
Minoru Yoneto
Minoru Yoneto captured this picture of Comet PanSTARRS shining over Queenstown, New Zealand, on March 2. The comet's tail has two components, consisting of glowing gas and shining dust. Yoneto told SpaceWeather.com that "it's a splendid appearance."
Observers in the Southern Hemisphere have been watching Comet PanSTARRS for weeks, but the Northern Hemisphere is due to get its first looks at one of the year's most eagerly anticipated sky extravaganzas this week. And there's good news for northerners: The up-and-down expectations for the cometary show are trending upward again.
"In the Southern Hemisphere we have a few days to enjoy it," Argentine photographer Victor Gabriel Bibe, one of many observers who have been tracking the comet's brightening glow, said in an email.
On Tuesday, PanSTARRS makes its closest approach to Earth. On Thursday or so, it should start becoming visible to Northern Hemisphere observers in the western sky, low to the horizon just after sunset. The best photo ops will come March 12 and 13, when PanSTARRS pairs up with the crescent moon.
The brightness of an astronomical object is measured by magnitude, with lower numbers denoting brighter objects. Magnitude +6 is about the limit for naked-eye observations under prime conditions. Magnitude +2 is equivalent to the brightness of Polaris, the North Star. Early on, astronomers said PanSTARRS could get to magnitude zero, putting it in a league with some of the brightest stars in the sky. More recently, they noted that the comet wasn't brightening as quickly as they originally thought and revised the forecast to around +2. Now, the consensus is that it could get to +1 or brighter — maybe not dazzling, but definitely not bad.
"As long as it continues its behavior for a few days, it looks like the Northern Hemisphere — even us city-dwellers — might get a pretty good view of this thing," said Karl Battams of the Naval Research Laboratory in Washington.
The comet was discovered in June 2011 by the Panoramic Survey Telescope and Rapid Response System, or Pan-STARRS, in Hawaii — which helps explain the genesis of its official name, Comet C/2011 L4 (PanSTARRS). The "C" means that the comet is considered a non-periodic newbie, coming in for the first time from the Oort Cloud on the solar system's edge. The "L4" means it was the fourth comet discovered during the first half of June.

Victor Gabriel Bibe
Comet PanSTARRS shines above a mountain range in Tierra del Fuego, Argentina. The picture was taken by Ushuaia photographer Victor Gabriel Bibe. For more of Bibe's pictures, check out El Cielo de Tierra del Fuego.

Dieter Willasch
Dieter Willasch snapped this picture of Comet PanSTARRS on March 2 from Somerset West in South Africa. Visit Astro-Cabinet for more images by Willasch.

NASA
This chart shows Comet PanSTARRS' location in the Northern Hemisphere evening sky after sunset for several dates during prime time. The position of the crescent moon is shown for March 12. Watch a NASA video about Comet PanSTARRS.
Even though PanSTARRS is still a few days away from Northern Hemisphere visibility, you can take advantage of these tips to maximize your comet-viewing experience:
- Scope out a spot with good western exposure and a minimum of trees, buildings or hills to spoil the view. PanSTARRS won't get very high in the sky, so you'll want to scan the horizon as soon as the sun goes down. But not before! It'd be a tragedy to damage your eyes for the sake of a comet.
- The farther you are from city lights and cloudy weather, the better you'll be able to see the comet. "I was very lucky to observe the comet, because in the area where I live, the weather is very unstable and the sky is always cloudy. Every time the sky clears, I attempt to observe," Bibe said.
- Although the comet is visible to the unaided eye, binoculars will enhance the view — particularly when it comes to seeing the tail. "To the naked eye, this comet has a stellar aspect. But with 10x50 binoculars you can see the tail clearly," Bibe said.
- Once it's visible in the Northern Hemisphere, the comet will rise higher in the sky on each succeeding night. If PanSTARRS follows the expected trend, the viewing should be best between March 10, when it makes its closest approach to the sun, and March 13 or so. After about that time, the glare of the waxing moon could take some of the shine off the comet. PanSTARRS is projected to fade from naked-eye visibility in April.
After PanSTARRS: ISON
PanSTARRS is the first of two comets expected to take the spotlight this year. The other one is Comet ISON, which has the potential to get much, much brighter than PanSTARRS in November. Some experts are hoping it will equal the brightness of the full moon, although Battams says it's way too early to make firm predictions.
To prepare for ISON's arrival, Battams and other researchers are helping NASA organize a comet observing campaign. "We just want to make sure that all the major observatories are aware of this," Battams said.
ISON is expected to pass as close to the sun's surface as 684,000 miles (1.1 million kilometers), which could produce a dramatic brightening of the comet when it swings back out of the inner solar system. It could produce scientific insights as well.
"Sungrazing comets are unique objects that experience the most extreme thermal and gravitation forces our solar system has to offer them," the campaign's Web page says. "However, rarely do we get to see these objects more than a few hours before their demise. Comet ISON offers us the rare opportunity to study a sungrazer in great detail, for an extended period, and place it in the context of other comets."
For updates on the year of the comets, check in with the "Waiting for ISON" blog as well as SpaceWeather.com and the Remanzacco Observatory website, and follow @ISONUpdates on Twitter.
Got comet pictures? Share them via NBC News' FirstPerson photo upload site and we'll pass them along in a future posting.
More about comets:
- NASA probe tracks 'Comet of the Century'
- Comet shows and other sky highlights for 2013
- Flash interactive: Inside a comet
- EarthSky preview for PanSTARRS
- Space.com preview for PanSTARRS
- Sky & Telescope preview for PanSTARRS
Alan Boyle is NBCNews.com's science editor. Connect with the Cosmic Log community by "liking" the log's Facebook page, following @b0yle on Twitter and adding the Cosmic Log page to your Google+ presence. To keep up with Cosmic Log as well as NBCNews.com's other stories about science and space, sign up for the Tech & Science newsletter, delivered to your email in-box every weekday. You can also check out "The Case for Pluto," my book about the controversial dwarf planet and the search for new worlds.


