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Comet Lemmon (C/2012 F6) has been delighting observers in recent months while moving through the deep southern constellations. Already, the comet has turned out to be the surprise package of the year so far. When discovered by Alex Gibbs on March 23, 2012 as part of the Mount Lemmon Survey it was extremely faint at magnitude 20.7 and consequently not anticipated to put on much of a show in 2013. However, much to the enjoyment of observers living in the southern hemisphere and the tropics, Lemmon is performing considerably better than expected. It's of the order of a few magnitudes brighter than originally hoped, has recently attained naked eye visibility and continues to improve as it heads towards perihelion (closest approach to the Sun) on March 24, 2013.

Comet Lemmon as it appeared on 28th January 2013 (Rolf Wahl Olsen -

HD animation of Comet Lemmon's movement across the sky (Rolf Wahl Olsen)

Recent observations

As the beginning of February, Comet Lemmon reached naked eye brightness as it moved through Octans and past the South Celestial Pole. By February 11th, it had improved to magnitude 5.4 with a coma of at least 15 arc minutes in diameter along with a small tail. When viewed through 10x50 binoculars, the tail extended in a southeasterly direction for about 0.5 degrees, similar in size to that of the full Moon.

A fantastic visual and photo opportunity occurred between February 14th and 16th when Lemmon slid past the spectacular globular cluster 47 Tucanae and the superb Small Magellanic Cloud (SMC). At time of closest separation, Lemmon was only 4 degrees west of 47 Tucanae with both objects and part of the SMC visible in the same binocular field of view. The comet brightness was magnitude 5.0 and its appearance not too dissimilar to that of 47 Tucanae.

By February 19th, Lemmon had increased in brightness to magnitude 4.7 and although the coma was practically unchanged in size, the tail was now over 1 degree in length. Images revealed the comet in spectacular glory, a bright vivid green in colour with a bright core and a long wispy tail that extended for many degrees.

Location, magnitude and star chart

After passing close by 47 Tucanae and the SMC, Lemmon continued to move through Tucana until February 24th when it enters Phoenix. On this date it is 13 degrees due west of Achernar (mag. 0.45), the brightest star in the long winding constellation of Eridanus.

Continuing on a northern bearing, Lemmon travels through Phoenix until March 10th when it enters Sculptor. The star fields of Phoenix and Sculptor are barren and contain few bright stars. The brightest star of all is Ankaa (α Phe) at magnitude 2.4. On March 8th, Lemmon passes only 5 degrees to the west of Ankaa and at this time it should have brightened to about magnitude 3.5 with a significant tail visible.

The comet then continues on its northern path, running practically parallel to the zero hour line of right ascension. On March 19th / 20th, it will be about 15 degrees to the east of mag. 1.17 Fomalhaut, the brightest star in the constellation of Piscis Austrinus. Lemmon should now also be close to peak brightness. Originally we estimated a high magnitude of 2.4 but based on recent observations it could be more of the order of 3.2.

Lemmon then remains in Sculptor until March 24th, before crossing the border into Cetus. The comet remains in Cetus for the best part of 3 weeks, before arriving in Pisces on April 13th (mag. 4.4). After spending many months in the southern part of the sky, Lemmon finally crosses the celestial equator and moves into northern section on April 20th. Now down to magnitude 5.0, it continues northwards into Andromeda before reaching Cassiopeia on June 21st. At this time, its declination will be almost 50 degrees north and hence circumpolar for many northern hemisphere observers, but now a faint magnitude 10.

The finder charts below show the path of Comet Lemmon against the background stars from February 20 to March 6, 2013 and from March 6 to March 22, 2013.

Finder Chart for Comet Lemmon from February 20, 2013 to March 6, 2013

Finder Chart for Comet Lemmon from February 20, 2013 to March 6, 2013 - pdf format

Finder Chart for Comet Lemmon from March 6, 2013 to March 22, 2013

Finder Chart for Comet Lemmon from March 6, 2013 to March 22, 2013 - pdf format

Current visibility

From the southern hemisphere, Lemmon was fairly high in the southern evening sky for the first two weeks of February and circumpolar for latitudes further south of 20S. From latitude 30 degrees south (the approximate position of Santiago, Cape Town, Perth and Sydney) the comet was 30 degrees above the southern horizon on February 1st at 23:00.

