Go See Comet Pan-STARRS While You Can!

By Phil Plait

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Posted Thursday, March 14, 2013, at 8:00 AM

A stunning portrait of comet Pan-STARRS (upper left), the thin crescent Moon (lower right), and an observatory on La Palma. Click to embiggen.
Image credit: Babak Tafreshi

The bright comet Pan-STARRS is putting on quite a show right now. It just moved into the northern skies after a splashy display for those south of the equator, and it’s still quite bright. I went out on Tuesday night and despite the clouds I could easily see it in my binoculars near the setting (and extremely thin) crescent new Moon. The next night, Wednesday Mar. 13, was a bit better. It was very fuzzy in my telescope and actually looked better through binoculars; the comet itself is so fuzzy that the telescope just magnified the blurriness. Once I knew where to look using the binocs it was pretty easy to spot with just my eyes, even though it was low and there was haze in the sky.

I mentioned this on Twitter, and my feed lit up with people posting pictures they had taken or had seen. The picture at the top of this post is my favorite; taken by my friend and astrophotographer Babak Tafreshi, it shows the Moon and the comet setting behind the William Herschel Telescope dome on La Palma in the Canary Islands. At an elevation of over 2300 meters (1.4 miles), clouds form below the observatory, so there are usually clear skies there. I’ve visited this observatory and it’s magnificent even without the celestial visitor seen here.

The comet and the setting crescent Moon.
Image credit: My friend Boo, used by permission.

You don’t need to be a professional astrophotographer to get great shots, though. My pseudonymous friend Boo took the shot above using just a camera (Canon EOS 40D) and a 250mm lens. I shrank it considerably to fit the blog; here’s the much higher-res picture. It’s beautiful, and you can really see the tail of the comet and Earthshine on the Moon; the dark part of the Moon lit by reflected light from Earth.

Zooming in on the comet itself.  
Image credit: Adam Block

Next up is a nice close-up of the comet by Adam Block (whose images have graced this blog many times before). He didn’t use a telescope though! This is once again a Canon 40D, but with a 300 mm lens. The detail in the tail is amazing; you can see the thin ion tail flying straight back from the comet and the much broader dust tail fanning out. He also got a lovely wide-field shot of the comet and the Moon, too.

Finally, this next image is a jaw-dropper: It’s from the sun-observing STEREO B spacecraft—I wrote quite a bit about this the other day—and with some digital processing the image shows multiple rays in the tail streaking away from the comet. STEREO saw something very similar to this in comet McNaught back in 2007, and trust me, you want to see that!

Comet Pan-STARRS seen from the Sun-observing spacecraft  STEREO B. Note the rays fanning out in the tail.
Image credit: NASA/STEREO via SungrazerComets on Twitter.

Pan-STARRS should be visible for the next couple of weeks, moving north but getting fainter as it does so. It passed the Sun on March 10, and as it moves away the illumination drops, so it dims. As you can see in the diagram below, its orbit is nearly perpendicular to Earth’s (the dark blue line is when it was south of the Earth’s orbital plane, and light blue is north). The path it’s taking is nearly face-on to us, so it never gets any closer than it is now, and it’s moving nearly straight up, out of the Earth’s orbital plane, so the distance to it is increasing rapidly. By April it will have faded considerably, and may dim to below naked eye visibility by mid-April.

The orbits of Pan-STARRS and the inner planets. See text for details.
Image credit: NASA/JPL

So go out and see it while you can! You hardly even need a map (though here’s one from Sky and Telescope and another at Astronomy magazine that will help). It should be visible about a half hour after sunset (earlier if you have binoculars) to the west. I’ll note that for folks with decent binoculars and/or cameras, the planet Uranus is pretty close to Pan-STARRS as well. Dean Ketelsen was able to see it in the pictures he took on Mar. 12!

And if you want to see even more pictures, point your browser to SpaceWeather.com and UniverseToday, which have amazing pictures for show and tell, too.

And don’t fret: If you miss this one, Comet ISON is coming this fall…