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Comet C/2021 A1 (Leonard)

Below the horizon.  Rise: 15:44 | Tran: 21:15 | Set: 2:50
Alt: -21.08°   Az: 288.85°   Direction: West-North-West

Comet C/2021 A1 (Leonard) is in the constellation of Libra, at a distance of 1,775,944,051.0 kilometers from Earth. The current Right Ascension is 15h 59m 09s and the Declination is -05° 22’ 22” (apparent coordinates). The estimated magnitude of comet C/2021 A1 (Leonard), computed using JPL Horizons's data, is 22.80.

Finder Charts

The sky charts below show, at different resolutions, the position of comet C/2021 A1 (Leonard) in the sky. Click on each chart to access the interactive star map tool.

Star map showing the position of comet C/2021 A1 (Leonard) in the constellation of Libra on F, d Y. Field of view: 50x30 degrees. View interactive star map.
Star map showing the position of comet C/2021 A1 (Leonard) in the constellation of Libra on F, d Y. Field of view: 15x9 degrees. View in interactive star map.

The following map uses photographic imagery from the Digitized Sky Survey (DSS) to realistically visualize the precise position of comet C/2021 A1 (Leonard) against the stars in the background. The horizontal size of the map measures 60 arcminutes. Click on the image to access a more detailed full-screen view.

C/2021 A1 (Leonard)
RA: 15h 57m 47s
Dec: -05° 18’ 03”
Simplified high-resolution deep sky chart showing the current position of comet C/2021 A1 (Leonard). Field of view: 60 x 40 arcminutes. Go to the dedicated page

Equatorial Coordinates

Apparent

15h 59m 09s
-05° 22’ 22”
07h 50m 02s
23h 49m 11s

J2000

15h 57m 47s
-05° 18’ 03”

Additional Information

Libra
n/a
n/a
n/a
n/a
22.80

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.

Rise and Set Times

The following table lists today's rise, transit and set times of comet C/2021 A1 (Leonard) from Greenwich, UK (all times relative to the local timezone Europe/London):

Azimuth: 95.4°
Max altitude: 33.1°
Azimuth: 264.6°

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.

Distance from Earth

The distance of comet C/2021 A1 (Leonard) from Earth is currently 1,775,944,051.0 kilometers, equivalent to 11.8714527332 Astronomical Units. Light takes 1h 38m 43.912s to travel from comet C/2021 A1 (Leonard) and arrive to us.

1,775,944,051.0
11.8714527332
1h 38m 43.912s

The following graph shows the distance of comet C/2021 A1 (Leonard) from Earth as a function of time. In the chart the distance is measured in Astronomical Units and the data is sampled with an interval of 1 day.

Chart of the distance of comet C/2021 A1 (Leonard) from Earth in Astronomical Units (au)
Note: The values in this chart may not be entirely accurate around the time of closest approach for objects passing very close to Earth at high speed (e.g., Near-Earth Objects).

The value of the distance of C/2021 A1 (Leonard) from Earth is also available as a real time updated value in the live position tracker.

Closest Approach to Earth

In the period between January 1, 2000 and December 31, 2099, the closest approach of comet C/2021 A1 (Leonard) to Earth happened on Monday 13 December 2021 at a distance of 0.233994 Astronomical Units, or 35,005,003 kilometers:

Monday 13 December 2021
35,005,003
0.233994

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

Light Curve

The following chart shows the light curve of comet C/2021 A1 (Leonard), i.e., its apparent magnitude as a function of time. The curve is calculated using the latest ephemerides provided by JPL Horizons. The magnitude data is sampled with the interval of 2 days. Because of this sampling, inaccuracies may occur for objects that have large variations of brightness over a few days. For comets, large discrepancies can arise between the calculated brightness and the observations due to their highly dynamic, and not always precisely predictable, behavior.

Chart of the magnitude of comet C/2021 A1 (Leonard) as a function of time

Orbital Elements

The following table lists the orbital elements of comet C/2021 A1 (Leonard) at epoch July, 10 2021 00:00 UTC (JD: 2459406.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 1.00010048
Orbit inclination i 132.68581262°
Perihelion distance q 0.61523019 AU
92,037,127 km
Aphelion distance Q n.a.
Semi-major axis a n.a.
Orbital period period n.a.
Date of perihelion transit Tp January 3, 2022
2,459,582.7927 JD
Argument of perihelion peri 225.08771303871°
Longitude of the ascending node node 255.88910373877°
Mean anomaly M -0.00036266407886569°
Mean motion n 0.00000206°/day

Orbit Visualization

The following chart is a 3D animated visualization of the orbit of comet C/2021 A1 (Leonard) relative to the other major objects in the Solar System. You can access more advanced features using our 3D Solar System Viewer.

15 Days Ephemeris

The following table lists the ephemerides of comet C/2021 A1 (Leonard) computed for the past and next 7 days, with a 24 hours interval. Apparent celestial coordinates are provided.

Date Right AscensionR.A. DeclinationDec. MagnitudeMag Constellation
Jul 10 2025 16h 00m 43s -05° 22’ 03” 22.77 Libra
Jul 11 2025 16h 00m 29s -05° 22’ 00” 22.77 Libra
Jul 12 2025 16h 00m 15s -05° 22’ 00” 22.78 Libra
Jul 13 2025 16h 00m 01s -05° 22’ 01” 22.78 Libra
Jul 14 2025 15h 59m 48s -05° 22’ 04” 22.79 Libra
Jul 15 2025 15h 59m 35s -05° 22’ 08” 22.79 Libra
Jul 16 2025 15h 59m 23s -05° 22’ 13” 22.80 Libra
Jul 17 2025 15h 59m 11s -05° 22’ 21” 22.80 Libra
Jul 18 2025 15h 58m 59s -05° 22’ 29” 22.81 Libra
Jul 19 2025 15h 58m 47s -05° 22’ 40” 22.81 Libra
Jul 20 2025 15h 58m 36s -05° 22’ 51” 22.81 Libra
Jul 21 2025 15h 58m 25s -05° 23’ 04” 22.82 Libra
Jul 22 2025 15h 58m 14s -05° 23’ 20” 22.82 Libra
Jul 23 2025 15h 58m 04s -05° 23’ 35” 22.83 Libra

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