It remained well placed towards the southern / southwestern horizon for most of February. On February 21st, Lemmon was 15 degrees above the south-southwestern horizon at 23:00 and 28 degrees above the same horizon at 21:00. On March 1st, Lemmon will appear 20 degrees above the southwestern horizon at 21:00, about 1.5 hours after sunset. It remains an early evening object into March although now much closer to the horizon. Of course the comet should brighten significantly during this time as it approaches perihelion. For example on March 15th, 1.5 hours after sunset Lemmon will now be only 6 degrees above the southwestern horizon but shine at magnitude 3.3.

Comet Lemmon is not observable in the northern hemisphere until about May. Although fading, it should still be of the order of 6th magnitude.

Comet Lemmon

NameC/2012 L6 (Lemmon)
Discovered ByA. R. Gibbs (Mount Lemmon Survey)
Discovery DateMarch 23, 2012
Discovery Magnitude20.7
EpochSeptember 30, 2012
Aphelion (AU)~1,000
Perihelion (AU)0.7313
Orbital Period (years)~11,000
Inclination (degrees)82.61
Next perihelionMarch 24, 2013

Comet Lemmon (C/2012 F6) Data Table (data shown at 0:00 UT)

DateRight AscensionDeclinationMag.Distance from Earth (AU)Constellation
19 Feb 201323h 52m 26s-65d 57m 54s4.71.053Tucana
20 Feb 201323h 54m 24s-64d 23m 09s4.61.063Tucana
21 Feb 201323h 56m 06s-62d 50m 01s4.51.073Tucana
22 Feb 201323h 57m 36s-61d 18m 30s4.51.084Tucana
23 Feb 201323h 58m 56s-59d 48m 37s4.41.094Tucana
24 Feb 201300h 00m 07s-58d 20m 22s4.31.106Tucana
25 Feb 201300h 01m 10s-56d 53m 44s4.31.117Phoenix
26 Feb 201300h 02m 07s-55d 28m 43s4.21.129Phoenix
27 Feb 201300h 02m 58s-54d 05m 15s4.11.142Phoenix
28 Feb 201300h 03m 43s-52d 43m 20s4.01.154Phoenix
01 Mar 201300h 04m 25s-51d 22m 54s4.01.167Phoenix
02 Mar 201300h 05m 02s-50d 03m 55s3.91.180Phoenix
03 Mar 201300h 05m 36s-48d 46m 21s3.91.193Phoenix
04 Mar 201300h 06m 06s-47d 30m 08s3.81.206Phoenix
05 Mar 201300h 06m 33s-46d 15m 13s3.71.219Phoenix
06 Mar 201300h 06m 58s-45d 01m 34s3.71.233Phoenix
07 Mar 201300h 07m 20s-43d 49m 06s3.61.246Phoenix
08 Mar 201300h 07m 40s-42d 37m 47s3.61.260Phoenix
09 Mar 201300h 07m 58s-41d 27m 34s3.51.274Phoenix
10 Mar 201300h 08m 14s-40d 18m 22s3.51.287Phoenix
11 Mar 201300h 08m 28s-39d 10m 10s3.41.301Sculptor
12 Mar 201300h 08m 41s-38d 02m 54s3.41.314Sculptor
13 Mar 201300h 08m 53s-36d 56m 30s3.41.328Sculptor
14 Mar 201300h 09m 03s-35d 50m 57s3.31.341Sculptor
15 Mar 201300h 09m 12s-34d 46m 10s3.31.354Sculptor
