Comet 78P/Gehrels will make its closest approach to the Sun on 28 October, at a distance of 2.00 AU.
From Fairfield on the day of perihelion it will be visible in the morning sky, becoming accessible around 20:44, when it reaches an altitude of 21° above your eastern horizon. It will then reach its highest point in the sky at 01:39, 64° above your southern horizon. It will be lost to dawn twilight around 06:12, 26° above your western horizon.
The events that comprise the 2004 apparition of 78P/Gehrels are as follows:
| Date | Event |
| 28 Oct 2004 | Comet 78P/Gehrels passes perihelion |
The table below lists the times when 78P/Gehrels will be visible from Fairfield day-by-day through its apparition:
| Date | Constellation | Comet visibility |
| 07 Oct 2004 | Aries | Visible from 22:00 until 05:50 Highest at 03:03, 66° above S horizon |
| 09 Oct 2004 | Aries | Visible from 21:53 until 05:52 Highest at 02:55, 66° above S horizon |
| 11 Oct 2004 | Aries | Visible from 21:45 until 05:54 Highest at 02:47, 66° above S horizon |
| 13 Oct 2004 | Aries | Visible from 21:38 until 05:56 Highest at 02:39, 66° above S horizon |
| 15 Oct 2004 | Aries | Visible from 21:31 until 05:58 Highest at 02:31, 66° above S horizon |
| 17 Oct 2004 | Aries | Visible from 21:23 until 06:00 Highest at 02:23, 65° above S horizon |
| 19 Oct 2004 | Aries | Visible from 21:16 until 06:02 Highest at 02:15, 65° above S horizon |
| 21 Oct 2004 | Aries | Visible from 21:08 until 06:04 Highest at 02:07, 65° above S horizon |
| 23 Oct 2004 | Aries | Visible from 21:01 until 06:07 Highest at 01:58, 65° above S horizon |
| 25 Oct 2004 | Aries | Visible from 20:53 until 06:09 Highest at 01:50, 64° above S horizon |
| 27 Oct 2004 | Aries | Visible from 20:45 until 06:11 Highest at 01:41, 64° above S horizon |
| 29 Oct 2004 | Aries | Visible from 20:37 until 06:13 Highest at 01:32, 64° above S horizon |
| 31 Oct 2004 | Aries | Visible from 20:29 until 05:15 Highest at 01:24, 64° above S horizon |
| 02 Nov 2004 | Aries | Visible from 19:21 until 05:08 Highest at 00:15, 63° above S horizon |
| 04 Nov 2004 | Aries | Visible from 19:13 until 04:58 Highest at 00:06, 63° above S horizon |
| 06 Nov 2004 | Aries | Visible from 19:01 until 04:45 Highest at 23:53, 63° above S horizon |
| 08 Nov 2004 | Aries | Visible from 18:53 until 04:35 Highest at 23:44, 63° above S horizon |
| 10 Nov 2004 | Aries | Visible from 18:45 until 04:25 Highest at 23:35, 62° above S horizon |
| 12 Nov 2004 | Aries | Visible from 18:37 until 04:16 Highest at 23:26, 62° above S horizon |
| 14 Nov 2004 | Aries | Visible from 18:29 until 04:06 Highest at 23:18, 62° above S horizon |
| 16 Nov 2004 | Aries | Visible from 18:21 until 03:56 Highest at 23:09, 62° above S horizon |
A more detailed table of 78P/Gehrels's position on each night is available here. A diagram of the orbit of 78P/Gehrels is available here.
Finder chart
The chart below shows the path of 78P/Gehrels 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 78P/Gehrels is currently available.
The comet's position at perihelion will be:
| Object | Right Ascension | Declination | Constellation | Magnitude |
| Comet 78P/Gehrels | 03h14m20s | 15°17'N | Aries | 9.8 |
The coordinates are given in J2000.0.
The sky on 23 Nov 2024
| The sky on 23 November 2024 | ||||||||||||||||||||||||||||||||||
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37% 22 days old |
All times shown in EST.
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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 13 Oct 2024.
Image credit
© Andy Roberts 1997. Pictured comet is C/1995 O1 Hale-Bopp.