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Comet C/2023 H2 (Lemmon)

Below the horizon.  Never rises today
Alt: -50.60°   Az: 174.98°   Direction: South

Comet C/2023 H2 (Lemmon) is in the constellation of Octans, at a distance of 955,499,124.0 kilometers from Earth. The current Right Ascension is 00h 56m 53s and the Declination is -86° 43’ 39” (apparent coordinates). The predicted magnitude of Comet C/2023 H2 (Lemmon) is 24.70 (data provided by JPL Horizons).

Finder Charts

Map showing Comet C/2023 H2 (Lemmon) in Octans on May, 23 2025. Field of view: 50x30 degrees
View interactive star map
Sky map showing Comet C/2023 H2 (Lemmon) in Octans on May, 23 2025. Field of view: 15x9 degrees. View in interactive sky chart

High precision deep sky finder chart, 60 arcmin wide, showing where Comet C/2023 H2 (Lemmon) is right now. Click on the image to see a more detailed fullscreen tracker view.

C/2023 H2 (Lemmon)
RA: 00h 58m 05s
Dec: -86° 51’ 52”
Deep sky finder chart for Comet C/2023 H2 (Lemmon). Field of view: 60x40 arcmins. View in deep sky object tracker

Also check out Where is Comet C/2023 H2 (Lemmon)?, a page that provides all the information needed to find Comet C/2023 H2 (Lemmon) in the sky and additional links to sky charts.

Celestial Coordinates

Apparent

00h 56m 53s
-86° 43’ 39”
18h 54m 14s
19h 51m 08s

J2000

00h 58m 05s
-86° 51’ 52”

Additional Information

Octans
n/a
n/a
n/a
n/a
24.70

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

Today Comet C/2023 H2 (Lemmon) is not visible from Greenwich, UK

  • C/2023 H2 (Lemmon) is below the horizon from Greenwich, UK.
  • Given its current magnitude, C/2023 H2 (Lemmon) 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 C/2023 H2 (Lemmon) from Earth is currently 955,499,124.0 kilometers, equivalent to 6.3871171396 Astronomical Units. Light takes 53m 7.202s to travel from Comet C/2023 H2 (Lemmon) and arrive to us.

955,499,124.0
6.3871171396
53m 7.202s

The following chart shows the distance of Comet C/2023 H2 (Lemmon) 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/2023 H2 (Lemmon) 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/2023 H2 (Lemmon) 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 C/2023 H2 (Lemmon) to Earth happens on Sat Nov 11 2023 at a distance of 0.193049 Astronomical Units, or 28,879,775 kilometers:

Sat Nov 11 2023
28,879,775
0.193049

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 C/2023 H2 (Lemmon), 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/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 06 October 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 2023-Oct-29 04:33:37
2,460,246.6900 JD
Next perihelion transit 5754-Nov-01 20:50
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
2h1>Orbit Visualization
Orbit Diagram of Comet C/2023 H2 (Lemmon)
View Comet C/2023 H2 (Lemmon) in the 3D Solar System Simulator

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
2025 May 16 00h 24m 16s -85° 39’ 58” 24.67 Octans
2025 May 17 00h 28m 08s -85° 48’ 50” 24.67 Octans
2025 May 18 00h 32m 11s -85° 57’ 43” 24.67 Octans
2025 May 19 00h 36m 27s -86° 06’ 37” 24.68 Octans
2025 May 20 00h 40m 55s -86° 15’ 32” 24.68 Octans
2025 May 21 00h 45m 40s -86° 24’ 27” 24.69 Octans
2025 May 22 00h 50m 40s -86° 33’ 22” 24.69 Octans
2025 May 23 00h 56m 01s -86° 42’ 15” 24.70 Octans
2025 May 24 01h 01m 43s -86° 51’ 08” 24.70 Octans
2025 May 25 01h 07m 51s -86° 59’ 59” 24.70 Octans
2025 May 26 01h 14m 28s -87° 08’ 46” 24.71 Octans
2025 May 27 01h 21m 38s -87° 17’ 31” 24.71 Octans
2025 May 28 01h 29m 27s -87° 26’ 11” 24.72 Octans
2025 May 29 01h 38m 03s -87° 34’ 45” 24.72 Octans

Additional Resources on TheSkyLive