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🌎 Location: Greenwich, United Kingdom [change]

Comet C/2020 R4 (ATLAS)

Comet C/2020 R4 (ATLAS) is currently in the constellation of Capricornus. The current Right Ascension of Comet C/2020 R4 (ATLAS) is 21h 03m 54s and the Declination is -16° 45’ 07” (topocentric coordinates computed for the selected location: Greenwich, United Kingdom [change]). The current estimated magnitude of Comet C/2020 R4 (ATLAS) is 15.17 (JPL) while the latest observed magnitude is 9.5 (COBS).

Summary of key facts about Comet C/2020 R4 (ATLAS) [tip: you can also create a Quick Access page for this data if you access it frequently and would like to have a simpler view]:

21h 03m 54s
-16° 45’ 07”
  • C/2020 R4 (ATLAS) is above the horizon from Greenwich, United Kingdom [change].
  • It is visible looking in the South-South-West direction at an altitude of 16° above the horizon.
  • Given its current magnitude, C/2020 R4 (ATLAS) is visible with the help of a binocular with a 80mm aperture or a small telescope.
  • See also C/2020 R4 (ATLAS) rise and set times.
  • Go to interactive sky chart

If you need to access this information frequently for your observations, you can create a simple customized Quick Access page, so that you can easily bookmark it in your browser favorites or add a shortcut to your mobile phones' home screen.

Additional information about Comet C/2020 R4 (ATLAS) available on TheSkyLive:

Available Resources

Comet C/2020 R4 (ATLAS) Position and Finder Charts

Below we provide Comet C/2020 R4 (ATLAS) finder charts showing where the object is right now in the sky with respect to the brightest stars. The first finder chart has a field of view of 50 degrees, while the second one has a field of view of 10 degrees. Click on each finder chart to access a full screen interactive Online Planetarium.

Map showing Comet C/2020 R4 (ATLAS) in Capricornus on January, 21 2021
Field of view: 50x30 degrees
View fullscreen
Map showing Comet C/2020 R4 (ATLAS) in Capricornus on January, 21 2021
Field of view: 10x6 degrees
View fullscreen
 = visible to the naked eye
 = binocular, brighter than 10th magnitude
= current altitude ≥ 30°   = current altitude < 30°   = below the horizon
Location: Greenwich, United Kingdom [change]

Higher precision deep sky finder chart, 60 arcmin wide, showing where Comet C/2020 R4 (ATLAS) is right now. Click on the image to see a more detailed fullscreen tracker view.

C/2020 R4 (ATLAS)
RA: 21h 03m 54s
Dec: -16° 45’ 07”
Deep sky finder chart for Comet C/2020 R4 (ATLAS)
Field of view: 60x40 arcmins
View fullscreen

Also check out Where is Comet C/2020 R4 (ATLAS)?, a page that provides all the information needed to find Comet C/2020 R4 (ATLAS) in the sky and additional links to sky charts.

Comet C/2020 R4 (ATLAS) Distance from Earth

The distance of Comet C/2020 R4 (ATLAS) from Earth is currently 323,659,902 kilometers, equivalent to 2.163533 Astronomical Units. Light takes 17 minutes and 59.6132 seconds to travel from Comet C/2020 R4 (ATLAS) and arrive to us.

17 minutes and 59.6132 seconds

The following chart shows the distance of Comet C/2020 R4 (ATLAS) from Earth as a function of time. In the chart the distance data is measured in Astronomical Units and sampled with an interval of 1 day.

Distance of Comet C/2020 R4 (ATLAS) from Earth between January 2013 and December 2100

The value of the reported distance might be somewhat inaccurate around the times of closest approach for objects passing extremely close to Earth. The value of the distance of C/2020 R4 (ATLAS) from Earth is also available as a real time updated value in the Live Position and Data Tracker.

Closest approach of Comet C/2020 R4 (ATLAS) to Earth

Between January 2013 and December 2100, the closest approach of Comet C/2020 R4 (ATLAS) to Earth happens on Fri Apr 23 2021 at a distance of 0.463644 Astronomical Units, or 69,360,189 kilometers:

Fri Apr 23 2021

NOTE: values for the closest approach are computed with a sampling interval of 1 day.

Comet C/2020 R4 (ATLAS) brightness

The current visual magnitude of Comet C/2020 R4 (ATLAS) is 15.17.


The observed magnitude and coma diameter values are derived from the Comet Observers Database by averaging the values reported in recent observations (more recent than 4 days), when available. The Estimated Magnitude comes from the JPL Horizons ephemerides service and might be inaccurate given the highly dynamic and unpredictable behavior of comets. When available, please refer to the Observed Magnitude value and consider the Estimated Magnitude as a directional indication. We acknowledge with thanks the comet observations from the COBS Comet Observation Database contributed by observers worldwide and used in this table to report recent comet observations.

