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Comets » 

Comet C/2023 H2 (Lemmon)

Below the horizon.  Never rises today
Alt: -57.40°   Az: 179.02°   Direction: South

Comet C/2023 H2 (Lemmon) is in the constellation of Octans, at a distance of 1,025,146,872.0 kilometers from Earth. The current Right Ascension is 12h 13m 02s and the Declination is -84° 03’ 26” (apparent coordinates). The estimated magnitude of comet C/2023 H2 (Lemmon), computed using JPL Horizons's data, is 25.01.

Finder Charts

The sky charts below show, at different resolutions, the position of comet C/2023 H2 (Lemmon) in the sky. Click on each chart to access the interactive star map tool.

Star map showing the position of comet C/2023 H2 (Lemmon) in the constellation of Octans on F, d Y. Field of view: 50x30 degrees. View interactive star map.
Star map showing the position of comet C/2023 H2 (Lemmon) in the constellation of Octans 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/2023 H2 (Lemmon) 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/2023 H2 (Lemmon)
RA: 12h 11m 27s
Dec: -83° 54’ 54”
Simplified high-resolution deep sky chart showing the current position of comet C/2023 H2 (Lemmon). Field of view: 60 x 40 arcminutes. Go to the dedicated page

Equatorial Coordinates

Apparent

12h 13m 02s
-84° 03’ 26”
12h 20m 28s
00h 33m 31s

J2000

12h 11m 27s
-83° 54’ 54”

Additional Information

Octans
n/a
n/a
n/a
n/a
25.01

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/2023 H2 (Lemmon) from Greenwich, UK (all times relative to the local timezone Europe/London):

Greenwich, UKToday comet C/2023 H2 (Lemmon) is not visible from

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/2023 H2 (Lemmon) from Earth is currently 1,025,146,872.0 kilometers, equivalent to 6.8526835790 Astronomical Units. Light takes 56m 59.522s to travel from comet C/2023 H2 (Lemmon) and arrive to us.

1,025,146,872.0
6.8526835790
56m 59.522s

The following graph shows the distance of comet C/2023 H2 (Lemmon) 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/2023 H2 (Lemmon) 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/2023 H2 (Lemmon) 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/2023 H2 (Lemmon) to Earth happened on Saturday 11 November 2023 at a distance of 0.193049 Astronomical Units, or 28,879,775 kilometers:

Saturday 11 November 2023
28,879,775
0.193049

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/2023 H2 (Lemmon), 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/2023 H2 (Lemmon) as a function of time

Orbital Elements

The following table lists the orbital elements of comet C/2023 H2 (Lemmon) at epoch October, 06 2023 00:00 UTC (JD: 2460224.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.99628184
Orbit inclination i 113.75348343°
Perihelion distance q 0.89440522 AU
133,801,116 km
Aphelion distance Q 480.20657957 AU
71,837,881,944 km
Semi-major axis a 240.55049240 AU
35,985,841,530 km
Orbital period period 3,730.9341 years
1,362,723.6784 days
Date of perihelion transit Tp October 29, 2023
2,460,246.6900 JD
Next perihelion transit November 1, 5754
3,822,970.3684 JD
Argument of perihelion peri 150.65034885899°
Longitude of the ascending node node 217.04480550749°
Mean anomaly M 359.99413791105°
Mean motion n 0.00026418°/day

Orbit Visualization

The following chart is a 3D animated visualization of the orbit of comet C/2023 H2 (Lemmon) 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/2023 H2 (Lemmon) 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 11h 51m 44s -85° 07’ 51” 24.96 Octans
Jul 11 2025 11h 54m 59s -84° 58’ 50” 24.97 Octans
Jul 12 2025 11h 58m 07s -84° 49’ 48” 24.97 Octans
Jul 13 2025 12h 01m 09s -84° 40’ 49” 24.98 Octans
Jul 14 2025 12h 04m 06s -84° 31’ 52” 24.99 Octans
Jul 15 2025 12h 06m 58s -84° 22’ 57” 24.99 Octans
Jul 16 2025 12h 09m 46s -84° 14’ 03” 25.00 Octans
Jul 17 2025 12h 12m 30s -84° 05’ 13” 25.01 Octans
Jul 18 2025 12h 15m 09s -83° 56’ 25” 25.01 Octans
Jul 19 2025 12h 17m 45s -83° 47’ 39” 25.02 Octans
Jul 20 2025 12h 20m 18s -83° 38’ 57” 25.03 Octans
Jul 21 2025 12h 22m 47s -83° 30’ 17” 25.04 Octans
Jul 22 2025 12h 25m 15s -83° 21’ 40” 25.04 Octans
Jul 23 2025 12h 27m 39s -83° 13’ 06” 25.05 Chamaleon

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