pair easily in the same field of view. If you have a small telescope, say with a mirror or lens at least 3 to 4 inches wide - you might get lucky enough to catch the comet’s fan-shaped tail possibly brushing over the galaxy itself!
To locate M31 and the comet look to the low (about 15 degrees altitude) northwest sky about an hour after local sunset. It’s best to use binoculars to sweep the sky to initially track them down.
What blows my mind is that these two grand celestial objects are so vastly different when it comes to scale- and their proximity in the sky is just an illusion. While the comet currently is about 200 million km away from Earth, the giant spiral galaxy sits at a whopping 2.6 million light years distant. Also amazing to consider is the difference in their actual sizes. While the comet’s nucleus is no more than a few kilometers wide, Andromeda galaxy spans more than 200,000 light years across and is filled with nearly 400 billion stars.
For a growing gallery of backyard shots of this rare astronomical conjunction check out spaceweather.com and if you want to try hunting down Pan-STARRS and M31 for yourself then visit Sky and Telescope’s observing guide.
So if you live in the Northern Hemisphere, have clear skies the next few nights (until April 8th or so) try to witness this grand comic encounter for yourself- a humbling moment for sure!