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

19P/Borrelly reaches its brightest

Dominic Ford, Editor
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Comet 19P/Borrelly is forecast to reach its brightest. It will lie at a distance of 1.32 AU from the Sun, and at a distance of 1.23 AU from the Earth.

From Ashburn the 2021–2022 apparition of 19P/Borrelly 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.
20 Jan 2022 – 19P/Borrelly reaches its brightest
02 Feb 2022 – 19P/Borrelly at perihelion
30 Dec 2021CetusVisible from 18:05 until 20:20
Highest at 18:05, 32° above S horizon
01 Jan 2022CetusVisible from 18:06 until 20:26
Highest at 18:06, 33° above S horizon
03 Jan 2022CetusVisible from 18:08 until 20:30
Highest at 18:08, 35° above S horizon
05 Jan 2022CetusVisible from 18:09 until 20:35
Highest at 18:09, 36° above S horizon
07 Jan 2022CetusVisible from 18:11 until 20:39
Highest at 18:11, 37° above S horizon
09 Jan 2022CetusVisible from 18:13 until 20:43
Highest at 18:13, 38° above S horizon
11 Jan 2022CetusVisible from 18:15 until 20:46
Highest at 18:15, 39° above S horizon
13 Jan 2022CetusVisible from 18:16 until 20:49
Highest at 18:16, 40° above S horizon
15 Jan 2022CetusVisible from 18:18 until 20:52
Highest at 18:18, 41° above S horizon
17 Jan 2022CetusVisible from 18:20 until 20:55
Highest at 18:20, 42° above S horizon
19 Jan 2022CetusVisible from 18:22 until 20:58
Highest at 18:22, 43° above SW horizon
21 Jan 2022CetusVisible from 18:24 until 21:00
Highest at 18:24, 44° above SW horizon
23 Jan 2022CetusVisible from 18:26 until 21:02
Highest at 18:26, 45° above SW horizon
25 Jan 2022CetusVisible from 18:28 until 21:04
Highest at 18:28, 46° above SW horizon
27 Jan 2022CetusVisible from 18:30 until 21:07
Highest at 18:30, 47° above SW horizon
29 Jan 2022PiscesVisible from 18:32 until 21:09
Highest at 18:32, 47° above SW horizon
31 Jan 2022PiscesVisible from 18:34 until 21:10
Highest at 18:34, 48° above SW horizon
02 Feb 2022PiscesVisible from 18:37 until 21:12
Highest at 18:37, 48° above SW horizon
04 Feb 2022PiscesVisible from 18:39 until 21:14
Highest at 18:39, 49° above SW horizon
06 Feb 2022PiscesVisible from 18:41 until 21:16
Highest at 18:41, 49° above SW horizon
08 Feb 2022PiscesVisible from 18:43 until 21:17
Highest at 18:43, 50° above SW horizon

A more detailed table of 19P/Borrelly's position on each night is available here. A diagram of the orbit of 19P/Borrelly is available here.

On 20 January it will become visible around 18:23 (EST), 43° above your south-western horizon, as dusk fades to darkness. It will then sink towards the horizon, setting at 22:57.

Finder chart

The chart below shows the path of 19P/Borrelly 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 9 on 20 January 2022. 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 on 20 January 2022 will be:

Object Right Ascension Declination Constellation Magnitude
Comet 19P/Borrelly 00h58m50s 4°04'S Cetus 8.9

The coordinates are given in J2000.0.

The sky on 20 January 2022
Twilight ends
Twilight begins

18-day old moon
Waning Gibbous


18 days old

Rise Culm. Set
Mercury 07:32 12:41 17:51
Venus 05:52 11:00 16:09
Moon 18:53 02:11 09:20
Mars 05:16 09:56 14:36
Jupiter 09:08 14:35 20:03
Saturn 08:11 13:15 18:19
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 27 Dec 2021.

Image credit

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






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