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🌎  Observing from: Greenwich, United Kingdom [change]
🌅 Sunrise: 6:38  ☀️ Transit: 13:03  🌅 Sunset: 19:28

Comet C/2021 A2

Comet C/2021 A2 is currently in the constellation of Cygnus. The current Right Ascension of Comet C/2021 A2 is 21h 21m 01s and the Declination is +47° 55’ 50” (topocentric coordinates computed for the selected location: Greenwich, United Kingdom [change]). The current estimated magnitude of Comet C/2021 A2 is 23.82 (JPL).

21h 21m 01s
+47° 55’ 50”

Today's rise, transit and set times of Comet C/2021 A2 from Greenwich, United Kingdom [change] (all times relative to the local timezone Europe/London):

Today Comet C/2021 A2 is circumpolar and transits at 08:47 UTC reaching a maximum altitude of 86.5°.
  • C/2021 A2 is above the horizon from Greenwich, United Kingdom [change].
  • Right now it is placed in the North-North-East direction at an altitude of 12° above the horizon.
  • Given its current magnitude, C/2021 A2 is visible only through long exposure photography.
  • 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.

Available Resources

Comet C/2021 A2 Position and Finder Charts

Below we provide Comet C/2021 A2 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/2021 A2 in Cygnus on March, 31 2023
Field of view: 50x30 degrees
View fullscreen
Map showing Comet C/2021 A2 in Cygnus on March, 31 2023
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/2021 A2 is right now. Click on the image to see a more detailed fullscreen tracker view.

C/2021 A2
RA: 21h 21m 01s
Dec: +47° 55’ 50”
Deep sky finder chart for Comet C/2021 A2
Field of view: 60x40 arcmins
View fullscreen

Also check out Where is Comet C/2021 A2?, a page that provides all the information needed to find Comet C/2021 A2 in the sky and additional links to sky charts.

Comet C/2021 A2 Distance from Earth

The distance of Comet C/2021 A2 from Earth is currently 1,299,699,918 kilometers, equivalent to 8.687957 Astronomical Units. Light takes 1 hours, 12 minutes and 15.3323 seconds to travel from Comet C/2021 A2 and arrive to us.

1 hours, 12 minutes and 15.3323 seconds

The following chart shows the distance of Comet C/2021 A2 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.

Chart of the distance of Comet C/2021 A2 from Earth in Astronomical Units (au)

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/2021 A2 from Earth is also available as a real time updated value in the Live Position and Data Tracker.

Closest Approach of Comet C/2021 A2 to Earth

Between 1 January 2013 and 30 December 2100, the closest approach of Comet C/2021 A2 to Earth happens on Wed Feb 3 2021 at a distance of 0.506733 Astronomical Units, or 75,806,248 kilometers:

Wed Feb 3 2021

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

Comet C/2021 A2 Brightness

The current visual magnitude of Comet C/2021 A2 is 23.82.


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/2021 A2, 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.

Chart of the magnitude of Comet C/2021 A2 as a function of time

Comet C/2021 A2 Orbital Elements

The following table lists the orbital elements of Comet C/2021 A2 at epoch 20 February 2021 00:00 UTC (JD: 2459266.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.99452815
Orbit inclination i 106.97835893°
Perihelion distance q 1.41297511 AU
211,378,068 km
Aphelion distance Q 515.03952623 AU
77,048,816,605 km
Semi-major axis a 258.22625067 AU
38,630,097,337 km
Orbital period period 4,149.6244 years
1,515,650.3047 days
Date of perihelion transit Tp 2021-Jan-22 15:13:12
2,459,237.1342 JD
Next perihelion transit 6170-Oct-08 22:31
3,974,887.4389 JD
Argument of perihelion peri 338.84903384462°
Longitude of the ascending node node 125.23825155612°
Mean anomaly M 0.0069750251957052°
Mean motion n 0.00023752°/day

Visualization of Comet C/2021 A2 Orbit

This 3d orbit diagram is a feature of our 3D Solar System Simulator and shows the orbit of Comet C/2021 A2 with respect of the Sun and the orbits of the major planets. The position of Comet C/2021 A2 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!

Comet C/2021 A2 15 Days Ephemeris

The following table lists the ephemerides of Comet C/2021 A2 computed for the past and next 7 days, with a 24 hours interval. Click on each row of the table to locate Comet C/2021 A2 in our Online Planetarium at the chosen date.

Date Right AscensionR.A. DeclinationDec. MagnitudeMag Constellation
2023 Mar 24 21h 18m 02s +47° 24’ 14” 23.79 Cygnus
2023 Mar 25 21h 18m 25s +47° 28’ 03” 23.80 Cygnus
2023 Mar 26 21h 18m 50s +47° 31’ 54” 23.80 Cygnus
2023 Mar 27 21h 19m 14s +47° 35’ 49” 23.80 Cygnus
2023 Mar 28 21h 19m 36s +47° 39’ 48” 23.81 Cygnus
2023 Mar 29 21h 19m 59s +47° 43’ 49” 23.81 Cygnus
2023 Mar 30 21h 20m 21s +47° 47’ 53” 23.81 Cygnus
2023 Mar 31 21h 20m 41s +47° 51’ 59” 23.82 Cygnus
2023 Apr 01 21h 21m 02s +47° 56’ 08” 23.82 Cygnus
2023 Apr 02 21h 21m 23s +48° 00’ 20” 23.82 Cygnus
2023 Apr 03 21h 21m 42s +48° 04’ 33” 23.82 Cygnus
2023 Apr 04 21h 22m 02s +48° 08’ 49” 23.83 Cygnus
2023 Apr 05 21h 22m 22s +48° 13’ 08” 23.83 Cygnus
2023 Apr 06 21h 22m 40s +48° 17’ 29” 23.83 Cygnus