The following chart is the predicted light curve (visual magnitude as a function of time) of Comet C/2020 R4 (ATLAS), according to the most recent ephemerides data. Magnitude data is sampled with a 2 days interval and there might be inaccuracies for objects changing brightness very rapidly during the course of a few days. For comets there could be large discrepancies between the observed and predicted brightness because of their highly dynamic behaviour.

Predicted magnitude of Comet C/2020 R4 (ATLAS) between January 2013 and December 2100

Comet C/2020 R4 (ATLAS) rise and set times

Location: Greenwich, United Kingdom [change]
Latitude: 51° 28’ 47” N
Longitude: 0° 00’ 00” E
Timezone: Europe/London

Today's Comet C/2020 R4 (ATLAS) rise, transit and set times from Greenwich, United Kingdom [change] are the following (all times relative to the local timezone Europe/London):

Azimuth: 106.8°
Max altitude: 21.8°
Azimuth: 253.3°

The rise and set times are defined as the time at which the upper limb of Comet C/2020 R4 (ATLAS) touches the horizon, considering the effect of the atmospheric refraction. As the atmospheric conditions cannot be modeled precisely the times reported here should be considered correct with an approximation of few minutes.

Comet C/2020 R4 (ATLAS) Orbital Elements

The following table lists the orbital elements of Comet C/2020 R4 (ATLAS) at epoch 24 October 2020 00:00 UTC (JD: 2459147.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.98923436
Orbit inclination i 164.46249950°
Perihelion distance q 1.02832966 AU
153,835,927 km
Aphelion distance Q 190.01087086 AU
28,425,221,747 km
Semi-major axis a 95.51960026 AU
14,289,528,837 km
Orbital period period 933.5700 years
340,986.4891 days
Date of perihelion transit Tp 2021-Mar-01 22:43:07
2,459,275.4466 JD
Argument of perihelion peri 46.734322115021°
Longitude of the ascending node node 323.27653743101°
Mean anomaly M 359.86491904769°
Mean motion n 0.00105576°/day

Visualization of Comet C/2020 R4 (ATLAS) Orbit

This 3d orbit diagram is a feature of our 3D Solar System Simulator and shows the orbit of Comet C/2020 R4 (ATLAS) with respect of the Sun and the orbits of the major planets. The position of Comet C/2020 R4 (ATLAS) and the planets along their orbits in this diagram accurately represents the current configuration of the objects in the Solar System. This is an experimental feature and it requires a WebGL enabled browser. Please provide us feedback!

Orbit Diagram of Comet C/2020 R4 (ATLAS)
View Comet C/2020 R4 (ATLAS) in the 3D Solar System Simulator

Comet C/2020 R4 (ATLAS) 15 Days Ephemeris

The following table lists the ephemerides of Comet C/2020 R4 (ATLAS) computed for the past and next 7 days, with a 24 hours interval. Click on each row of the table to locate Comet C/2020 R4 (ATLAS) in our Online Planetarium at the chosen date.

Date Right AscensionR.A. DeclinationDec. MagnitudeMag Constellation
2021 Jan 14 21h 08m 13s -17° 34’ 50” 15.51 Capricornus
2021 Jan 15 21h 07m 39s -17° 28’ 23” 15.47 Capricornus
2021 Jan 16 21h 07m 04s -17° 21’ 53” 15.43 Capricornus
2021 Jan 17 21h 06m 29s -17° 15’ 24” 15.38 Capricornus
2021 Jan 18 21h 05m 56s -17° 08’ 53” 15.34 Capricornus
2021 Jan 19 21h 05m 21s -17° 02’ 21” 15.29 Capricornus
2021 Jan 20 21h 04m 49s -16° 55’ 47” 15.25 Capricornus
2021 Jan 21 21h 04m 14s -16° 49’ 13” 15.20 Capricornus
2021 Jan 22 21h 03m 42s -16° 42’ 37” 15.16 Capricornus
2021 Jan 23 21h 03m 10s -16° 35’ 57” 15.12 Capricornus
2021 Jan 24 21h 02m 36s -16° 29’ 17” 15.07 Capricornus
2021 Jan 25 21h 02m 04s -16° 22’ 36” 15.03 Capricornus
2021 Jan 26 21h 01m 32s -16° 15’ 51” 14.98 Capricornus
2021 Jan 27 21h 01m 00s -16° 09’ 05” 14.94 Capricornus