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Comet C/2021 A4 (NEOWISE)

Comet C/2021 A4 (NEOWISE) is currently in the constellation of Eridanus. The current Right Ascension of Comet C/2021 A4 (NEOWISE) is 04h 16m 54s and the Declination is -17° 03’ 41” (topocentric coordinates computed for the selected location: Greenwich, United Kingdom [change]). The current estimated magnitude of Comet C/2021 A4 (NEOWISE) is 19.09 (JPL).

Summary of key facts about Comet C/2021 A4 (NEOWISE) [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]:

04h 16m 54s
-17° 03’ 41”

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Additional information about Comet C/2021 A4 (NEOWISE) available on TheSkyLive:

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.

Map showing Comet C/2021 A4 (NEOWISE) in Eridanus on May, 07 2021
Field of view: 50x30 degrees
View fullscreen
Map showing Comet C/2021 A4 (NEOWISE) in Eridanus on May, 07 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/2021 A4 (NEOWISE) is right now. Click on the image to see a more detailed fullscreen tracker view.

C/2021 A4 (NEOWISE)
RA: 04h 16m 54s
Dec: -17° 03’ 41”
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 299,759,728 kilometers, equivalent to 2.003770 Astronomical Units. Light takes 16 minutes and 39.8908 seconds to travel from Comet C/2021 A4 (NEOWISE) and arrive to us.

16 minutes and 39.8908 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.

Distance of Comet C/2021 A4 (NEOWISE) 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/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 January 2013 and December 2100, the closest approach of Comet C/2021 A4 (NEOWISE) to Earth happens on Fri Feb 12 2021 at a distance of 0.433936 Astronomical Units, or 64,915,964 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

The current visual magnitude of Comet C/2021 A4 (NEOWISE) is 19.09.


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 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.

Predicted magnitude of Comet C/2021 A4 (NEOWISE) between January 2013 and December 2100

Comet C/2021 A4 (NEOWISE) 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/2021 A4 (NEOWISE) rise, transit and set times from Greenwich, United Kingdom [change] are the following (all times relative to the local timezone Europe/London):

Azimuth: 106.9°
Max altitude: 21.5°
Azimuth: 253.0°

The rise and set times are defined as the time at which the upper limb of Comet C/2021 A4 (NEOWISE) 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/2021 A4 (NEOWISE) Orbital Elements

The following table lists the orbital elements of Comet C/2021 A4 (NEOWISE) at epoch 12 February 2021 00:00 UTC (JD: 2459258.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.97331110
Orbit inclination i 111.57040609°
Perihelion distance q 1.14548629 AU
171,362,310 km
Aphelion distance Q 84.69442126 AU
12,670,105,105 km
Semi-major axis a 42.91995377 AU
6,420,733,708 km
Orbital period period 281.1900 years
102,703.9851 days
Date of perihelion transit Tp 2021-Mar-20 00:51:06
2,459,293.5355 JD
Next perihelion transit 2302-May-31 00:29
2,561,997.5206 JD
Argument of perihelion peri 204.66395110897°
Longitude of the ascending node node 307.08444515055°
Mean anomaly M 359.8771929344°
Mean motion n 0.00350522°/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
2021 Apr 30 04h 15m 01s -15° 13’ 36” 18.42 Eridanus
2021 May 01 04h 15m 14s -15° 27’ 29” 18.51 Eridanus
2021 May 02 04h 15m 27s -15° 41’ 22” 18.59 Eridanus
2021 May 03 04h 15m 41s -15° 55’ 14” 18.67 Eridanus
2021 May 04 04h 15m 55s -16° 09’ 02” 18.76 Eridanus
2021 May 05 04h 16m 09s -16° 22’ 53” 18.84 Eridanus
2021 May 06 04h 16m 24s -16° 36’ 42” 18.93 Eridanus
2021 May 07 04h 16m 40s -16° 50’ 34” 19.01 Eridanus
2021 May 08 04h 16m 54s -17° 04’ 26” 19.09 Eridanus
2021 May 09 04h 17m 11s -17° 18’ 20” 19.18 Eridanus
2021 May 10 04h 17m 26s -17° 32’ 16” 19.26 Eridanus
2021 May 11 04h 17m 43s -17° 46’ 14” 19.35 Eridanus
2021 May 12 04h 17m 59s -18° 00’ 17” 19.43 Eridanus
2021 May 13 04h 18m 16s -18° 14’ 23” 19.51 Eridanus