There has been much written in 2013 about Comet ISON with early thoughts pointing towards a potential "Comet of the Century"; a dazzling sight, as bright as the Moon and visible in daylight. Now it's more than likely that ISON will fall well short of this mark but may not totally disappoint.
Comets are unpredictable and hopes for ISON have gradually eroded over the last few months as it failed to brighten as quickly as hoped. However, as this ball of "ice and dirt" hurls towards the Sun it should brighten enough to be visible with at least a pair of binoculars. There is a good chance it may be naked eye object in the early morning sky, from about November 15th until at least November 21st. With the possibility that it suddenly could ignite or equally disintegrate as it approaches perihelion (Nov. 28th), we're in for an exciting few days.
The best location to observe ISON is from the Northern Hemisphere. It will be observable in the early morning sky towards the east throughout the brightening period. For example, from 52N (e.g. London, England), ISON will be 11 degrees above the east-southeastern horizon 75 minutes before sunrise on November 19th. Hugging the eastern horizon at this time is Mercury (mag. -0.7) and just to the northwest of ISON is blue-white Spica (mag +1.0). At predicted magnitude +6.1, ISON is much fainter than Mercury or Spica but should be visible with binoculars. With a small amount luck, it may be brighter than this and visible to the naked eye.
For observers in the Southern Hemisphere, ISON is also visible, appearing low down above the eastern horizon as it brightens.
The finder chart below shows the path of ISON in Virgo from November 10th to November 21st. During this time it brightens from magnitude +8.0 to +5.6.
Comet ISON Finder Chart from November 10 to November 21, 2013 - pdf format
Comet ISON (C/2012 S1) Data (at epoch February 28, 2013)
| Name | C/2012 S1 (ISON) |
|---|---|
| Type | Comet |
| Classification | Hyperbolic Comet |
| Discoverer | Vitali Nevski and Artyom Novichonok using the ISON group of telescopes |
| Discovery date | September 21, 2012 |
| Aphelion (AU) | unknown |
| Perihelion (AU) | 0.01249 |
| Eccentricity | 1.000005 |
| Orbital period (years) | unknown |
| Inclination (degrees) | 61.981 |
| Longitude of ascending node (degrees) | 295.716 |
| Perihelion | November 28th, 2013 |
| Notes | Sungrazing comet |
Comet ISON (C/2012 S1) Data Table
| Date | Right Ascension | Declination | Estimated Magnitude | Distance from Earth (AU) | Constellation |
|---|---|---|---|---|---|
| 07 Nov 2013 | 11h 47m 05s | 01d 46m 54s | 8.5 | 1.072 | Virgo |
| 08 Nov 2013 | 11h 53m 53s | 00d 52m 22s | 8.3 | 1.047 | Virgo |
| 09 Nov 2013 | 12h 01m 02s | -00d 04m 59s | 8.1 | 1.024 | Virgo |
| 10 Nov 2013 | 12h 08m 33s | -01d 05m 14s | 8.0 | 1.002 | Virgo |
| 11 Nov 2013 | 12h 16m 28s | -02d 08m 26s | 7.8 | 0.980 | Virgo |
| 12 Nov 2013 | 12h 24m 48s | -03d 14m 38s | 7.6 | 0.960 | Virgo |
| 13 Nov 2013 | 12h 33m 35s | -04d 23m 48s | 7.4 | 0.941 | Virgo |
| 14 Nov 2013 | 12h 42m 50s | -05d 35m 52s | 7.2 | 0.924 | Virgo |
| 15 Nov 2013 | 12h 52m 34s | -06d 50m 42s | 7.0 | 0.908 | Virgo |
| 16 Nov 2013 | 13h 02m 50s | -08d 08m 02s | 6.8 | 0.894 | Virgo |
