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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
north SunriseRise: 6:47  
clear_day Transit: 12:50  
SunsetSet: 18:52 south
sunny DaytimeWhat's Visible Now
Comets » 

Comet C/2021 D1 (SWAN)

Altitude: 26.5°   Azimuth: 159.5°   Direction: South-South-East

Comet C/2021 D1 (SWAN) is currently in the constellation of Sextans. The current Right Ascension of Comet C/2021 D1 (SWAN) is 10h 42m 15s and the Declination is -09° 57’ 52” (topocentric coordinates computed for the selected location: Greenwich, United Kingdom edit_location_alt). The current estimated magnitude of Comet C/2021 D1 (SWAN) is 32.66 (JPL).

10h 42m 15s
-09° 57’ 52”

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 D1 (SWAN) from Greenwich, United Kingdom edit_location_alt (all times relative to the local timezone Europe/London):

Azimuth: 100.0°
Max altitude: 28.6°
Azimuth: 260.0°
  • C/2021 D1 (SWAN) is above the horizon from Greenwich, United Kingdom edit_location_alt.
  • Right now it is placed in the South-South-East direction at an altitude of 26° above the horizon.
  • Given its current magnitude, C/2021 D1 (SWAN) 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 D1 (SWAN) Position and Finder Charts

Below we provide Comet C/2021 D1 (SWAN) 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 D1 (SWAN) in Sextans on September,24 2023
Map showing Comet C/2021 D1 (SWAN) in Sextans on September, 24 2023
Field of view: 50x30 degrees
View fullscreen
Finder chart of C/2021 D1 (SWAN)
Map showing Comet C/2021 D1 (SWAN) in Sextans on September, 24 2023
Field of view: 10x6 degrees
View fullscreen

Higher precision deep sky finder chart, 60 arcmin wide, showing where Comet C/2021 D1 (SWAN) is right now. Click on the image to see a more detailed fullscreen tracker view.

C/2021 D1 (SWAN)
RA: 10h 42m 15s
Dec: -09° 57’ 52”
Deep sky finder chart for Comet C/2021 D1 (SWAN)
Field of view: 60x40 arcmins
View fullscreen

Also check out Where is Comet C/2021 D1 (SWAN)?, a page that provides all the information needed to find Comet C/2021 D1 (SWAN) in the sky and additional links to sky charts.

Comet C/2021 D1 (SWAN) Distance from Earth

The distance of Comet C/2021 D1 (SWAN) from Earth is currently 1,575,677,698 kilometers, equivalent to 10.532755 Astronomical Units. Light takes 1 hours, 27 minutes and 35.8951 seconds to travel from Comet C/2021 D1 (SWAN) and arrive to us.

1 hours, 27 minutes and 35.8951 seconds

The following chart shows the distance of Comet C/2021 D1 (SWAN) 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 D1 (SWAN) 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 D1 (SWAN) from Earth is also available as a real time updated value in the Live Position and Data Tracker.

Closest Approach of Comet C/2021 D1 (SWAN) to Earth

Between 1 January 2013 and 30 December 2100, the closest approach of Comet C/2021 D1 (SWAN) to Earth happens on Mon Mar 15 2021 at a distance of 1.676303 Astronomical Units, or 250,771,371 kilometers:

Mon Mar 15 2021

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

Comet C/2021 D1 (SWAN) Brightness and Light Curve

The following chart is the predicted light curve (visual magnitude as a function of time) of Comet C/2021 D1 (SWAN), 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 D1 (SWAN) as a function of time

Comet C/2021 D1 (SWAN) Orbital Elements

The following table lists the orbital elements of Comet C/2021 D1 (SWAN) at epoch 18 March 2021 00:00 UTC (JD: 2459292.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.99064883
Orbit inclination i 31.46078130°
Perihelion distance q 0.90179756 AU
134,906,996 km
Aphelion distance Q 191.97190787 AU
28,718,588,709 km
Semi-major axis a 96.43685272 AU
14,426,747,852 km
Orbital period period 947.0496 years
345,909.8823 days
Date of perihelion transit Tp 2021-Feb-27 14:36:45
2,459,273.1089 JD
Next perihelion transit 2968-Mar-24 11:47
2,805,182.9911 JD
Argument of perihelion peri 72.222961880732°
Longitude of the ascending node node 311.27122165418°
Mean anomaly M 0.02018100797481°
Mean motion n 0.00104073°/day

Visualization of Comet C/2021 D1 (SWAN) Orbit

This 3d orbit diagram is a feature of our 3D Solar System Simulator and shows the orbit of Comet C/2021 D1 (SWAN) with respect of the Sun and the orbits of the major planets. The position of Comet C/2021 D1 (SWAN) 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 D1 (SWAN)
View Comet C/2021 D1 (SWAN) in the 3D Solar System Simulator

Comet C/2021 D1 (SWAN) 15 Days Ephemeris

The following table lists the ephemerides of Comet C/2021 D1 (SWAN) 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 D1 (SWAN) in our Online Planetarium at the chosen date.

Date Right AscensionR.A. DeclinationDec. MagnitudeMag Constellation
2023 Sep 17 10h 39m 34s -09° 35’ 00” 32.62 Sextans
2023 Sep 18 10h 39m 56s -09° 38’ 03” 32.63 Sextans
2023 Sep 19 10h 40m 18s -09° 41’ 08” 32.63 Sextans
2023 Sep 20 10h 40m 41s -09° 44’ 12” 32.64 Sextans
2023 Sep 21 10h 41m 02s -09° 47’ 17” 32.65 Sextans
2023 Sep 22 10h 41m 23s -09° 50’ 23” 32.65 Sextans
2023 Sep 23 10h 41m 44s -09° 53’ 30” 32.66 Sextans
2023 Sep 24 10h 42m 06s -09° 56’ 39” 32.66 Sextans
2023 Sep 25 10h 42m 28s -09° 59’ 47” 32.67 Sextans
2023 Sep 26 10h 42m 48s -10° 02’ 56” 32.67 Sextans
2023 Sep 27 10h 43m 09s -10° 06’ 06” 32.68 Sextans
2023 Sep 28 10h 43m 29s -10° 09’ 15” 32.68 Sextans
2023 Sep 29 10h 43m 50s -10° 12’ 26” 32.69 Sextans
2023 Sep 30 10h 44m 11s -10° 15’ 38” 32.69 Sextans