Comet C/2012 S1 (ISON) will make its closest approach to the Sun on 28 November, at a distance of 0.02 AU.
From South El Monte on the day of perihelion it will not be readily observable since it will be very close to the Sun, at a separation of only 1° from it.
The events that comprise the 2013–2014 apparition of C/2012 S1 (ISON) are as follows:
| Date | Event |
| 28 Nov 2013 | Comet C/2012 S1 (ISON) passes perihelion |
| 26 Dec 2013 | Comet C/2012 S1 (ISON) passes perigee |
The table below lists the times when C/2012 S1 (ISON) will be visible from South El Monte day-by-day through its apparition:
| Date | Constellation | Comet visibility |
| 07 Nov 2013 | Virgo | Visible from 04:07 until 05:14 Highest at 05:14, 33° above SE horizon |
| 09 Nov 2013 | Virgo | Visible from 04:16 until 05:16 Highest at 05:16, 31° above SE horizon |
| 11 Nov 2013 | Virgo | Visible from 04:28 until 05:18 Highest at 05:18, 28° above SE horizon |
| 13 Nov 2013 | Virgo | Visible from 04:42 until 05:19 Highest at 05:19, 25° above SE horizon |
| 15 Nov 2013 | Virgo | Visible from 04:59 until 05:21 Highest at 05:21, 21° above SE horizon |
| 17 Nov 2013 | Virgo | Visible from 05:18 until 05:24 Highest at 05:24, 18° above SE horizon |
| 19 Nov 2013 | Virgo | Not observable |
| 21 Nov 2013 | Virgo | Not observable |
| 23 Nov 2013 | Libra | Not observable |
| 25 Nov 2013 | Libra | Not observable |
| 27 Nov 2013 | Scorpius | Not observable |
| 29 Nov 2013 | Scorpius | Not observable |
| 01 Dec 2013 | Scorpius | Not observable |
| 03 Dec 2013 | Scorpius | Not observable |
| 05 Dec 2013 | Ophiuchus | Not observable |
| 07 Dec 2013 | Serpens Caput | Not observable |
| 09 Dec 2013 | Serpens Caput | Not observable |
| 11 Dec 2013 | Serpens Caput | Visible from 05:34 until 05:49 Highest at 05:49, 18° above E horizon |
| 13 Dec 2013 | Serpens Caput | Visible from 05:15 until 05:49 Highest at 05:49, 23° above E horizon |
| 15 Dec 2013 | Hercules | Visible from 04:56 until 05:49 Highest at 05:49, 27° above E horizon |
| 17 Dec 2013 | Hercules | Visible from 04:35 until 05:50 Highest at 05:50, 31° above E horizon |
A more detailed table of C/2012 S1 (ISON)'s position on each night is available here. A diagram of the orbit of C/2012 S1 (ISON) is available here.
Finder chart
The chart below shows the path of C/2012 S1 (ISON) over the course of its apparition, as calculated from the orbital elements published by the Minor Planet Center (MPC). It is available for download, either on dark background, in PNG, PDF or SVG formats, or on a light background, in PNG, PDF or SVG formats. It was produced using StarCharter.
Comet brightnesses
Comets are intrinsically highly unpredictable objects, since their brightness depends on the scattering of sunlight from dust particles in the comet's coma and tail. This dust is continually streaming away from the comet's nucleus, and its density at any particular time is governed by the rate of sublimation of the ice in the comet's nucleus, as it is heated by the Sun's rays. It also depends on the amount of dust that is mixed in with that ice. This is very difficult to predict in advance, and can be highly variable even between successive apparitions of the same comet.
In consequence, while the future positions of comets are usually known with a high degree of confidence, their future brightnesses are not. For most comets, we do not publish any magnitude estimates at all. For the few comets where we do make estimates, we generally prefer the BAA's magnitude parameters to those published by the Minor Planet Center, since they are typically updated more often.
No estimate for the brightness of comet C/2012 S1 (ISON) is currently available.
The comet's position at perihelion will be:
| Object | Right Ascension | Declination | Constellation | Magnitude |
| Comet C/2012 S1 (ISON) | 16h15m00s | 22°19'S | Scorpius | -3.3 |
The coordinates are given in J2000.0.
The sky on 17 Dec 2025
| The sky on 17 December 2025 | ||||||||||||||||||||||||||||||||||
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4% 27 days old |
All times shown in PST.
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Warning
Never attempt to point a pair of binoculars or a telescope at an object close to the Sun. Doing so may result in immediate and permanent blindness.
Source
This event was automatically generated on the basis of orbital elements published by the Minor Planet Center (MPC) , and is updated whenever new elements become available. It was last updated on 15 Dec 2025.
Image credit
© Andy Roberts 1997. Pictured comet is C/1995 O1 Hale-Bopp.