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Comet PanSTARRS is now no longer a naked eye object but remains visible for some time through amateur telescopes. Having recently passed within a few degrees of the spectacular Andromeda Galaxy (M31), the comet has now moved into Cassiopeia and will next pass through the "W" shape before leaving the constellation at the end of April.

The bright constellation Cassiopeia lies in the far northern sky and is easily recognisable due to its distinctive "W" shape. It's bordered by Andromeda (to the south), Perseus (southeast) and Cepheus (north) and is located on the opposite side of the polar region to the "Big Dipper" or "Plough" asterism of Ursa Major. The "W" of Cassiopeia is circumpolar and hence never sets for observers located at latitudes greater than 45N.

Comet PanSTARRS and M31 on March 30, 2013 (Image credit - Pavel Smilyk)

PanSTARRS entered into Cassiopeia on April 9th. On this date it was right at the limit of naked eye visibility (mag. 6.2) but an easy binocular and small telescope target. The comet is continuing on an almost direct northern path, roughly parallel to the zero hour of right ascension. On April 16th, PanSTARRS passed less than 2 degrees west of ζ Cas (mag. 3.7) and λ Cas (mag. 4.7). It then reaches the vicinity of the "W" around April 19th, passing 2.5 degrees west of Schedar (α Cas - mag. 2.2). Two day later PanSTARRS crosses the line connecting the western two stars of the "W", Schedar and Caph (β Cas - mag. 2.3) before passing 1.25 degrees west of mag. 6.5 open cluster NGC 129 on April 23rd. It's predicted that it will now be down to magnitude 7.5, hence a more difficult binocular object but still well within the range of small and medium sized telescopes. On April 30th, PanSTARRS finally leaves Cassiopeia and moves into adjacent Cepheus.

Finder Chart for Comet PanSTARRS as it moves through Cassiopeia

Finder Chart for Comet PanSTARRS as it moves through Cassiopeia - pdf format

Finder Chart for Comet PanSTARRS - April 3, 2013 to April 21, 2013

Finder Chart for Comet PanSTARRS - April 3, 2013 to April 21, 2013 - pdf format

From temperate northern latitudes, PanSTARRS is circumpolar and therefore visible all night. When viewed around midnight or preferably during the early hours of the morning, it's relatively high in the sky and therefore easier to see.


