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

Comet C/2020 M3 (ATLAS) reaches peak brightness

Dominic Ford, Editor
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Comet C/2020 M3 (ATLAS) is forecast to reach the brightest point in its 2020 apparition on 9 November. At that time, it will lie at a distance of 1.29 AU from the Sun, and at a distance of 0.36 AU from the Earth.

From Ashburn on 9 November it will be visible in the morning sky, becoming accessible around 22:18, when it reaches an altitude of 21° above your eastern horizon. It will then reach its highest point in the sky at 02:14, 48° above your southern horizon. It will be lost to dawn twilight around 05:38, 27° above your south-western horizon.

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The events that comprise the 2020 apparition of C/2020 M3 (ATLAS) are as follows:

Date Event
26 Oct 2020Comet C/2020 M3 (ATLAS) passes perihelion
09 Nov 2020Comet C/2020 M3 (ATLAS) reaches peak brightness
14 Nov 2020Comet C/2020 M3 (ATLAS) passes perigee

The table below lists the times when C/2020 M3 (ATLAS) will be visible from Ashburn day-by-day through its apparition:

Date Constellation Comet visibility
19 Oct 2020LepusVisible from 02:14 until 06:14
Highest at 04:14, 28° above S horizon
21 Oct 2020LepusVisible from 01:56 until 06:20
Highest at 04:09, 30° above S horizon
23 Oct 2020LepusVisible from 01:39 until 06:22
Highest at 04:04, 31° above S horizon
25 Oct 2020LepusVisible from 01:21 until 06:24
Highest at 03:59, 33° above S horizon
27 Oct 2020LepusVisible from 01:04 until 06:26
Highest at 03:54, 35° above S horizon
29 Oct 2020LepusVisible from 00:48 until 06:27
Highest at 03:48, 37° above S horizon
31 Oct 2020LepusVisible from 00:31 until 06:29
Highest at 03:43, 39° above S horizon
02 Nov 2020OrionVisible from 23:14 until 05:31
Highest at 02:37, 41° above S horizon
04 Nov 2020OrionVisible from 22:57 until 05:33
Highest at 02:31, 43° above S horizon
06 Nov 2020OrionVisible from 22:41 until 05:35
Highest at 02:24, 46° above S horizon
08 Nov 2020OrionVisible from 22:24 until 05:37
Highest at 02:18, 48° above S horizon
10 Nov 2020OrionVisible from 22:08 until 05:39
Highest at 02:11, 51° above S horizon
12 Nov 2020OrionVisible from 21:51 until 05:41
Highest at 02:04, 53° above S horizon
14 Nov 2020OrionVisible from 21:35 until 05:43
Highest at 01:56, 56° above S horizon
16 Nov 2020OrionVisible from 21:18 until 05:45
Highest at 01:49, 58° above S horizon
18 Nov 2020OrionVisible from 21:02 until 05:47
Highest at 01:41, 61° above S horizon
20 Nov 2020OrionVisible from 20:46 until 05:49
Highest at 01:33, 64° above S horizon
22 Nov 2020OrionVisible from 20:30 until 05:51
Highest at 01:25, 66° above S horizon
24 Nov 2020TaurusVisible from 20:14 until 05:53
Highest at 01:17, 69° above S horizon
26 Nov 2020TaurusVisible from 19:58 until 05:55
Highest at 01:09, 71° above S horizon
28 Nov 2020TaurusVisible from 19:42 until 05:57
Highest at 01:00, 74° above S horizon

A more detailed table of C/2020 M3 (ATLAS)'s position on each night is available here. A diagram of the orbit of C/2020 M3 (ATLAS) is available here.

Finder chart

The chart below shows the path of C/2020 M3 (ATLAS) 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 C/2020 M3 (ATLAS) is currently available.

The comet's position on 9 November 2020 will be:

Object Right Ascension Declination Constellation Magnitude
Comet C/2020 M3 (ATLAS) 05h20m10s 2°23'S Orion 8.2

The coordinates are given in J2000.0.

The sky on 9 Nov 2020

The sky on 9 November 2020
Twilight ends
Twilight begins

24-day old moon
Waning Crescent


24 days old

Rise Culm. Set
Mercury 05:08 10:42 16:16
Venus 04:02 09:51 15:40
Moon 23:48 07:04 14:10
Mars 15:29 21:48 04:07
Jupiter 11:41 16:27 21:14
Saturn 11:56 16:45 21:35
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 Apr 2024.

Image credit

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





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