Your Guide to the Solar System and the Night Sky
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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
north SunriseRise: 4:52  
clear_day Transit: 12:55  
SunsetSet: 20:59 south
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Breakng! newly discovered Supernova 2023ixf in the Pinwheel Galaxy is the closest supernova observed in the latest decade. It can become bright enough to be visible by amateur astronomers. Check out information and detailed finder chart.
Comets » 

Comet C/2021 A4 (NEOWISE)

Comet C/2021 A4 (NEOWISE) is currently in the constellation of Pisces Austrinus.

The current Right Ascension of Comet C/2021 A4 (NEOWISE) is 21h 55m 55s and the Declination is -30° 09’ 40” (topocentric coordinates computed for the selected location: Greenwich, United Kingdom edit_location_alt). The current estimated magnitude of Comet C/2021 A4 (NEOWISE) is 44.22 (JPL).

21h 55m 55s
-30° 09’ 40”
Pisces Austrinus

The observed values of Magnitude, Coma Diameter and Tail Length are derived from the most recent observation recorded at the Comet Observers Database. The value of Predicted Magnitude comes from the JPL Horizons ephemerides service and, in the case of comets, might be inaccurate given the highly dynamic and unpredictable behavior of these objects. When available, please refer to the Observed Magnitude value and consider the Predicted 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.

Today's rise, transit and set times of Comet C/2021 A4 (NEOWISE) from Greenwich, United Kingdom edit_location_alt (all times relative to the local timezone Europe/London):

Azimuth: 120.2°
Max altitude: 8.4°
Azimuth: 239.8°
  • C/2021 A4 (NEOWISE) is below the horizon from Greenwich, United Kingdom edit_location_alt.
  • Given its current magnitude, C/2021 A4 (NEOWISE) 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 A4 (NEOWISE) Position and Finder Charts

Below we provide Comet C/2021 A4 (NEOWISE) 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.

Finder chart of C/2021 A4 (NEOWISE) in Pisces Austrinus on May,28 2023
Map showing Comet C/2021 A4 (NEOWISE) in Pisces Austrinus on May, 28 2023
Field of view: 50x30 degrees
View fullscreen
Finder chart of C/2021 A4 (NEOWISE)
Map showing Comet C/2021 A4 (NEOWISE) in Pisces Austrinus on May, 28 2023
Field of view: 10x6 degrees
View fullscreen

Higher precision deep sky finder chart, 60 arcmin wide, showing where Comet C/2021 A4 (NEOWISE) is right now. Click on the image to see a more detailed fullscreen tracker view.

C/2021 A4 (NEOWISE)
RA: 21h 55m 55s
Dec: -30° 09’ 40”
Deep sky finder chart for Comet C/2021 A4 (NEOWISE)
Field of view: 60x40 arcmins
View fullscreen

Also check out Where is Comet C/2021 A4 (NEOWISE)?, a page that provides all the information needed to find Comet C/2021 A4 (NEOWISE) in the sky and additional links to sky charts.

Comet C/2021 A4 (NEOWISE) Distance from Earth

The distance of Comet C/2021 A4 (NEOWISE) from Earth is currently 1,186,956,782 kilometers, equivalent to 7.934316 Astronomical Units. Light takes 1 hours, 5 minutes and 59.2617 seconds to travel from Comet C/2021 A4 (NEOWISE) and arrive to us.

1 hours, 5 minutes and 59.2617 seconds

The following chart shows the distance of Comet C/2021 A4 (NEOWISE) 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 A4 (NEOWISE) 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 A4 (NEOWISE) from Earth is also available as a real time updated value in the Live Position and Data Tracker.

Closest Approach of Comet C/2021 A4 (NEOWISE) to Earth

Between 1 January 2013 and 30 December 2100, the closest approach of Comet C/2021 A4 (NEOWISE) to Earth happens on Fri Feb 12 2021 at a distance of 0.433930 Astronomical Units, or 64,915,004 kilometers:

Fri Feb 12 2021

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

Comet C/2021 A4 (NEOWISE) Brightness and Light Curve

The following chart is the predicted light curve (visual magnitude as a function of time) of Comet C/2021 A4 (NEOWISE), 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 A4 (NEOWISE) as a function of time

Comet C/2021 A4 (NEOWISE) Orbital Elements

The following table lists the orbital elements of Comet C/2021 A4 (NEOWISE) at epoch 15 February 2021 00:00 UTC (JD: 2459261.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.97324748
Orbit inclination i 111.56983372°
Perihelion distance q 1.14547639 AU
171,360,829 km
Aphelion distance Q 84.48956049 AU
12,639,458,371 km
Semi-major axis a 42.81751844 AU
6,405,409,600 km
Orbital period period 280.1821 years
102,336.5253 days
Date of perihelion transit Tp 2021-Mar-20 00:53:23
2,459,293.5371 JD
Next perihelion transit 2301-May-28 13:29
2,561,630.0624 JD
Argument of perihelion peri 204.66556616438°
Longitude of the ascending node node 307.08476248258°
Mean anomaly M 359.8872997811°
Mean motion n 0.00351781°/day

Visualization of Comet C/2021 A4 (NEOWISE) Orbit

This 3d orbit diagram is a feature of our 3D Solar System Simulator and shows the orbit of Comet C/2021 A4 (NEOWISE) with respect of the Sun and the orbits of the major planets. The position of Comet C/2021 A4 (NEOWISE) 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/2021 A4 (NEOWISE)
View Comet C/2021 A4 (NEOWISE) in the 3D Solar System Simulator

Comet C/2021 A4 (NEOWISE) 15 Days Ephemeris

The following table lists the ephemerides of Comet C/2021 A4 (NEOWISE) 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 A4 (NEOWISE) in our Online Planetarium at the chosen date.

Date Right AscensionR.A. DeclinationDec. MagnitudeMag Constellation
2023 May 21 21h 56m 57s -29° 58’ 37” 44.16 Pisces Austrinus
2023 May 22 21h 56m 51s -30° 00’ 06” 44.17 Pisces Austrinus
2023 May 23 21h 56m 43s -30° 01’ 35” 44.18 Pisces Austrinus
2023 May 24 21h 56m 35s -30° 03’ 07” 44.19 Pisces Austrinus
2023 May 25 21h 56m 25s -30° 04’ 41” 44.19 Pisces Austrinus
2023 May 26 21h 56m 16s -30° 06’ 19” 44.20 Pisces Austrinus
2023 May 27 21h 56m 05s -30° 07’ 58” 44.21 Pisces Austrinus
2023 May 28 21h 55m 54s -30° 09’ 39” 44.22 Pisces Austrinus
2023 May 29 21h 55m 44s -30° 11’ 22” 44.23 Pisces Austrinus
2023 May 30 21h 55m 32s -30° 13’ 09” 44.24 Pisces Austrinus
2023 May 31 21h 55m 18s -30° 14’ 57” 44.25 Pisces Austrinus
2023 Jun 01 21h 55m 05s -30° 16’ 46” 44.26 Pisces Austrinus
2023 Jun 02 21h 54m 52s -30° 18’ 38” 44.26 Pisces Austrinus
2023 Jun 03 21h 54m 38s -30° 20’ 31” 44.27 Pisces Austrinus