Comet PanSTARRS (C/2011 L4) peaked out at roughly magnitude +1 and is now fading with a very wide tail. We covered the comet in the February and March 2013 issues of Sky & Telescope. Here's the latest:
April 23: Crossing Cassiopeia. The comet is heading north, in Cassiopeia through the end of April. It's much better seen (from north temperate latitudes) before dawn now than after dusk. The comet has faded to about 6th magnitude, detectable in binoculars and very respectable in a telescope. Use the finder chart in the March Sky & Telescope, page 51.
Its tail has grown hugely wide! It's a fan spanning 160° in this photo of the comet passing the irregular galaxy IC 10, taken remotely by Rolando Ligustri on April 22nd.
April 10. It's moving farther north and fading on schedule, now 4th or 5th magnitude. Here are images from April 1 to 10 taken from the Orkney Islands, Scotland, by John C. Vetterlein of the Auroral & Magnetic Observatory in Rousay, latitude 59° north, where the comet is nicely circumpolar.
April 2. The comet passes the Andromeda Galaxy in the first week of April. They're closest (2° apart) on the evening of the 3rd and morning of the 4th. See article, Comet PanSTARRS Offers M31 Photo Op.
March 29. From Norway comes the gorgeous picture below, as PanSTARRS approaches the Andromeda Galaxy.
March 21. Last night Sean Walker, Sky & Telescope's imaging editor, took the shot below:
Walker writes, "Tried some wide-field shots tonight. Should have brought a slightly longer lens! 18-55mm zoom lens at 55mm, ISO 800; 60-second exposure with 0.5x tracking."
March 20: Broadening tail. The farther north you are now, the higher the fading comet appears in twilight and the darker the sky you can see it in. As predicted, this means that imagers are becoming able to capture more of the comet's big, wide, detail-filled tail — though its surface brightness is mostly too low to be seen visually.
For instance, last night Michael Jaeger in Austria (latitude 48° north) took the dramatic image below with the sky background suppressed and contrast enhanced.
March 18: Fading but higher. John Bortle writes, "I've been troubled for days regarding the broad range in reported magnitudes for this comet in recent days. Some ranked it near zero magnitude, while so many were indicating the comet was difficult or impossible to detect with the unaided eye.
Well, last evening [March 17th] I settled the matter as far as I am concerned. From careful observation I determined a total magnitude for the comet's head of only +2.6 , noting that even in a very clear sky the comet was only glimpsed with the unaided eye as twilight deepened. In my opinion the general lack of good comparison stars nearby has led to observers going far afield to stars much higher up for comparison, and then applying excessive atmospheric-extinction corrections to their estimates."
Many others disagree. Alan Whitman writes: "In my Canon 10x30 IS binoculars in excellent transparency, the nucleus was FAR brighter than adjacent magnitude 2.8 Gamma Pegasi. Magnitude 1 is a lot closer to its current magnitude, in my opinion."
Impressive time-lapse movie of PanSTARRS from the STEREO-B Sun-observing spacecraft, with coronal mass ejections passing by.
March 14: A little star with a dim tail. Many, many people saw it last evening, aided by the crescent Moon, but many others failed. S&T's Tony Flanders writes: "I caught it from the balcony of my mother's apartment at 7:55, 54 minutes after sunset [at latitude 41° N]. I'm sure I would have spotted it much, much earlier except that I had been looking too high, too far left, and for a very different kind of object.
"I'm sure this comet will never be obvious to the unaided eye from our latitude, much less spectacular. But it sure is a beauty through my 10x30 image-stabilized binoculars. I was looking for something larger and more diffuse; in fact, it's tiny and intensely bright, with a nearly stellar head (at 10x) and a short, very bright tail."
From S&T's Sean Walker at 43° N: "I was able to observe the comet with 70mm spotting scope and shared some great views with about 30 people. The comet was naked-eye visible, though barely, from about [50 minutes after sunset] until it was in the trees 15 minutes later.
"Not much of a tail, perhaps 1° with averted vision naked-eye. Never obvious; it was very reminiscent of the views we had in 2007 of Comet McNaught, though fainter. Still very orange due to low altitude.
"This photo by UK amateur Jamie Cooper approximates the view through a small telescope perfectly. It looked exactly like this in my 70mm f/5 spotting scope:"
And from S&T editor Bob Naeye: "The comet was barely visible to the naked eye, and when I say 'barely,' I mean 'barely!' It was quite noticeable, however, in binocs. The coma was fairly bright and the tail was obvious. It was lovely through binocs.
"But I agree with Tony that this will never be a showstopper. Edwin, Imelda, and I pointed out the comet to several passersby, and they had a very, very difficult time seeing it naked-eye, and also had difficulty finding it through binocs. And yet they had the three of us standing right next to them explaining in detail where to look. We also had airplanes in the sky right near the comet, and we used the positions of those planes to help these passersby find the comet."
Tonight, March 14th, look about two fist-widths at arm's length below the crescent Moon and perhaps a bit right.
March 13: To the Moon! It's getting easier now; each evening the comet is a little less low in the twilight. Last night lots of photographers shot the little "smudge of light" with the thin crescent Moon:
In tonight's twilight, look for the comet a fist-width at arm's length below the thicker Moon. Best view is roughly 40 minutes after sunset. You'll need an open view low due west.
Another nice Moon-and-comet pic from Fred Espenak, plus a movie of the two setting.
March 11: Speck, not spectacle. Last night lots of people in the north temperate latitudes finally began picking up the comet for the first time, but usually with binoculars, and only if they knew just where to look. Keep trying. It's moving a little higher out of the bright depths of twilight every day now.
This image matches a lot of people's visual impressions: