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

2I/Borisov at perihelion

Dominic Ford, Editor
From the Comets feed

Objects: 2I/Borisov
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Comet 2I/Borisov will make its closest approach to the Sun, at a distance of 2.00 AU.

From Fairfield the 2019–2020 apparition of 2I/Borisov will progress as follows:

Begin typing the name of a town near to you, and then select the town from the list of options which appear below.
08 Dec 2019 – 2I/Borisov at perihelion
17 Nov 2019CraterVisible from 02:19 until 06:26
Highest at 06:26, 41° above S horizon
19 Nov 2019CraterVisible from 02:18 until 06:28
Highest at 06:28, 40° above S horizon
21 Nov 2019CraterVisible from 02:18 until 06:30
Highest at 06:30, 39° above S horizon
23 Nov 2019CraterVisible from 02:17 until 06:32
Highest at 06:32, 38° above S horizon
25 Nov 2019CraterVisible from 02:16 until 06:35
Highest at 06:35, 37° above S horizon
27 Nov 2019CraterVisible from 02:16 until 06:37
Highest at 06:37, 36° above S horizon
29 Nov 2019CraterVisible from 02:15 until 06:39
Highest at 06:39, 35° above S horizon
01 Dec 2019CraterVisible from 02:15 until 06:41
Highest at 06:35, 34° above S horizon
03 Dec 2019CraterVisible from 02:14 until 06:43
Highest at 06:30, 33° above S horizon
05 Dec 2019CraterVisible from 02:14 until 06:45
Highest at 06:25, 32° above S horizon
07 Dec 2019CraterVisible from 02:14 until 06:46
Highest at 06:19, 31° above S horizon
09 Dec 2019CraterVisible from 02:15 until 06:48
Highest at 06:14, 29° above S horizon
11 Dec 2019CraterVisible from 02:15 until 06:50
Highest at 06:08, 28° above S horizon
13 Dec 2019CraterVisible from 02:16 until 06:51
Highest at 06:03, 27° above S horizon
15 Dec 2019CraterVisible from 02:17 until 06:53
Highest at 05:57, 26° above S horizon
17 Dec 2019CraterVisible from 02:18 until 06:54
Highest at 05:52, 25° above S horizon
19 Dec 2019HydraVisible from 02:19 until 06:55
Highest at 05:46, 23° above S horizon
21 Dec 2019HydraVisible from 02:21 until 06:56
Highest at 05:40, 22° above S horizon
23 Dec 2019HydraVisible from 02:23 until 06:57
Highest at 05:34, 21° above S horizon
25 Dec 2019HydraVisible from 02:25 until 06:58
Highest at 05:28, 20° above S horizon
27 Dec 2019HydraVisible from 02:28 until 06:59
Highest at 05:22, 19° above S horizon

A more detailed table of 2I/Borisov's position on each night is available here. A diagram of the orbit of 2I/Borisov is available here.

At the moment of perihelion it will be visible in the dawn sky, rising at 01:21 (EST) and reaching an altitude of 30° above the southern horizon before fading from view as dawn breaks around 05:53.

Finder chart

The chart below shows the path of 2I/Borisov 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 16 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.

You will require a telescope to see this comet.

The comet's position at perihelion will be:

Object Right Ascension Declination Constellation Magnitude
Comet 2I/Borisov 11h29m50s -18°28' Crater 15.5

The coordinates are given in J2000.0.

The sky on 08 December 2019
Twilight ends
Twilight begins

12-day old moon
Waxing Gibbous


12 days old

Rise Culm. Set
Mercury 05:37 10:32 15:28
Venus 09:22 13:53 18:24
Moon 14:39 21:17 02:56
Mars 04:17 09:26 14:35
Jupiter 08:15 12:50 17:25
Saturn 09:24 14:05 18:45
All times shown in EST.


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 06 Dec 2020.

Image credit

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






Color scheme