You're the man. Perfect quote.
Maybe this comet will open some new "Doors".
Hey - it's a great time for seeing Comets. These two here on Earth, and then a near miss for Mars in 2014.
You so confident about the miss? JPL labs updated their trajectory and the minimum went from 67,000 miles to 33,000 miles. Furthermore, other labs have combined their data and the minimum went to ZERO. You might want to book those flights to Australia to watch the event of the EON.
Here is another article showing possible 25,700 miles and there is one which shows ZERO:
http://spaceobs.org/en/tag/c2013-a1-siding-spring/
http://www.huffingtonpost.com/201/03/05/comet-c2013-a1-collide-mars-astronomers_n_2810665.html
Sorry I lost the link to the ZERO combined calculations but will find it again.
But this could be the event of the EON if it does indeed hit Mars or one of it's satellites the explosion will be clearly visible from Earth in broad daylight from the southern hemisphere.
It's great to recognize the possibility of a Martian impact, and educational to model the potential "impact" (pardon the pun) of such an impact, but it's also prudent to point out that given the best knowledge we have today the chance of Mars "taking one for the team" is very, very small.
As we gather more observations we'll tighten up the path of the Siding Spring comet.
Here is the current scatter plot showing the range of possible paths of the comet, using all the possible ranges of the unknown variables:
http://www.webalice.it/alvitagl/Figures/Marsimp.gif
Looking forward to both of these galactic spectacles.
i wish i could look forward to it but unfortunately as we live in the mountains our western horizon(the peaks) range from 10-14,000 feet. consequence, the mountains will block out the comet like a fence in the sky for us and our neighbors. at least we have a much better opportunity to see the one passing next november.
Haven't seen a comet since Hale-Bopp. Looking forward to this. Got a bunch of trees around me house, so will have to drive somewhere to see the low horizon.
hale bopp was amazing. i remember at the time i had my first job after college at kodak in windsor. all of us who worked the night shift that week, when we got off it would still be dark and dozens of us would end up just standing there staring off to the north in amazement. that was one incredible sight and if all predictions hold up so too will be this november's comet appearance which they say will be so bright as to be visible even during the day. not even hale bopp was that bright.
Definitely excited to introduce comets to my children. We're all really hoping to see a good show this year.
Heading out to the garage now to put the scope back together. Thanks Alan.
flying close to a sun you would have to reverse the ship to avoid the light-youd have to shield your eyes
you'd have to fly blind or reverse steering like in a car looking out the back window
fly backwards
or wear really good sunglasses.
Comet C/2013 A1 could be making a name for itself if it hits Mars and dwarf any other events for Millenia. It would be the event of the EON if it happens.