| 17 Nov 2013 | 13h 13m 38s | -09d 27m 35s | 6.6 | 0.881 | Virgo |
| 18 Nov 2013 | 13h 25m 00s | -10d 48m 53s | 6.4 | 0.871 | Virgo |
| 19 Nov 2013 | 13h 36m 57s | -12d 11m 24s | 6.1 | 0.864 | Virgo |
| 20 Nov 2013 | 13h 49m 29s | -13d 34m 26s | 5.8 | 0.858 | Virgo |
| 21 Nov 2013 | 14h 02m 36s | -14d 57m 12s | 5.6 | 0.856 | Virgo |
| 22 Nov 2013 | 14h 16m 21s | -16d 18m 46s | 5.2 | 0.857 | Virgo |
| 23 Nov 2013 | 14h 30m 43s | -17d 38m 06s | 4.9 | 0.861 | Libra |
| 24 Nov 2013 | 14h 45m 44s | -18d 54m 03s | 4.4 | 0.869 | Libra |
| 25 Nov 2013 | 15h 01m 29s | -20d 05m 16s | 3.9 | 0.882 | Libra |
| 26 Nov 2013 | 15h 18m 06s | -21d 10m 03s | 3.2 | 0.900 | Libra |
| 27 Nov 2013 | 15h 36m 00s | -22d 05m 35s | 2.1 | 0.924 | Libra |
| 28 Nov 2013 | 15h 56m 31s | -22d 43m 30s | 0.1 | 0.960 | Scorpius |
| 29 Nov 2013 | 16h 23m 17s | -19d 52m 17s | -3.1 | 0.976 | Scorpius |
| 30 Nov 2013 | 16h 21m 22s | -16d 20m 14s | 1.2 | 0.912 | Scorpius |
| 01 Dec 2013 | 16h 19m 11s | -13d 58m 52s | 2.6 | 0.868 | Scorpius |
| 02 Dec 2013 | 16h 17m 23s | -11d 55m 49s | 3.4 | 0.831 | Scorpius |
| 03 Dec 2013 | 16h 15m 54s | -10d 00m 41s | 3.9 | 0.798 | Scorpius |
| 04 Dec 2013 | 16h 14m 39s | -08d 09m 09s | 4.4 | 0.768 | Ophiuchus |
| 05 Dec 2013 | 16h 13m 36s | -06d 18m 51s | 4.7 | 0.740 | Ophiuchus |
| 06 Dec 2013 | 16h 12m 44s | -04d 28m 14s | 5.0 | 0.714 | Ophiuchus |
| 07 Dec 2013 | 16h 12m 02s | -02d 36m 10s | 5.2 | 0.690 | Serpens Caput |
| 08 Dec 2013 | 16h 11m 27s | 00d 41m 45s | 5.4 | 0.667 | Serpens Caput |
| 09 Dec 2013 | 16h 11m 00s | 01d 15m 45s | 5.6 | 0.644 | Serpens Caput |
| 10 Dec 2013 | 16h 10m 41s | 03d 17m 02s | 5.7 | 0.623 | Serpens Caput |
| 11 Dec 2013 | 16h 10m 27s | 05d 22m 41s | 5.9 | 0.603 | Serpens Caput |
| 12 Dec 2013 | 16h 10m 20s | 07d 33m 18s | 6.0 | 0.584 | Serpens Caput |
| 13 Dec 2013 | 16h 10m 19s | 09d 49m 24s | 6.1 | 0.566 | Serpens Caput |
| 14 Dec 2013 | 16h 10m 24s | 12d 11m 29s | 6.2 | 0.549 | Serpens Caput |
| 15 Dec 2013 | 16h 10m 34s | 14d 39m 59s | 6.3 | 0.532 | Serpens Caput |
| 16 Dec 2013 | 16h 10m 51s | 17d 15m 19s | 6.3 | 0.517 | Hercules |
| 17 Dec 2013 | 16h 11m 13s | 19d 57m 46s | 6.4 | 0.503 | Hercules |
| 18 Dec 2013 | 16h 11m 41s | 22d 47m 33s | 6.5 | 0.489 | Hercules |
| 19 Dec 2013 | 16h 12m 16s | 25d 44m 46s | 6.5 | 0.477 | Corona Borealis |
| 20 Dec 2013 | 16h 12m 58s | 28d 49m 21s | 6.6 | 0.466 | Corona Borealis |
| 21 Dec 2013 | 16h 13m 47s | 32d 01m 04s | 6.7 | 0.457 | Corona Borealis |
| 22 Dec 2013 | 16h 14m 44s | 35d 19m 30s | 6.7 | 0.448 | Corona Borealis |
| 23 Dec 2013 | 16h 15m 51s | 38d 43m 59s | 6.8 | 0.442 | Corona Borealis |
| 24 Dec 2013 | 16h 17m 07s | 42d 13m 39s | 6.9 | 0.436 | Hercules |
| 25 Dec 2013 | 16h 18m 36s | 45d 47m 25s | 6.9 | 0.432 | Hercules |
| 26 Dec 2013 | 16h 20m 19s | 49d 24m 02s | 7.0 | 0.430 | Hercules |
| 27 Dec 2013 | 16h 22m 19s | 53d 02m 04s | 7.1 | 0.429 | Draco |
| 28 Dec 2013 | 16h 24m 41s | 56d 40m 01s | 7.2 | 0.430 | Draco |
| 29 Dec 2013 | 16h 27m 31s | 60d 16m 21s | 7.3 | 0.433 | Draco |
| 30 Dec 2013 | 16h 30m 57s | 63d 49m 32s | 7.4 | 0.437 | Draco |
| 31 Dec 2013 | 16h 35m 13s | 67d 18m 09s | 7.5 | 0.442 | Draco |
See also
Crunch time approaches for Comet ISON (C/2012 S1)
Comet ISON (C/2012 S1) brightens as it nears Mars fly-by