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Comets » 

Comet Leonard (C/2021 A1)

Above the horizon.  Rise: 20:02 | Tran: 1:34 | Set: 7:01
Alt: 17.38°   Az: 235.22°   Direction: South-West

Comet Leonard (C/2021 A1) is in the constellation of Ophiuchus, at a distance of 1,655,850,938.0 kilometers from Earth. The current Right Ascension is 16h 17m 48s and the Declination is -06° 03’ 00” (apparent coordinates). The predicted magnitude of Comet Leonard (C/2021 A1) is 22.58 (data provided by JPL Horizons).

Finder Charts

Map showing Comet Leonard (C/2021 A1) in Ophiuchus on May, 18 2025. Field of view: 50x30 degrees
View interactive star map
Sky map showing Comet Leonard (C/2021 A1) in Ophiuchus on May, 18 2025. Field of view: 15x9 degrees. View in interactive sky chart

High precision deep sky finder chart, 60 arcmin wide, showing where Comet Leonard (C/2021 A1) is right now. Click on the image to see a more detailed fullscreen tracker view.

C/2021 A1 (Leonard)
RA: 16h 16m 27s
Dec: -05° 59’ 19”
Deep sky finder chart for Comet Leonard (C/2021 A1). Field of view: 60x40 arcmins. View in deep sky object tracker

Also check out Where is Comet Leonard (C/2021 A1)?, a page that provides all the information needed to find Comet Leonard (C/2021 A1) in the sky and additional links to sky charts.

Celestial Coordinates

Apparent

16h 17m 48s
-06° 03’ 00”
03h 28m 05s
19h 45m 53s

J2000

16h 16m 27s
-05° 59’ 19”

Additional Information

Ophiuchus
n/a
n/a
n/a
n/a
22.58

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

Today's rise, transit and set times of Comet Leonard (C/2021 A1) from Greenwich, UK (all times relative to the local timezone Europe/London):

Azimuth: 96.0°
Max altitude: 32.5°
Azimuth: 264.0°
  • C/2021 A1 (Leonard) is above the horizon from Greenwich, UK.
  • Right now it is placed in the South-West direction at an altitude of 17.38° above the horizon.
  • Given its current magnitude, C/2021 A1 (Leonard) 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.

Distance from Earth

The distance of Comet Leonard (C/2021 A1) from Earth is currently 1,655,850,938.0 kilometers, equivalent to 11.0686798566 Astronomical Units. Light takes 1h 32m 3.324s to travel from Comet Leonard (C/2021 A1) and arrive to us.

1,655,850,938.0
11.0686798566
1h 32m 3.324s

The following chart shows the distance of Comet Leonard (C/2021 A1) 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 Leonard (C/2021 A1) 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 A1 (Leonard) from Earth is also available as a real time updated value in the Live Position and Data Tracker.

Closest Approach

Between 1 January 2000 and 31 December 2099, the closest approach of Comet Leonard (C/2021 A1) to Earth happens on Mon Dec 13 2021 at a distance of 0.233994 Astronomical Units, or 35,005,003 kilometers:

Mon Dec 13 2021
35,005,003
0.233994

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

Light Curve

The following chart is the predicted light curve (visual magnitude as a function of time) of Comet Leonard (C/2021 A1), 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 Leonard (C/2021 A1) as a function of time

Orbital Elements

The following table lists the orbital elements of Comet Leonard (C/2021 A1) at epoch 10 July 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 2022-Jan-03 07:01:27
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
2h1>Orbit Visualization
Orbit Diagram of Comet Leonard (C/2021 A1)
View Comet Leonard (C/2021 A1) in the 3D Solar System Simulator

15 Days Ephemeris

The following table lists the ephemerides of Comet Leonard (C/2021 A1) 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
2025 May 11 16h 20m 23s -06° 13’ 59” 22.57 Ophiuchus
2025 May 12 16h 20m 02s -06° 12’ 23” 22.57 Ophiuchus
2025 May 13 16h 19m 40s -06° 10’ 49” 22.57 Ophiuchus
2025 May 14 16h 19m 19s -06° 09’ 16” 22.58 Ophiuchus
2025 May 15 16h 18m 57s -06° 07’ 44” 22.58 Ophiuchus
2025 May 16 16h 18m 35s -06° 06’ 12” 22.58 Ophiuchus
2025 May 17 16h 18m 14s -06° 04’ 43” 22.58 Ophiuchus
2025 May 18 16h 17m 52s -06° 03’ 15” 22.58 Ophiuchus
2025 May 19 16h 17m 30s -06° 01’ 47” 22.59 Ophiuchus
2025 May 20 16h 17m 08s -06° 00’ 22” 22.59 Ophiuchus
2025 May 21 16h 16m 46s -05° 58’ 57” 22.59 Ophiuchus
2025 May 22 16h 16m 24s -05° 57’ 34” 22.59 Ophiuchus
2025 May 23 16h 16m 02s -05° 56’ 12” 22.59 Ophiuchus
2025 May 24 16h 15m 40s -05° 54’ 52” 22.60 Ophiuchus

Additional Resources on TheSkyLive