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

Comet C/2023 E1 (ATLAS) passes perigee

Dominic Ford, Editor
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Comet C/2023 E1 (ATLAS) will make its closest approach to the Earth on 18 August, at a distance of of 0.37 AU.

From Ashburn on the day of perigee it will be visible all night. It will become visible at around 21:09 (EST), 43° above your eastern horizon, as dusk fades to darkness. It will then reach its highest point in the sky at 01:09, 86° above your southern horizon. It will be lost to dawn twilight at around 05:14, 41° above your western horizon.

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The events that comprise the 2023 apparition of C/2023 E1 (ATLAS) are as follows:

Date Event
01 Jul 2023Comet C/2023 E1 (ATLAS) passes perihelion
15 Jul 2023Comet C/2023 E1 (ATLAS) reaches peak brightness
18 Aug 2023Comet C/2023 E1 (ATLAS) passes perigee

The table below lists the times when C/2023 E1 (ATLAS) will be visible from Ashburn day-by-day through its apparition:

Date Constellation Comet visibility
28 Jul 2023DracoVisible from 21:39 until 04:49
Highest at 01:24, 59° above N horizon
30 Jul 2023CepheusVisible from 21:37 until 04:52
Highest at 01:28, 62° above N horizon
01 Aug 2023CepheusVisible from 21:34 until 04:54
Highest at 01:30, 64° above N horizon
03 Aug 2023CepheusVisible from 21:31 until 04:56
Highest at 01:30, 67° above N horizon
05 Aug 2023CepheusVisible from 21:29 until 04:59
Highest at 01:30, 70° above N horizon
07 Aug 2023CepheusVisible from 21:26 until 05:01
Highest at 01:28, 73° above N horizon
09 Aug 2023CygnusVisible from 21:23 until 05:03
Highest at 01:26, 77° above N horizon
11 Aug 2023CygnusVisible from 21:20 until 05:06
Highest at 01:23, 80° above N horizon
13 Aug 2023CygnusVisible from 21:17 until 05:08
Highest at 01:20, 84° above N horizon
15 Aug 2023CygnusVisible from 21:14 until 05:10
Highest at 01:16, 88° above N horizon
17 Aug 2023CygnusVisible from 21:11 until 05:13
Highest at 01:12, 88° above S horizon
19 Aug 2023CygnusVisible from 21:08 until 05:15
Highest at 01:07, 83° above S horizon
21 Aug 2023PegasusVisible from 21:04 until 05:17
Highest at 01:02, 79° above S horizon
23 Aug 2023PegasusVisible from 21:01 until 05:20
Highest at 00:57, 75° above S horizon
25 Aug 2023PegasusVisible from 20:58 until 05:22
Highest at 00:51, 71° above S horizon
27 Aug 2023PegasusVisible from 20:55 until 05:24
Highest at 00:46, 67° above S horizon
29 Aug 2023PegasusVisible from 20:51 until 05:25
Highest at 00:40, 63° above S horizon
31 Aug 2023PegasusVisible from 20:48 until 05:08
Highest at 00:34, 59° above S horizon
02 Sep 2023PegasusVisible from 20:44 until 04:50
Highest at 00:28, 56° above S horizon
04 Sep 2023AquariusVisible from 20:41 until 04:33
Highest at 00:22, 53° above S horizon
06 Sep 2023AquariusVisible from 20:37 until 04:17
Highest at 00:15, 50° above S horizon

A more detailed table of C/2023 E1 (ATLAS)'s position on each night is available here. A diagram of the orbit of C/2023 E1 (ATLAS) is available here.

Finder chart

The chart below shows the path of C/2023 E1 (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.

Based on the magnitude parameters published for this comet by the BAA Comet Section, we estimate that it may be around mag 7 on 18 August 2023. 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 perigee will be:

Object Right Ascension Declination Constellation Magnitude
Comet C/2023 E1 (ATLAS) 21h44m10s 35°37'N Cygnus 7.3

The coordinates are given in J2000.0.

The sky on 18 Aug 2023

The sky on 18 August 2023
Twilight ends
Twilight begins

2-day old moon
Waxing Crescent


2 days old

Rise Culm. Set
Mercury 08:36 14:41 20:47
Venus 06:01 12:30 19:00
Moon 08:18 14:54 21:20
Mars 08:48 15:01 21:14
Jupiter 23:21 06:14 13:08
Saturn 20:26 01:51 07:15
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 06 Oct 2023.

Image credit

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





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