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

15P/Finlay at perihelion

Dominic Ford, Editor
From the Comets feed

Objects: 15P/Finlay
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Comet 15P/Finlay will make its closest approach to the Sun, at a distance of 1.00 AU.

From Fairfield the 2021 apparition of 15P/Finlay will progress as follows:

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18 Jun 2021 – 15P/Finlay at perigee
07 Jul 2021 – 15P/Finlay reaches its brightest
13 Jul 2021 – 15P/Finlay at perihelion
22 Jun 2021CetusNot observable
24 Jun 2021CetusNot observable
26 Jun 2021AriesNot observable
28 Jun 2021AriesNot observable
30 Jun 2021AriesNot observable
02 Jul 2021AriesNot observable
04 Jul 2021AriesNot observable
06 Jul 2021AriesNot observable
08 Jul 2021AriesNot observable
10 Jul 2021TaurusNot observable
12 Jul 2021TaurusVisible from 04:03 until 04:06
Highest at 04:06, 22° above E horizon
14 Jul 2021TaurusVisible from 04:01 until 04:08
Highest at 04:08, 23° above E horizon
16 Jul 2021TaurusVisible from 04:00 until 04:10
Highest at 04:10, 24° above E horizon
18 Jul 2021TaurusVisible from 03:59 until 04:12
Highest at 04:12, 24° above E horizon
20 Jul 2021TaurusVisible from 03:57 until 04:15
Highest at 04:15, 25° above E horizon
22 Jul 2021TaurusVisible from 03:56 until 04:17
Highest at 04:17, 26° above E horizon
24 Jul 2021TaurusVisible from 03:55 until 04:19
Highest at 04:19, 26° above E horizon
26 Jul 2021TaurusVisible from 03:54 until 04:22
Highest at 04:22, 27° above E horizon
28 Jul 2021TaurusVisible from 03:53 until 04:24
Highest at 04:24, 28° above E horizon
30 Jul 2021TaurusVisible from 03:52 until 04:27
Highest at 04:27, 28° above E horizon
01 Aug 2021TaurusVisible from 03:50 until 04:29
Highest at 04:29, 29° 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.

At the moment of perihelion it will be visible in the dawn sky, rising at 01:56 (EST) – 3 hours and 33 minutes before the Sun – and reaching an altitude of 23° above the eastern horizon before fading from view as dawn breaks around 04:07.

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.

Based on the magnitude parameters published for this comet by the BAA Comet Section, we estimate that it may be around mag 8 at perihelion. This estimate is based on observations that the BAA has received from amateur astronomers, assuming that its current level of activity will remain constant.

This comet is not expected to be visible to the naked eye, but might be visible through bird-watching binoculars.

The comet's position at perihelion will be:

Object Right Ascension Declination Constellation Magnitude
Comet 15P/Finlay 03h40m00s 18°18'N Taurus 8.4

The coordinates are given in J2000.0.

The sky on 13 July 2021
Twilight ends
Twilight begins

3-day old moon
Waxing Crescent


3 days old

Rise Culm. Set
Mercury 04:09 11:36 19:03
Venus 07:52 14:55 21:59
Moon 08:53 16:04 23:03
Mars 07:53 14:55 21:56
Jupiter 22:21 03:41 09:01
Saturn 21:26 02:23 07:20
All times shown in EDT.


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 27 Dec 2021.

Image credit

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






Color scheme