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🌎  Greenwich, United Kingdom [change]

Comet C/2020 S3 (Erasmus)

Comet C/2020 S3 (Erasmus) is currently in the constellation of Pegasus. The current Right Ascension of Comet C/2020 S3 (Erasmus) is 23h 07m 05s and the Declination is +09° 07’ 34” (topocentric coordinates computed for the selected location: Greenwich, United Kingdom [change]). The current estimated magnitude of Comet C/2020 S3 (Erasmus) is 19.73 (JPL).

Summary of key facts about Comet C/2020 S3 (Erasmus) [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]:

23h 07m 05s
+09° 07’ 34”
  • C/2020 S3 (Erasmus) is above the horizon from Greenwich, United Kingdom [change].
  • It is visible looking in the West-South-West direction at an altitude of 20° above the horizon.
  • Given its current magnitude, C/2020 S3 (Erasmus) is visible only through long exposure photography.
  • See also C/2020 S3 (Erasmus) 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 S3 (Erasmus) available on TheSkyLive:

Available Resources

Comet C/2020 S3 (Erasmus) Position and Finder Charts

Below we provide Comet C/2020 S3 (Erasmus) 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 S3 (Erasmus) in Pegasus on December, 08 2021
Field of view: 50x30 degrees
View fullscreen
Map showing Comet C/2020 S3 (Erasmus) in Pegasus on December, 08 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 S3 (Erasmus) is right now. Click on the image to see a more detailed fullscreen tracker view.

C/2020 S3 (Erasmus)
RA: 23h 07m 05s
Dec: +09° 07’ 34”
Deep sky finder chart for Comet C/2020 S3 (Erasmus)
Field of view: 60x40 arcmins
View fullscreen

Also check out Where is Comet C/2020 S3 (Erasmus)?, a page that provides all the information needed to find Comet C/2020 S3 (Erasmus) in the sky and additional links to sky charts.

Comet C/2020 S3 (Erasmus) Distance from Earth

The distance of Comet C/2020 S3 (Erasmus) from Earth is currently 751,407,631 kilometers, equivalent to 5.022850 Astronomical Units. Light takes 41 minutes and 46.4261 seconds to travel from Comet C/2020 S3 (Erasmus) and arrive to us.

41 minutes and 46.4261 seconds

The following chart shows the distance of Comet C/2020 S3 (Erasmus) 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 S3 (Erasmus) 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 S3 (Erasmus) from Earth is also available as a real time updated value in the Live Position and Data Tracker.

Closest approach of Comet C/2020 S3 (Erasmus) to Earth

Between January 2013 and December 2100, the closest approach of Comet C/2020 S3 (Erasmus) to Earth happens on Thu Nov 19 2020 at a distance of 1.037747 Astronomical Units, or 155,244,756 kilometers:

Thu Nov 19 2020

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

Comet C/2020 S3 (Erasmus) brightness

The current visual magnitude of Comet C/2020 S3 (Erasmus) is 19.73.


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 S3 (Erasmus), 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 S3 (Erasmus) between January 2013 and December 2100

Comet C/2020 S3 (Erasmus) 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 S3 (Erasmus) rise, transit and set times from Greenwich, United Kingdom [change] are the following (all times relative to the local timezone Europe/London):

Azimuth: 80.9°
Max altitude: 47.7°
Azimuth: 279.2°

The rise and set times are defined as the time at which the upper limb of Comet C/2020 S3 (Erasmus) 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 S3 (Erasmus) Orbital Elements

The following table lists the orbital elements of Comet C/2020 S3 (Erasmus) at epoch 06 March 2021 00:00 UTC (JD: 2459280.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.99795488
Orbit inclination i 19.86138985°
Perihelion distance q 0.39847240 AU
59,610,622 km
Aphelion distance Q 389.28325864 AU
58,235,946,708 km
Semi-major axis a 194.84086552 AU
29,147,778,665 km
Orbital period period 2,719.7456 years
993,387.0681 days
Date of perihelion transit Tp 2020-Dec-12 16:07:37
2,459,196.1720 JD
Next perihelion transit 4740-Oct-01 17:45
3,452,583.2400 JD
Argument of perihelion peri 349.88548513941°
Longitude of the ascending node node 222.99303034454°
Mean anomaly M 0.030560184155°
Mean motion n 0.00036240°/day

Visualization of Comet C/2020 S3 (Erasmus) Orbit

This 3d orbit diagram is a feature of our 3D Solar System Simulator and shows the orbit of Comet C/2020 S3 (Erasmus) with respect of the Sun and the orbits of the major planets. The position of Comet C/2020 S3 (Erasmus) 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 S3 (Erasmus)
View Comet C/2020 S3 (Erasmus) in the 3D Solar System Simulator

Comet C/2020 S3 (Erasmus) 15 Days Ephemeris

The following table lists the ephemerides of Comet C/2020 S3 (Erasmus) 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 S3 (Erasmus) in our Online Planetarium at the chosen date.

Date Right AscensionR.A. DeclinationDec. MagnitudeMag Constellation
2021 Dec 01 23h 05m 35s +09° 27’ 07” 19.60 Pegasus
2021 Dec 02 23h 05m 44s +09° 24’ 19” 19.62 Pegasus
2021 Dec 03 23h 05m 53s +09° 21’ 35” 19.63 Pegasus
2021 Dec 04 23h 06m 03s +09° 18’ 59” 19.65 Pegasus
2021 Dec 05 23h 06m 15s +09° 16’ 28” 19.67 Pegasus
2021 Dec 06 23h 06m 27s +09° 14’ 03” 19.68 Pegasus
2021 Dec 07 23h 06m 38s +09° 11’ 45” 19.70 Pegasus
2021 Dec 08 23h 06m 52s +09° 09’ 33” 19.71 Pegasus
2021 Dec 09 23h 07m 05s +09° 07’ 27” 19.73 Pegasus
2021 Dec 10 23h 07m 20s +09° 05’ 27” 19.74 Pegasus
2021 Dec 11 23h 07m 36s +09° 03’ 33” 19.76 Pegasus
2021 Dec 12 23h 07m 50s +09° 01’ 45” 19.77 Pegasus
2021 Dec 13 23h 08m 08s +09° 00’ 03” 19.79 Pegasus
2021 Dec 14 23h 08m 24s +08° 58’ 27” 19.80 Pegasus