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

DateRight AscensionDeclinationMag.Distance from Earth (AU)Constellation
09 Apr 201300h 27m 36s46d 03m 18s6.21.342Andromeda
10 Apr 201300h 27m 07s47d 08m 44s6.21.350Cassiopeia
11 Apr 201300h 26m 39s48d 13m 08s6.31.358Cassiopeia
12 Apr 201300h 26m 09s49d 16m 34s6.41.367Cassiopeia
13 Apr 201300h 25m 39s50d 19m 06s6.51.375Cassiopeia
14 Apr 201300h 25m 09s51d 20m 46s6.61.383Cassiopeia
15 Apr 201300h 24m 37s52d 21m 39s6.71.392Cassiopeia
16 Apr 201300h 24m 05s53d 21m 45s6.81.400Cassiopeia
17 Apr 201300h 23m 31s54d 21m 08s6.91.408Cassiopeia
18 Apr 201300h 22m 56s55d 19m 49s7.01.417Cassiopeia
19 Apr 201300h 22m 20s56d 17m 52s7.11.425Cassiopeia
20 Apr 201300h 21m 41s57d 15m 17s7.21.433Cassiopeia
21 Apr 201300h 21m 01s58d 12m 07s7.31.442Cassiopeia
22 Apr 201300h 20m 19s59d 08m 22s7.41.450Cassiopeia
23 Apr 201300h 19m 34s60d 04m 05s7.51.459Cassiopeia
24 Apr 201300h 18m 46s60d 59m 17s7.61.467Cassiopeia
25 Apr 201300h 17m 55s61d 53m 58s7.71.476Cassiopeia
26 Apr 201300h 17m 00s62d 48m 10s7.81.485Cassiopeia
27 Apr 201300h 16m 02s63d 41m 53s7.91.493Cassiopeia
28 Apr 201300h 14m 59s64d 35m 09s8.01.502Cassiopeia
29 Apr 201300h 13m 52s65d 27m 58s8.11.511Cassiopeia
30 Apr 201300h 12m 38s66d 20m 20s8.21.519Cassiopeia
01 May 201300h 11m 19s67d 12m 17s8.31.528Cepheus
02 May 201300h 09m 53s68d 03m 48s8.41.537Cepheus
03 May 201300h 08m 19s68d 54m 53s8.51.546Cepheus
04 May 201300h 06m 36s69d 45m 32s8.61.555Cepheus
05 May 201300h 04m 43s70d 35m 46s8.71.564Cepheus
06 May 201300h 02m 39s71d 25m 33s8.81.574Cepheus
07 May 201300h 00m 22s72d 14m 54s8.91.583Cepheus
08 May 201323h 57m 50s73d 03m 48s9.01.592Cepheus
09 May 201323h 55m 02s73d 52m 12s9.11.602Cepheus
10 May 201323h 51m 54s74d 40m 07s9.21.611Cepheus
11 May 201323h 48m 24s75d 27m 29s9.31.621Cepheus
12 May 201323h 44m 29s76d 14m 18s9.41.631Cepheus
13 May 201323h 40m 03s77d 00m 30s9.51.641Cepheus
14 May 201323h 35m 02s77d 46m 01s9.51.650Cepheus
15 May 201323h 29m 19s78d 30m 47s9.61.661Cepheus
16 May 201323h 22m 47s79d 14m 43s9.71.671Cepheus
17 May 201323h 15m 16s79d 57m 41s9.71.681Cepheus
18 May 201323h 06m 35s80d 39m 33s9.81.691Cepheus
19 May 201322h 56m 28s81d 20m 06s9.81.702Cepheus
20 May 201322h 44m 40s81d 59m 06s9.91.712Cepheus
21 May 201322h 30m 49s82d 36m 14s10.01.723Cepheus
22 May 201322h 14m 31s83d 11m 04s10.01.734Cepheus
23 May 201321h 55m 19s83d 43m 05s10.11.745Cepheus
24 May 201321h 32m 47s84d 11m 36s10.11.756Cepheus
25 May 201321h 06m 39s84d 35m 48s10.21.767Cepheus
26 May 201320h 36m 52s84d 54m 48s10.31.778Draco
27 May 201320h 03m 57s85d 07m 42s10.31.790Draco
28 May 201319h 29m 01s85d 13m 49s10.41.801Draco
29 May 201318h 53m 40s85d 12m 50s10.41.813Draco
30 May 201318h 19m 37s85d 04m 57s10.51.825Draco
31 May 201317h 48m 17s84d 50m 50s10.51.837Draco
01 Jun 201317h 20m 25s84d 31m 23s10.61.849Ursa Minor
02 Jun 201316h 56m 15s84d 07m 34s10.61.861Ursa Minor
03 Jun 201316h 35m 35s83d 40m 20s10.71.873Ursa Minor
04 Jun 201316h 18m 02s83d 10m 27s10.71.886Ursa Minor
05 Jun 201316h 03m 10s82d 38m 31s10.81.898Ursa Minor
