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There have been relatively few good comets in recent years, but 2013 promises to be an excellent year. Discovered in September 2012, Comet ISON (C/2012 S1) is predicted to be sensational at the end of 2013. There is even talk of this wonder object becoming perhaps the greatest comet of recorded times – a comet of the century or even millennium, blazing a spectacular trail in sky, easily visible in daylight and for a short time brighter than even the full Moon!!

Of course, seasoned astronomers and comet watches know only too well how extremely unpredictable comets are. Probably the most famous flop of all time was Comet Kohoutek of 1973/74. Just like ISON, Kohoutek was hyped as the "comet of the century", but despite putting on a fairly decent show, it fell well short of expectations.

Therefore, only time will tell if ISON lives up to the hype. Before then and to whet the appetite, there is another bright comet currently on its way. This comet is named PanSTARRS (C/2011 L4) and although it's predicted to be nowhere near as brilliant as ISON, it should still be spectacular during the first part of 2013.


Comet PanSTARRS was discovered on June 6, 2011 using the Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) located on the island of Maui in Hawaii. At discovery, the comet had an apparent magnitude of 19 and was located at a distance of about 700 million miles (1.2 billion km) from the Sun, beyond the orbit of Jupiter.

Pan-STARRS discovery image of Comet C/2011 L4 (PANSTARRS). The comet is shown by the red arrow.(Institute for Astronomy/University of Hawaii/Pan-STARRS)

The Pan-STARRS project is in its infancy and eventually will use an array of four 1.8m astronomical telescopes to survey the sky continuously in the hunt for moving objects. Despite only one of the four telescopes currently up and running, the project is producing great results to date and when more of the telescopes come online, a flurry of asteroid and comet discoveries should occur.

The orbit of comet PanSTARRS is parabolic and its origins are from within the Oort Cloud. The orbital period is estimated to be 110,000 years, so when it does arrive in the inner solar system this will be a once in a life time apparition.

Location, magnitude and star chart

In June 2012, one year after discovery PanSTARRS had brightened to 13th magnitude and hence within visual range for large amateur telescopes. At the beginning of December 2012, it attained 9th magnitude and therefore could be spotted with small telescopes or binoculars. The comet continues to increase gradually in brightness and by the end of 2012 is predicted to reach 8th magnitude.

Interestingly, recent observations indicate that the comet is quite large and has a particularly active nucleus. Recent images show it slightly brighter than expected, with a coma and tail despite its great distance. This bodes extremely well for a great show in 2013.

The real fun begins around February, when if all goes well PanSTARRS will be visible to the naked eye. It should then peak in brightness on March 10th at magnitude -1. On this date, perihelion (closest approach to the Sun) occurs and the comet will be just 0.3016 AU (45.1 million kms or 28.2 million) from the Sun. A few days earlier on March 5, PanSTARRS makes its closest approach to Earth at 1.09 AU (163.1 million kms or 101.9 million miles). The comet then decreases in magnitude as it moves away, but should still remain a naked eye object for another 6 weeks or so.

Over the next few months, PanSTARRS travels through a number of constellations. From now (December 2012) until the end of February it is located in the southern section of the sky; starting in Scorpius, before moving into Corona Australis, then Telescopium, Microscopium, Grus, Piscis Austrinus and finally into Sculptor. The comet then moves sharply north into Aquarius, before climbing through Cetus, Pisces, Andromeda, Cassiopeia, Cepheus and ending May in Draco. At this time, for almost the entire northern hemisphere the comet will be circumpolar. With a peak declination of 85 degrees north, it will be located just shy of Polaris (α UMi) and the North Celestial Pole.

The chart below shows the position of PanSTARRS until the end of January 2013.

Finder Chart for Comet PanSTARRS from December 2012 to January 2013

Finder Chart for Comet PanSTARRS from December 2012 to January 2013 - pdf format

Current visibility

Southern hemisphere observers have the first look at PanSTARRS beginning in late December, when it appears as a morning twilight object low down towards the east. In the Northern Hemisphere, it remains unobservable for a long time (until March 2013), since it is either too near to the Sun or too low in the sky to be readily observed.


NameC/2011 L4 (PANSTARRS)
Discovered ByPan-STARRS
Discovery DateJune 6, 2011
EpochFeb 4, 2012
Aphelion (AU)unknown
Perihelion (AU)0.3016
Orbital Period (years)~110,000
Inclination (degrees)84.19
Next perihelionMarch 10, 2013

Comet PanSTARRS (C/2011 L4) Data Table (data shown at 0:00 UT)