16 Mar 201300h 09m 20s-33d 42m 08s3.31.368Sculptor
17 Mar 201300h 09m 27s-32d 38m 47s3.21.381Sculptor
18 Mar 201300h 09m 34s-31d 36m 06s3.21.393Sculptor
19 Mar 201300h 09m 39s-30d 34m 01s3.21.406Sculptor
20 Mar 201300h 09m 45s-29d 32m 32s3.21.418Sculptor
21 Mar 201300h 09m 49s-28d 31m 34s3.21.430Sculptor
22 Mar 201300h 09m 54s-27d 31m 08s3.21.442Sculptor
23 Mar 201300h 09m 58s-26d 31m 10s3.21.454Sculptor
24 Mar 201300h 10m 02s-25d 31m 40s3.21.466Sculptor
25 Mar 201300h 10m 05s-24d 32m 36s3.21.477Cetus
26 Mar 201300h 10m 09s-23d 33m 56s3.31.488Cetus
27 Mar 201300h 10m 13s-22d 35m 40s3.31.498Cetus
28 Mar 201300h 10m 17s-21d 37m 46s3.31.509Cetus
29 Mar 201300h 10m 21s-20d 40m 13s3.41.519Cetus
30 Mar 201300h 10m 26s-19d 43m 01s3.41.529Cetus
31 Mar 201300h 10m 31s-18d 46m 09s3.41.538Cetus
01 Apr 201300h 10m 36s-17d 49m 36s3.51.547Cetus
02 Apr 201300h 10m 41s-16d 53m 21s3.51.556Cetus
03 Apr 201300h 10m 47s-15d 57m 24s3.61.565Cetus
04 Apr 201300h 10m 54s-15d 01m 45s3.71.573Cetus
05 Apr 201300h 11m 01s-14d 06m 23s3.71.581Cetus
06 Apr 201300h 11m 08s-13d 11m 17s3.81.588Cetus
07 Apr 201300h 11m 17s-12d 16m 28s3.91.596Cetus
08 Apr 201300h 11m 25s-11d 21m 55s4.01.603Cetus
09 Apr 201300h 11m 34s-10d 27m 37s4.01.610Cetus
10 Apr 201300h 11m 44s-09d 33m 35s4.11.616Cetus
11 Apr 201300h 11m 54s-08d 39m 47s4.21.622Cetus
12 Apr 201300h 12m 04s-07d 46m 15s4.31.628Cetus
13 Apr 201300h 12m 16s-06d 52m 56s4.41.634Cetus
14 Apr 201300h 12m 27s-05d 59m 52s4.51.639Pisces
15 Apr 201300h 12m 39s-05d 07m 02s4.61.645Pisces
16 Apr 201300h 12m 52s-04d 14m 25s4.61.650Pisces
17 Apr 201300h 13m 05s-03d 22m 01s4.71.654Pisces
18 Apr 201300h 13m 18s-02d 29m 50s4.81.659Pisces
19 Apr 201300h 13m 31s-01d 37m 51s4.91.663Pisces
20 Apr 201300h 13m 45s-00d 46m 05s5.01.667Pisces
21 Apr 201300h 13m 60s00d 05m 29s5.11.671Pisces
22 Apr 201300h 14m 14s00d 56m 52s5.21.675Pisces
23 Apr 201300h 14m 29s01d 48m 04s5.31.678Pisces
24 Apr 201300h 14m 44s02d 39m 05s5.41.682Pisces
25 Apr 201300h 14m 59s03d 29m 56s5.51.685Pisces
26 Apr 201300h 15m 15s04d 20m 36s5.61.688Pisces
27 Apr 201300h 15m 30s05d 11m 06s5.71.691Pisces
28 Apr 201300h 15m 46s06d 01m 27s5.81.694Pisces
29 Apr 201300h 16m 01s06d 51m 38s5.91.696Pisces
30 Apr 201300h 16m 17s07d 41m 41s6.01.699Pisces
01 May 201300h 16m 33s08d 31m 35s6.11.701Pisces
02 May 201300h 16m 48s09d 21m 20s6.21.703Pisces
03 May 201300h 17m 04s10d 10m 58s6.31.705Pisces
04 May 201300h 17m 19s11d 00m 27s6.41.707Pisces
05 May 201300h 17m 34s11d 49m 50s6.51.709Pisces
06 May 201300h 17m 49s12d 39m 04s6.61.711Pisces
