Comet C/2004 H6 (SWAN) is forecast to reach the brightest point in its 2004 apparition on 3 May. At that time, it will lie at a distance of 0.79 AU from the Sun, and at a distance of 1.45 AU from the Earth.
From Cambridge on 3 May it will not be observable – it will reach its highest point in the sky during daytime and will be 27° below the horizon at dusk.
The events that comprise the 2004 apparition of C/2004 H6 (SWAN) are as follows:
| Date | Event |
| 03 May 2004 | Comet C/2004 H6 (SWAN) reaches peak brightness |
| 04 May 2004 | Comet C/2004 H6 (SWAN) passes perihelion |
The table below lists the times when C/2004 H6 (SWAN) will be visible from Cambridge day-by-day through its apparition:
| Date | Constellation | Comet visibility |
| 12 Apr 2004 | Eridanus | Not observable |
| 14 Apr 2004 | Eridanus | Not observable |
| 16 Apr 2004 | Eridanus | Not observable |
| 18 Apr 2004 | Eridanus | Not observable |
| 20 Apr 2004 | Eridanus | Not observable |
| 22 Apr 2004 | Eridanus | Not observable |
| 24 Apr 2004 | Eridanus | Not observable |
| 26 Apr 2004 | Eridanus | Not observable |
| 28 Apr 2004 | Eridanus | Not observable |
| 30 Apr 2004 | Eridanus | Not observable |
| 02 May 2004 | Eridanus | Not observable |
| 04 May 2004 | Eridanus | Not observable |
| 06 May 2004 | Eridanus | Not observable |
| 08 May 2004 | Eridanus | Not observable |
| 10 May 2004 | Eridanus | Not observable |
| 12 May 2004 | Eridanus | Not observable |
| 14 May 2004 | Eridanus | Not observable |
| 16 May 2004 | Eridanus | Not observable |
| 18 May 2004 | Eridanus | Not observable |
| 20 May 2004 | Eridanus | Not observable |
| 22 May 2004 | Eridanus | Not observable |
A more detailed table of C/2004 H6 (SWAN)'s position on each night is available here. A diagram of the orbit of C/2004 H6 (SWAN) is available here.
Finder chart
The chart below shows the path of C/2004 H6 (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/2004 H6 (SWAN) is currently available.
The comet's position on 3 May 2004 will be:
| Object | Right Ascension | Declination | Constellation | Magnitude |
| Comet C/2004 H6 (SWAN) | 03h28m50s | 13°28'S | Eridanus | 6.9 |
The coordinates are given in J2000.0.
The sky on 14 Mar 2025
| The sky on 14 March 2025 | ||||||||||||||||||||||||||||||||||
|
99% 14 days old |
All times shown in EDT.
|
|||||||||||||||||||||||||||||||||
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.