DateRight Ascension (J2000)Declination (J2000)Estimated MagnitudeDistance (AU)Constellation
14 Dec 201216h 37m 45s-35d 54m 49s9.02.815Scorpius
15 Dec 201216h 39m 38s-36d 05m 10s9.02.795Scorpius
16 Dec 201216h 41m 33s-36d 15m 37s8.92.775Scorpius
17 Dec 201216h 43m 29s-36d 26m 10s8.92.755Scorpius
18 Dec 201216h 45m 28s-36d 36m 49s8.82.734Scorpius
19 Dec 201216h 47m 28s-36d 47m 34s8.72.714Scorpius
20 Dec 201216h 49m 30s-36d 58m 26s8.72.693Scorpius
21 Dec 201216h 51m 35s-37d 09m 25s8.62.672Scorpius
22 Dec 201216h 53m 41s-37d 20m 29s8.62.650Scorpius
23 Dec 201216h 55m 50s-37d 31m 40s8.52.629Scorpius
24 Dec 201216h 58m 01s-37d 42m 58s8.52.607Scorpius
25 Dec 201217h 00m 15s-37d 54m 22s8.42.585Scorpius
26 Dec 201217h 02m 31s-38d 05m 53s8.32.563Scorpius
27 Dec 201217h 04m 49s-38d 17m 29s8.32.541Scorpius
28 Dec 201217h 07m 11s-38d 29m 13s8.22.518Scorpius
29 Dec 201217h 09m 35s-38d 41m 02s8.12.496Scorpius
30 Dec 201217h 12m 02s-38d 52m 58s8.12.473Scorpius
31 Dec 201217h 14m 32s-39d 04m 60s8.02.450Scorpius
01 Jan 201317h 17m 05s-39d 17m 08s7.92.427Scorpius
02 Jan 201317h 19m 42s-39d 29m 21s7.92.403Scorpius
03 Jan 201317h 22m 22s-39d 41m 41s7.82.380Scorpius
04 Jan 201317h 25m 06s-39d 54m 06s7.72.356Scorpius
05 Jan 201317h 27m 53s-40d 06m 36s7.72.332Scorpius
06 Jan 201317h 30m 44s-40d 19m 12s7.62.308Scorpius
07 Jan 201317h 33m 39s-40d 31m 52s7.52.284Scorpius
08 Jan 201317h 36m 39s-40d 44m 36s7.42.259Scorpius
09 Jan 201317h 39m 43s-40d 57m 25s7.42.235Scorpius
10 Jan 201317h 42m 51s-41d 10m 16s7.32.210Scorpius
11 Jan 201317h 46m 05s-41d 23m 11s7.22.185Scorpius
12 Jan 201317h 49m 23s-41d 36m 08s7.12.160Scorpius
13 Jan 201317h 52m 47s-41d 49m 06s7.02.135Scorpius
14 Jan 201317h 56m 16s-42d 02m 04s7.02.110Scorpius
15 Jan 201317h 59m 51s-42d 15m 02s6.92.085Corona Australis
16 Jan 201318h 03m 32s-42d 27m 59s6.82.060Corona Australis
17 Jan 201318h 07m 20s-42d 40m 53s6.72.034Corona Australis
18 Jan 201318h 11m 14s-42d 53m 42s6.62.009Corona Australis
19 Jan 201318h 15m 16s-43d 06m 26s6.51.983Corona Australis
20 Jan 201318h 19m 24s-43d 19m 01s6.41.957Corona Australis
21 Jan 201318h 23m 40s-43d 31m 27s6.31.932Corona Australis
22 Jan 201318h 28m 05s-43d 43m 41s6.21.906Corona Australis
23 Jan 201318h 32m 38s-43d 55m 41s6.11.880Corona Australis
24 Jan 201318h 37m 19s-44d 07m 22s6.01.854Corona Australis
25 Jan 201318h 42m 11s-44d 18m 43s5.91.828Corona Australis
26 Jan 201318h 47m 11s-44d 29m 40s5.81.803Corona Australis
27 Jan 201318h 52m 22s-44d 40m 08s5.71.777Corona Australis
28 Jan 201318h 57m 44s-44d 50m 03s5.61.751Corona Australis
29 Jan 201319h 03m 16s-44d 59m 21s5.51.725Corona Australis
30 Jan 201319h 09m 01s-45d 07m 55s5.41.700Corona Australis
31 Jan 201319h 14m 57s-45d 15m 39s5.31.674Corona Australis

See also

Final swan song for Comet PanSTARRS (C/2011 L4)
Comet PanSTARRS (C/2011 L4) heads towards a close pass by of Polaris, the Northern Pole Star
Comet PanSTARRS (C/2011 L4) moves through Cassiopeia
Comet PanSTARRS (C/2011 L4) starts to fade but remains a naked eye and binocular target
Media Frenzy as Comet PanSTARRS (C/2011 L4) is now visible to observers in the Northern Hemisphere
How to see Comet PanSTARRS (C/2011 L4) in March 2013
Comet PanSTARRS (C/2011 L4) edges closer to March evening performance
Comet PanSTARRS (C/2011 L4) on the verge of naked eye visibility