07 May 201300h 18m 04s13d 28m 12s6.61.713Pisces
08 May 201300h 18m 19s14d 17m 13s6.71.715Pisces
09 May 201300h 18m 33s15d 06m 07s6.81.716Pisces
10 May 201300h 18m 47s15d 54m 55s6.91.718Pisces
11 May 201300h 18m 60s16d 43m 37s7.01.719Pisces
12 May 201300h 19m 13s17d 32m 12s7.11.721Pisces
13 May 201300h 19m 25s18d 20m 41s7.21.722Pisces
14 May 201300h 19m 37s19d 09m 05s7.31.723Pisces
15 May 201300h 19m 48s19d 57m 23s7.41.725Pisces
16 May 201300h 19m 59s20d 45m 35s7.41.726Pisces
17 May 201300h 20m 08s21d 33m 41s7.51.727Pisces
18 May 201300h 20m 17s22d 21m 42s7.61.728Andromeda
19 May 201300h 20m 26s23d 09m 38s7.71.730Andromeda
20 May 201300h 20m 33s23d 57m 28s7.81.731Andromeda
21 May 201300h 20m 40s24d 45m 13s7.91.732Andromeda
22 May 201300h 20m 45s25d 32m 52s7.91.733Andromeda
23 May 201300h 20m 50s26d 20m 26s8.01.734Andromeda
24 May 201300h 20m 54s27d 07m 54s8.11.736Andromeda
25 May 201300h 20m 56s27d 55m 17s8.21.737Andromeda
26 May 201300h 20m 58s28d 42m 35s8.31.738Andromeda
27 May 201300h 20m 58s29d 29m 46s8.31.739Andromeda
28 May 201300h 20m 57s30d 16m 52s8.41.741Andromeda
29 May 201300h 20m 54s31d 03m 52s8.51.742Andromeda
30 May 201300h 20m 50s31d 50m 46s8.61.743Andromeda
31 May 201300h 20m 45s32d 37m 34s8.61.745Andromeda
01 Jun 201300h 20m 38s33d 24m 15s8.71.746Andromeda
02 Jun 201300h 20m 30s34d 10m 49s8.81.748Andromeda
03 Jun 201300h 20m 20s34d 57m 17s8.91.749Andromeda
04 Jun 201300h 20m 08s35d 43m 37s8.91.751Andromeda
05 Jun 201300h 19m 54s36d 29m 50s9.01.753Andromeda
06 Jun 201300h 19m 38s37d 15m 54s9.11.755Andromeda
07 Jun 201300h 19m 20s38d 01m 51s9.11.756Andromeda
08 Jun 201300h 19m 00s38d 47m 38s9.21.758Andromeda
09 Jun 201300h 18m 38s39d 33m 17s9.31.760Andromeda
10 Jun 201300h 18m 14s40d 18m 46s9.41.762Andromeda
11 Jun 201300h 17m 47s41d 04m 04s9.41.765Andromeda
12 Jun 201300h 17m 17s41d 49m 12s9.51.767Andromeda
13 Jun 201300h 16m 45s42d 34m 09s9.61.769Andromeda
14 Jun 201300h 16m 10s43d 18m 54s9.61.772Andromeda
15 Jun 201300h 15m 32s44d 03m 27s9.71.774Andromeda
16 Jun 201300h 14m 51s44d 47m 46s9.81.777Andromeda
17 Jun 201300h 14m 07s45d 31m 52s9.81.779Andromeda
18 Jun 201300h 13m 20s46d 15m 44s9.91.782Andromeda
19 Jun 201300h 12m 29s46d 59m 21s9.91.785Andromeda
20 Jun 201300h 11m 35s47d 42m 41s10.01.788Andromeda
21 Jun 201300h 10m 36s48d 25m 45s10.11.791Andromeda
22 Jun 201300h 09m 34s49d 08m 32s10.11.795Cassiopeia
23 Jun 201300h 08m 28s49d 51m 01s10.21.798Cassiopeia
24 Jun 201300h 07m 18s50d 33m 11s10.31.802Cassiopeia
