Comet C/2006 M4 (SWAN) will make its closest approach to the Earth on 25 October, at a distance of of 1.00 AU.
From Cambridge on the day of perigee it will become visible at around 18:55 (EDT), 38° above your western horizon, as dusk fades to darkness. It will then sink towards the horizon, setting at 23:11.
The events that comprise the 2006 apparition of C/2006 M4 (SWAN) are as follows:
| Date | Event |
| 29 Sep 2006 | Comet C/2006 M4 (SWAN) passes perihelion |
| 13 Oct 2006 | Comet C/2006 M4 (SWAN) reaches peak brightness |
| 25 Oct 2006 | Comet C/2006 M4 (SWAN) passes perigee |
The table below lists the times when C/2006 M4 (SWAN) will be visible from Cambridge day-by-day through its apparition:
| Date | Constellation | Comet visibility |
| 04 Oct 2006 | Canes Venatici | Not observable |
| 06 Oct 2006 | Canes Venatici | Not observable |
| 08 Oct 2006 | Canes Venatici | Not observable |
| 10 Oct 2006 | Canes Venatici | Visible from 19:17 until 19:19 Highest at 19:17, 17° above NW horizon |
| 12 Oct 2006 | Canes Venatici | Visible from 19:14 until 19:33 Highest at 19:14, 20° above NW horizon |
| 14 Oct 2006 | Canes Venatici | Visible from 19:11 until 19:47 Highest at 19:11, 22° above NW horizon |
| 16 Oct 2006 | Bootes | Visible from 19:08 until 20:01 Highest at 19:08, 25° above NW horizon |
| 18 Oct 2006 | Bootes | Visible from 19:05 until 20:14 Highest at 19:05, 28° above NW horizon |
| 20 Oct 2006 | Bootes | Visible from 19:02 until 20:27 Highest at 19:02, 31° above NW horizon |
| 22 Oct 2006 | Bootes | Visible from 18:59 until 20:39 Highest at 18:59, 34° above W horizon |
| 24 Oct 2006 | Corona Borealis | Visible from 18:56 until 20:50 Highest at 18:56, 36° above W horizon |
| 26 Oct 2006 | Corona Borealis | Visible from 18:53 until 20:58 Highest at 18:53, 39° above W horizon |
| 28 Oct 2006 | Hercules | Visible from 18:51 until 21:05 Highest at 18:51, 41° above W horizon |
| 30 Oct 2006 | Hercules | Visible from 17:48 until 20:10 Highest at 17:48, 43° above W horizon |
| 01 Nov 2006 | Hercules | Visible from 17:46 until 20:14 Highest at 17:46, 44° above W horizon |
| 03 Nov 2006 | Hercules | Visible from 17:44 until 20:15 Highest at 17:44, 46° above W horizon |
| 05 Nov 2006 | Hercules | Visible from 17:41 until 20:15 Highest at 17:41, 47° above W horizon |
| 07 Nov 2006 | Hercules | Visible from 17:39 until 20:14 Highest at 17:39, 47° above W horizon |
| 09 Nov 2006 | Hercules | Visible from 17:37 until 20:12 Highest at 17:37, 48° above W horizon |
| 11 Nov 2006 | Hercules | Visible from 17:36 until 20:09 Highest at 17:36, 47° above W horizon |
| 13 Nov 2006 | Hercules | Visible from 17:34 until 20:05 Highest at 17:34, 47° above W horizon |
A more detailed table of C/2006 M4 (SWAN)'s position on each night is available here. A diagram of the orbit of C/2006 M4 (SWAN) is available here.
Finder chart
The chart below shows the path of C/2006 M4 (SWAN) 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/2006 M4 (SWAN) is currently available.
The comet's position at perigee will be:
| Object | Right Ascension | Declination | Constellation | Magnitude |
| Comet C/2006 M4 (SWAN) | 15h57m30s | 35°12'N | 5.5 |
The coordinates are given in J2000.0.
The sky on 14 Mar 2025
| The sky on 14 March 2025 | ||||||||||||||||||||||||||||||||||
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99% 14 days old |
All times shown in EDT.
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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 23 Feb 2025.
Image credit
© Andy Roberts 1997. Pictured comet is C/1995 O1 Hale-Bopp.