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

Comet C/2020 M3 (ATLAS) passes perihelion

Dominic Ford, Editor
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Comet C/2020 M3 (ATLAS) will make its closest approach to the Sun on 25 October, at a distance of 1.27 AU.

From Ashburn on the day of perihelion it will be visible in the morning sky, becoming accessible around 01:25, when it reaches an altitude of 21° above your south-eastern horizon. It will then reach its highest point in the sky at 03:59, 32° above your southern horizon. It will be lost to dawn twilight around 06:24, 23° 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
25 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
04 Oct 2020EridanusNot observable
06 Oct 2020EridanusNot observable
08 Oct 2020EridanusNot observable
10 Oct 2020EridanusVisible from 04:00 until 05:07
Highest at 04:34, 22° above S horizon
12 Oct 2020EridanusVisible from 03:29 until 05:31
Highest at 04:30, 24° above S horizon
14 Oct 2020EridanusVisible from 03:05 until 05:46
Highest at 04:26, 25° above S horizon
16 Oct 2020EridanusVisible from 02:44 until 05:59
Highest at 04:21, 26° above S horizon
18 Oct 2020LepusVisible from 02:25 until 06:09
Highest at 04:17, 27° above S horizon
20 Oct 2020LepusVisible from 02:06 until 06:18
Highest at 04:12, 29° above S horizon
22 Oct 2020LepusVisible from 01:49 until 06:21
Highest at 04:08, 30° above S horizon
24 Oct 2020LepusVisible from 01:31 until 06:23
Highest at 04:03, 32° above S horizon
26 Oct 2020LepusVisible from 01:14 until 06:25
Highest at 03:57, 34° above S horizon
28 Oct 2020LepusVisible from 00:57 until 06:27
Highest at 03:52, 36° above S horizon
30 Oct 2020LepusVisible from 00:40 until 06:28
Highest at 03:46, 38° above S horizon
01 Nov 2020LepusVisible from 00:23 until 05:30
Highest at 02:40, 40° above S horizon
03 Nov 2020OrionVisible from 23:07 until 05:32
Highest at 02:34, 42° above S horizon
05 Nov 2020OrionVisible from 22:50 until 05:34
Highest at 02:28, 44° above S horizon
07 Nov 2020OrionVisible from 22:33 until 05:36
Highest at 02:22, 47° above S horizon
09 Nov 2020OrionVisible from 22:17 until 05:38
Highest at 02:15, 49° above S horizon
11 Nov 2020OrionVisible from 22:00 until 05:40
Highest at 02:08, 52° above S horizon
13 Nov 2020OrionVisible from 21:44 until 05:42
Highest at 02:01, 54° 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 at perihelion will be:

Object Right Ascension Declination Constellation Magnitude
Comet C/2020 M3 (ATLAS) 05h06m40s 18°33'S Lepus 8.4

The coordinates are given in J2000.0.

The sky on 25 Oct 2020

The sky on 25 October 2020
Twilight ends
Twilight begins

9-day old moon
Waxing Gibbous


9 days old

Rise Culm. Set
Mercury 07:33 12:52 18:11
Venus 04:31 10:42 16:54
Moon 15:57 21:12 02:33
Mars 17:38 23:57 06:16
Jupiter 13:32 18:17 23:02
Saturn 13:52 18:41 23:30
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 19 Aug 2023.

Image credit

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





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