25 Jun 201300h 06m 03s51d 15m 00s10.31.805Cassiopeia
26 Jun 201300h 04m 44s51d 56m 29s10.41.809Cassiopeia
27 Jun 201300h 03m 20s52d 37m 36s10.41.813Cassiopeia
28 Jun 201300h 01m 50s53d 18m 21s10.51.817Cassiopeia
29 Jun 201300h 00m 16s53d 58m 41s10.61.821Cassiopeia
30 Jun 201323h 58m 36s54d 38m 36s10.61.826Cassiopeia
01 Jul 201323h 56m 51s55d 18m 05s10.71.830Cassiopeia
02 Jul 201323h 54m 59s55d 57m 07s10.71.835Cassiopeia
03 Jul 201323h 53m 02s56d 35m 40s10.81.840Cassiopeia
04 Jul 201323h 50m 57s57d 13m 42s10.91.844Cassiopeia
05 Jul 201323h 48m 47s57d 51m 13s10.91.850Cassiopeia
06 Jul 201323h 46m 29s58d 28m 11s11.01.855Cassiopeia
07 Jul 201323h 44m 04s59d 04m 35s11.01.860Cassiopeia
08 Jul 201323h 41m 32s59d 40m 22s11.11.866Cassiopeia
09 Jul 201323h 38m 52s60d 15m 32s11.21.871Cassiopeia
10 Jul 201323h 36m 04s60d 50m 03s11.21.877Cassiopeia
11 Jul 201323h 33m 08s61d 23m 52s11.31.883Cassiopeia
12 Jul 201323h 30m 04s61d 56m 58s11.31.889Cassiopeia
13 Jul 201323h 26m 50s62d 29m 20s11.41.895Cassiopeia
14 Jul 201323h 23m 28s63d 00m 55s11.41.902Cassiopeia
15 Jul 201323h 19m 57s63d 31m 41s11.51.908Cassiopeia
16 Jul 201323h 16m 16s64d 01m 38s11.61.915Cepheus
17 Jul 201323h 12m 26s64d 30m 42s11.61.922Cepheus
18 Jul 201323h 08m 27s64d 58m 51s11.71.929Cepheus
19 Jul 201323h 04m 18s65d 26m 05s11.71.936Cepheus
20 Jul 201322h 59m 59s65d 52m 20s11.81.943Cepheus
21 Jul 201322h 55m 30s66d 17m 35s11.81.951Cepheus
22 Jul 201322h 50m 52s66d 41m 47s11.91.958Cepheus
23 Jul 201322h 46m 04s67d 04m 56s11.91.966Cepheus
24 Jul 201322h 41m 06s67d 26m 59s12.01.974Cepheus
25 Jul 201322h 35m 59s67d 47m 53s12.01.982Cepheus
26 Jul 201322h 30m 44s68d 07m 39s12.11.990Cepheus
27 Jul 201322h 25m 19s68d 26m 12s12.21.999Cepheus
28 Jul 201322h 19m 47s68d 43m 33s12.22.007Cepheus
29 Jul 201322h 14m 06s68d 59m 40s12.32.016Cepheus
30 Jul 201322h 08m 19s69d 14m 31s12.32.025Cepheus
31 Jul 201322h 02m 25s69d 28m 05s12.42.034Cepheus

See also

Comet Lemmon (C/2012 F6) now fading but remains visible through small telescopes in the June morning sky
Comet Lemmon (C/2012 F6) now visible in the morning sky from the northern hemisphere
Comet Lemmon (C/2012 F6) returns to the morning sky for observers located at southern hemisphere and tropical latitudes
Comet Lemmon (C/2012 F6) temporarily unobservable as it moves from evening to morning sky
Naked eye Comet Lemmon (C/2012 F6) moves past 47 Tuc and SMC
Comet Lemmon (C/2012 F6) now naked eye and continues to improve
Comet Lemmon (C/2012 F6) brightens faster than expected