Comet 15P/Finlay passes perigee

Dominic Ford, Editor
From the Comets feed


Objects: 15P/Finlay

Comet 15P/Finlay will make its closest approach to the Earth on 31 December, at a distance of of 1.11 AU.

From South El Monte on the day of perigee it will be visible in the evening sky, becoming accessible around 18:00 (PDT), 59° above your south-eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 18:55, 62° above your southern horizon. It will continue to be observable until around 23:25, 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
27 May 2021PiscesNot observable
29 May 2021PiscesNot observable
31 May 2021CetusNot observable
02 Jun 2021CetusNot observable
04 Jun 2021CetusNot observable
06 Jun 2021CetusNot observable
08 Jun 2021CetusNot observable
10 Jun 2021CetusNot observable
12 Jun 2021PiscesNot observable
14 Jun 2021PiscesNot observable
16 Jun 2021PiscesVisible from 04:25 until 04:26
Highest at 04:26, 22° above E horizon
18 Jun 2021PiscesVisible from 04:23 until 04:26
Highest at 04:26, 23° above E horizon
20 Jun 2021PiscesVisible from 04:21 until 04:26
Highest at 04:26, 23° above E horizon
22 Jun 2021CetusVisible from 04:19 until 04:27
Highest at 04:27, 23° above E horizon
24 Jun 2021CetusVisible from 04:18 until 04:27
Highest at 04:27, 24° above E horizon
26 Jun 2021AriesVisible from 04:16 until 04:28
Highest at 04:28, 24° above E horizon
28 Jun 2021AriesVisible from 04:15 until 04:29
Highest at 04:29, 25° above E horizon
30 Jun 2021AriesVisible from 04:14 until 04:30
Highest at 04:30, 25° above E horizon
02 Jul 2021AriesVisible from 04:12 until 04:31
Highest at 04:31, 26° above E horizon
04 Jul 2021AriesVisible from 04:11 until 04:32
Highest at 04:32, 26° above E horizon
06 Jul 2021AriesVisible from 04:10 until 04:33
Highest at 04:33, 27° 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 at perigee will be:

Object Right Ascension Declination Constellation Magnitude
Comet 15P/Finlay 01h44m50s 6°03'N Pisces 8.7

The coordinates are given in J2000.0.

The sky on 21 Oct 2025

The sky on 21 October 2025
Sunrise
06:59
Sunset
18:10
Twilight ends
19:34
Twilight begins
05:36


Waxing Crescent

0%

30 days old

Planets
Rise Culm. Set
Mercury 08:55 14:00 19:05
Venus 05:31 11:27 17:23
Moon 07:17 12:42 18:01
Mars 08:47 13:59 19:11
Jupiter 23:30 06:35 13:39
Saturn 16:45 22:37 04:29
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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