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public  Mainling, China Mainling, China  ⓘ
TimezoneAsia/Urumqi
Sunrise: 4:49 
Transit: 11:47 
Sunset: 18:45
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Comets » 

Comet C/2023 H5 (Lemmon)

Above the horizon.  Circumpolar today
Alt: 32.69°   Az: 329.88°   Direction: North-North-West

Comet C/2023 H5 (Lemmon) is in the constellation of Ursa Major, at a distance of 714,375,483.0 kilometers from Earth. The current Right Ascension is 10h 59m 44s and the Declination is +64° 01’ 29” (apparent coordinates). The latest observed magnitude of comet C/2023 H5 (Lemmon) is 16.5 (data provided by COBS).

Finder Charts

The sky charts below show, at different resolutions, the position of comet C/2023 H5 (Lemmon) in the sky. Click on each chart to access the interactive star map tool.

Star map showing the position of comet C/2023 H5 (Lemmon) in the constellation of Ursa Major on F, d Y. Field of view: 50x30 degrees. View interactive star map.
Star map showing the position of comet C/2023 H5 (Lemmon) in the constellation of Ursa Major 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 H5 (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 H5 (Lemmon)
RA: 10h 58m 07s
Dec: +64° 09’ 42”
Simplified high-resolution deep sky chart showing the current position of comet C/2023 H5 (Lemmon). Field of view: 60 x 40 arcminutes. Go to the dedicated page

Equatorial Coordinates

Apparent

10h 59m 44s
+64° 01’ 29”
04h 58m 35s
15h 58m 19s

J2000

10h 58m 07s
+64° 09’ 42”

Additional Information

Ursa Major
16.5
0.8'
1.4'
2025-06-29
16.71

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 H5 (Lemmon) from Mainling, China (all times relative to the local timezone Asia/Urumqi):

Today comet C/2023 H5 (Lemmon) is circumpolar and transits at 09:56 UTC reaching a maximum altitude of 55.2°.

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 H5 (Lemmon) from Earth is currently 714,375,483.0 kilometers, equivalent to 4.7753051541 Astronomical Units. Light takes 39m 42.900s to travel from comet C/2023 H5 (Lemmon) and arrive to us.

714,375,483.0
4.7753051541
39m 42.900s

The following graph shows the distance of comet C/2023 H5 (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 H5 (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 H5 (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 H5 (Lemmon) to Earth happened on Saturday 22 February 2025 at a distance of 3.738543 Astronomical Units, or 559,278,089 kilometers:

Saturday 22 February 2025
559,278,089
3.738543

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 H5 (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 H5 (Lemmon) as a function of time

Orbital Elements

The following table lists the orbital elements of comet C/2023 H5 (Lemmon) at epoch September, 04 2024 00:00 UTC (JD: 2460558.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 1.00038807
Orbit inclination i 97.86088989°
Perihelion distance q 4.31283269 AU
645,190,588 km
Aphelion distance Q n.a.
Semi-major axis a n.a.
Orbital period period n.a.
Date of perihelion transit Tp June 30, 2025
2,460,856.6752 JD
Argument of perihelion peri 60.082903930745°
Longitude of the ascending node node 159.48174964041°
Mean anomaly M -0.00025084129973455°
Mean motion n 0.00000084°/day

Orbit Visualization

The following chart is a 3D animated visualization of the orbit of comet C/2023 H5 (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 H5 (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
Jun 26 2025 10h 52m 26s +64° 17’ 05” 16.69 Ursa Major
Jun 27 2025 10h 53m 18s +64° 14’ 59” 16.69 Ursa Major
Jun 28 2025 10h 54m 13s +64° 12’ 54” 16.70 Ursa Major
Jun 29 2025 10h 55m 09s +64° 10’ 49” 16.70 Ursa Major
Jun 30 2025 10h 56m 06s +64° 08’ 46” 16.70 Ursa Major
Jul 01 2025 10h 57m 05s +64° 06’ 44” 16.70 Ursa Major
Jul 02 2025 10h 58m 05s +64° 04’ 42” 16.70 Ursa Major
Jul 03 2025 10h 59m 05s +64° 02’ 43” 16.71 Ursa Major
Jul 04 2025 11h 00m 08s +64° 00’ 44” 16.71 Ursa Major
Jul 05 2025 11h 01m 12s +63° 58’ 47” 16.71 Ursa Major
Jul 06 2025 11h 02m 16s +63° 56’ 51” 16.71 Ursa Major
Jul 07 2025 11h 03m 22s +63° 54’ 56” 16.71 Ursa Major
Jul 08 2025 11h 04m 30s +63° 53’ 03” 16.72 Ursa Major
Jul 09 2025 11h 05m 38s +63° 51’ 11” 16.72 Ursa Major

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