Comet 15P/Finlay reaches peak brightness

Dominic Ford, Editor
From the Comets feed


Objects: 15P/Finlay

Comet 15P/Finlay is forecast to reach the brightest point in its 1969 apparition on 31 December. At that time, it will lie at a distance of 1.01 AU from the Sun, and at a distance of 0.55 AU from the Earth.

From South El Monte on 31 December it will be visible in the evening sky, becoming accessible around 18:00 (PDT), 43° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 21:08, 70° above your southern horizon. It will continue to be observable until around 02:00, when it sinks below 21° above your western horizon.

The events that comprise the 1969–1970 apparition of 15P/Finlay are as follows:

Date Event

The table below lists the times when 15P/Finlay will be visible from South El Monte day-by-day through its apparition:

Date Constellation Comet visibility
16 Jul 1988CetusVisible from 02:58 until 04:42
Highest at 04:42, 41° above SE horizon
18 Jul 1988CetusVisible from 02:56 until 04:44
Highest at 04:44, 42° above SE horizon
20 Jul 1988CetusVisible from 02:55 until 04:46
Highest at 04:46, 42° above SE horizon
22 Jul 1988CetusVisible from 02:54 until 04:48
Highest at 04:48, 43° above SE horizon
24 Jul 1988CetusVisible from 02:53 until 04:49
Highest at 04:49, 44° above SE horizon
26 Jul 1988CetusVisible from 02:52 until 04:51
Highest at 04:51, 45° above SE horizon
28 Jul 1988CetusVisible from 02:51 until 04:53
Highest at 04:53, 45° above SE horizon
30 Jul 1988CetusVisible from 02:50 until 04:55
Highest at 04:55, 46° above SE horizon
01 Aug 1988TaurusVisible from 02:49 until 04:57
Highest at 04:57, 46° above E horizon
03 Aug 1988TaurusVisible from 02:49 until 04:58
Highest at 04:58, 47° above E horizon
05 Aug 1988TaurusVisible from 02:48 until 05:00
Highest at 05:00, 48° above E horizon
07 Aug 1988TaurusVisible from 02:48 until 05:02
Highest at 05:02, 48° above E horizon
09 Aug 1988TaurusVisible from 02:47 until 05:04
Highest at 05:04, 49° above E horizon
11 Aug 1988TaurusVisible from 02:47 until 05:06
Highest at 05:06, 49° above E horizon
13 Aug 1988TaurusVisible from 02:47 until 05:08
Highest at 05:08, 50° above E horizon
15 Aug 1988TaurusVisible from 02:46 until 05:09
Highest at 05:09, 50° above E horizon
17 Aug 1988TaurusVisible from 02:46 until 05:11
Highest at 05:11, 51° above E horizon
19 Aug 1988TaurusVisible from 02:45 until 05:13
Highest at 05:13, 51° above E horizon
21 Aug 1988TaurusVisible from 02:45 until 05:15
Highest at 05:15, 52° above E horizon
23 Aug 1988TaurusVisible from 02:44 until 05:17
Highest at 05:17, 52° above E horizon
25 Aug 1988TaurusVisible from 02:44 until 05:18
Highest at 05:18, 53° above E 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 on 1 January 1970 will be:

Object Right Ascension Declination Constellation Magnitude
Comet 15P/Finlay 03h57m30s 14°27'N Taurus 6.9

The coordinates are given in J2000.0.

The sky on 22 Oct 2025

The sky on 22 October 2025
Sunrise
07:00
Sunset
18:09
Twilight ends
19:33
Twilight begins
05:36


Waxing Crescent

3%

1 day old

Planets
Rise Culm. Set
Mercury 08:57 14:01 19:05
Venus 05:33 11:28 17:23
Moon 08:15 13:26 18:30
Mars 08:46 13:58 19:09
Jupiter 23:27 06:31 13:35
Saturn 16:41 22:33 04:25
All times shown in PDT.

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 29 Sep 2025.

Image credit

© Andy Roberts 1997. Pictured comet is C/1995 O1 Hale-Bopp.

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