Free Republic

Explanation: Once known as Earth's sunset comet, PanSTARRS (C/2011 L4) is up all night now, but only for northern hemisphere skygazers. Telescopes are required to track its progress as it fades and heads for the outer solar system. But because planet Earth passed through the comet's orbital plane in late May, PanSTARRS will also be remembered for its remarkably long anti-tail. That edge-on perspective looking along the broad, fanned-out dust tail as it trailed behind the comet created the appearance of an anti-tail pointing in the sunward direction, back toward the inner solar system. Recorded on the night of May...

Explanation: Once the famous sunset comet, PanSTARRS (C/2011 L4) is now visible all night from much of the northern hemisphere, bound for the outer solar system as it climbs high above the ecliptic plane. Dimmer and fading, the comet's broad dust tail is still growing, though. This widefield telescopic image was taken against the starry background of the constellation Cepheus on May 15. It shows the comet has developed an extensive anti-tail, dust trailing along the comet's orbit (to the left of the coma), stretching more than 3 degrees across the frame. Since the comet is just over 1.6 astronomical...

Explanation: The broad dust tail of Comet PanSTARRS (C/2011 L4) has become a familiar sight for many northern hemisphere comet watchers, as the comet fades but rises higher above the western horizon after sunset. This view of the popular comet may seem a little fantastic, though. Sweeping away from the Sun and trailing behind the comet's orbit, the curving dust tail also seems to stream away from a shining mountaintop castle. Comet Castle might be an appropriate name in this scene, but its traditional name is Castle Hohenzollern. Taken on March 15 with an extreme telephoto lens, the Comet Castle...

Explanation: Sweeping quickly through southern skies on March 5, Comet PanSTARRS (C/2011 L4) follows the Sun toward the western horizon in this twilight scene. In the foreground is Australia's CSIRO Parkes Radio Telescope, a 64 meter wide steerable dish that is no stranger to the space age exploration of comets. In March of 1986 the Parkes dish tracked ESA's Giotto spacecraft as it flew by Comet Halley and received the first ever closeup images of Halley's nucleus. At naked-eye visibility, Comet PanSTARRS made its closest approach to planet Earth on March 5. Its closest approach to the Sun will be...

The icy mass, called C/2011 L4 Pan-Starrs, should be visible with binoculars or a telescope from 8 March. But in the following days, it will become even brighter and could be seen with the naked eye. Astronomers in the Southern Hemisphere have already been treated to a fly past, with reports that the body was as bright as stars in the Plough. The comet was first discovered in June 2011, spotted by the Pan-Starrs telescope (hence its name) in Hawaii as a faint object more than a billion kilometres away. Astronomers believe it originated in the Oort Cloud, a region...

Explanation: Two impressive comets will both reach their peak brightness during the next two weeks. Taking advantage of a rare imaging opportunity, both of these comets were captured in the sky together last week over the Atacama desert in South America. Comet C/2012 F6 (Lemmon), visible on the upper left of the above image, is sporting a long tail dominated by glowing green ions. Comet C/2011 L4 (PanSTARRS), visible near the horizon on the lower right, is showing a bright tail dominated by dust reflecting sunlight. The tails of both comets point approximately toward the recently set Sun. Comet Lemmon...

Explanation: For now, Comet Lemmon (C/2012 F6a), and Comet PanSTARRS (C/2011 L4) are sweeping through southern skies. Lemmon's lime green coma and thin tail are near the left edge of this telephoto scene, a single frame from a timelapse video (vimeo here) recorded on February 12, tracking its motion against the background stars. Comet Lemmon's path brought it close to the line-of-sight to prominent southern sky treasures the Small Magellanic Cloud and globular cluster 47 Tucanae (right). Sporting a broader, whitish tail, Comet PanSTARRS appears in later video frames moving through the faint constellation Microscopium. Visible in binoculars and small...

Icy body may even be bright enough to be seen in the day, expert says. Astronomers stumbled upon the icy interloper on June 5 while searching for potentially hazardous asteroids. Equipped with the world's largest digital camera—1,400 megapixels—the University of Hawaii's Pan-STARRS team snagged a faint image of the odd object while it was more than 700 million miles (1.1 billion kilometers) away, between the orbits of Jupiter and Saturn. By March 2013 the comet, named C/2011 L4 (PANSTARRS), is expected to come within 30 million miles (48 million kilometers) of the sun—closer even than the innermost planet, Mercury. [snip]...