06 Jun 201315h 50m 32s82d 05m 02s10.81.911Ursa Minor
07 Jun 201315h 39m 48s81d 30m 24s10.91.924Ursa Minor
08 Jun 201315h 30m 37s80d 54m 53s10.91.937Ursa Minor
09 Jun 201315h 22m 43s80d 18m 43s11.01.950Ursa Minor
10 Jun 201315h 15m 55s79d 42m 04s11.01.964Ursa Minor
11 Jun 201315h 10m 01s79d 05m 06s11.11.977Ursa Minor
12 Jun 201315h 04m 53s78d 27m 53s11.11.991Ursa Minor
13 Jun 201315h 00m 24s77d 50m 32s11.22.004Ursa Minor
14 Jun 201314h 56m 29s77d 13m 07s11.22.018Ursa Minor
15 Jun 201314h 53m 02s76d 35m 41s11.32.032Ursa Minor
16 Jun 201314h 49m 60s75d 58m 17s11.32.047Ursa Minor
17 Jun 201314h 47m 20s75d 20m 58s11.42.061Ursa Minor
18 Jun 201314h 44m 58s74d 43m 44s11.42.075Ursa Minor
19 Jun 201314h 42m 54s74d 06m 39s11.52.090Ursa Minor
20 Jun 201314h 41m 03s73d 29m 43s11.52.104Ursa Minor
21 Jun 201314h 39m 26s72d 52m 58s11.62.119Ursa Minor
22 Jun 201314h 38m 01s72d 16m 23s11.62.134Ursa Minor
23 Jun 201314h 36m 45s71d 40m 02s11.72.149Ursa Minor
24 Jun 201314h 35m 39s71d 03m 53s11.72.165Ursa Minor
25 Jun 201314h 34m 42s70d 27m 58s11.82.180Ursa Minor
26 Jun 201314h 33m 52s69d 52m 17s11.82.195Ursa Minor
27 Jun 201314h 33m 08s69d 16m 50s11.82.211Ursa Minor
28 Jun 201314h 32m 31s68d 41m 38s11.92.227Ursa Minor
29 Jun 201314h 32m 00s68d 06m 42s11.92.243Ursa Minor
30 Jun 201314h 31m 34s67d 32m 01s12.02.259Ursa Minor
01 Jul 201314h 31m 13s66d 57m 35s12.02.275Ursa Minor
02 Jul 201314h 30m 56s66d 23m 26s12.12.291Ursa Minor
03 Jul 201314h 30m 43s65d 49m 33s12.12.307Ursa Minor
04 Jul 201314h 30m 35s65d 15m 56s12.12.324Draco
05 Jul 201314h 30m 29s64d 42m 35s12.22.340Draco
06 Jul 201314h 30m 27s64d 09m 32s12.22.357Draco
07 Jul 201314h 30m 28s63d 36m 45s12.32.374Draco
08 Jul 201314h 30m 32s63d 04m 14s12.32.391Draco
09 Jul 201314h 30m 39s62d 32m 01s12.42.408Draco
10 Jul 201314h 30m 48s62d 00m 05s12.42.425Draco
11 Jul 201314h 30m 59s61d 28m 26s12.42.442Draco
12 Jul 201314h 31m 12s60d 57m 05s12.52.460Draco
13 Jul 201314h 31m 28s60d 26m 00s12.52.477Draco
14 Jul 201314h 31m 45s59d 55m 13s12.62.495Draco
15 Jul 201314h 32m 05s59d 24m 43s12.62.512Draco
16 Jul 201314h 32m 26s58d 54m 31s12.62.530Draco
17 Jul 201314h 32m 49s58d 24m 35s12.72.548Draco
18 Jul 201314h 33m 13s57d 54m 57s12.72.566Draco
19 Jul 201314h 33m 38s57d 25m 37s12.82.584Draco
20 Jul 201314h 34m 05s56d 56m 33s12.82.602Draco
21 Jul 201314h 34m 34s56d 27m 47s12.82.620Draco
22 Jul 201314h 35m 03s55d 59m 17s12.92.639Draco
23 Jul 201314h 35m 34s55d 31m 05s12.92.657Draco
24 Jul 201314h 36m 06s55d 03m 10s13.02.675Draco
25 Jul 201314h 36m 39s54d 35m 31s13.02.694Boötes
26 Jul 201314h 37m 13s54d 08m 09s13.02.712Boötes
27 Jul 201314h 37m 48s53d 41m 04s13.12.731Boötes
28 Jul 201314h 38m 23s53d 14m 16s13.12.750Boötes
29 Jul 201314h 38m 60s52d 47m 43s13.12.769Boötes
30 Jul 201314h 39m 38s52d 21m 27s13.22.788Boötes
31 Jul 201314h 40m 16s51d 55m 28s13.22.806Boötes

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) 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
Comet PanSTARRS (C/2011 L4) brightens to within binocular range