Comet 15P/Finlay will make its closest approach to the Earth on 5 August, at a distance of of 0.26 AU.
From Cambridge on the day of perigee it will be visible in the dawn sky, rising at 00:52 (EDT) and reaching an altitude of 32° above the south-eastern horizon before fading from view as dawn breaks at around 04:23.
The events that comprise the 1988 apparition of 15P/Finlay are as follows:
| Date | Event |
| 05 Aug 1988 | Comet 15P/Finlay passes perigee |
| 15 Aug 1988 | Comet 15P/Finlay reaches peak brightness |
| 03 Sep 1988 | Comet 15P/Finlay passes perihelion |
The table below lists the times when 15P/Finlay will be visible from Cambridge day-by-day through its apparition:
| Date | Constellation | Comet visibility |
| 15 Jul 1988 | Sculptor | Not observable |
| 17 Jul 1988 | Sculptor | Not observable |
| 19 Jul 1988 | Sculptor | Visible from 03:47 until 04:01 Highest at 04:01, 21° above S horizon |
| 21 Jul 1988 | Cetus | Visible from 03:33 until 04:03 Highest at 04:03, 22° above S horizon |
| 23 Jul 1988 | Cetus | Visible from 03:22 until 04:06 Highest at 04:06, 23° above S horizon |
| 25 Jul 1988 | Cetus | Visible from 03:13 until 04:08 Highest at 04:08, 24° above SE horizon |
| 27 Jul 1988 | Cetus | Visible from 03:05 until 04:11 Highest at 04:11, 25° above SE horizon |
| 29 Jul 1988 | Cetus | Visible from 02:58 until 04:14 Highest at 04:14, 27° above SE horizon |
| 31 Jul 1988 | Cetus | Visible from 02:51 until 04:16 Highest at 04:16, 28° above SE horizon |
| 02 Aug 1988 | Cetus | Visible from 02:46 until 04:19 Highest at 04:19, 30° above SE horizon |
| 04 Aug 1988 | Cetus | Visible from 02:41 until 04:22 Highest at 04:22, 31° above SE horizon |
| 06 Aug 1988 | Cetus | Visible from 02:36 until 04:25 Highest at 04:25, 33° above SE horizon |
| 08 Aug 1988 | Eridanus | Visible from 02:33 until 04:28 Highest at 04:28, 35° above SE horizon |
| 10 Aug 1988 | Eridanus | Visible from 02:29 until 04:30 Highest at 04:30, 36° above SE horizon |
| 12 Aug 1988 | Taurus | Visible from 02:26 until 04:33 Highest at 04:33, 38° above SE horizon |
| 14 Aug 1988 | Taurus | Visible from 02:23 until 04:36 Highest at 04:36, 39° above SE horizon |
| 16 Aug 1988 | Taurus | Visible from 02:20 until 04:38 Highest at 04:38, 41° above SE horizon |
| 18 Aug 1988 | Taurus | Visible from 02:18 until 04:41 Highest at 04:41, 42° above SE horizon |
| 20 Aug 1988 | Taurus | Visible from 02:15 until 04:44 Highest at 04:44, 44° above SE horizon |
| 22 Aug 1988 | Taurus | Visible from 02:13 until 04:47 Highest at 04:47, 45° above SE horizon |
| 24 Aug 1988 | Taurus | Visible from 02:11 until 04:49 Highest at 04:49, 46° above SE horizon |
A more detailed table of 15P/Finlay's position on each night is available here. A diagram of the orbit of 15P/Finlay is available here.
Finder chart
The chart below shows the path of 15P/Finlay 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 15P/Finlay is currently available.
The comet's position at perigee will be:
| Object | Right Ascension | Declination | Constellation | Magnitude |
| Comet 15P/Finlay | 02h41m40s | 6°59'S | Cetus | 5.6 |
The coordinates are given in J2000.0.
The sky on 4 Apr 2025
| The sky on 4 April 2025 | ||||||||||||||||||||||||||||||||||
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48% 6 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.