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Comet 123P/West-Hartley

Above the horizon.  Rise: 4:51 | Tran: 11:53 | Set: 18:54
Alt: 40.01°   Az: 127.51°   Direction: South-East

Comet 123P/West-Hartley is in the constellation of Aries, at a distance of 720,274,324.0 kilometers from Earth. The current Right Ascension is 02h 30m 44s and the Declination is +12° 16’ 42” (apparent coordinates). The predicted magnitude of Comet 123P/West-Hartley is 22.17 (data provided by JPL Horizons).

Finder Charts

Map showing Comet 123P/West-Hartley in Aries on May, 16 2025. Field of view: 50x30 degrees
View interactive star map
Sky map showing Comet 123P/West-Hartley in Aries on May, 16 2025. Field of view: 15x9 degrees. View in interactive sky chart

High precision deep sky finder chart, 60 arcmin wide, showing where Comet 123P/West-Hartley is right now. Click on the image to see a more detailed fullscreen tracker view.

123P/West-Hartley
RA: 02h 29m 21s
Dec: +12° 09’ 58”
Deep sky finder chart for Comet 123P/West-Hartley. Field of view: 60x40 arcmins. View in deep sky object tracker

Also check out Where is Comet 123P/West-Hartley?, a page that provides all the information needed to find Comet 123P/West-Hartley in the sky and additional links to sky charts.

Celestial Coordinates

Apparent

02h 30m 44s
+12° 16’ 42”
21h 26m 12s
23h 56m 56s

J2000

02h 29m 21s
+12° 09’ 58”

Additional Information

Aries
n/a
n/a
n/a
n/a
22.17

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 123P/West-Hartley from Greenwich, UK (all times relative to the local timezone Europe/London):

Azimuth: 77.7°
Max altitude: 50.8°
Azimuth: 282.3°
  • 123P/West-Hartley is above the horizon from Greenwich, UK.
  • Right now it is placed in the South-East direction at an altitude of 40.01° above the horizon.
  • Given its current magnitude, 123P/West-Hartley 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 123P/West-Hartley from Earth is currently 720,274,324.0 kilometers, equivalent to 4.8147364707 Astronomical Units. Light takes 40m 2.577s to travel from Comet 123P/West-Hartley and arrive to us.

720,274,324.0
4.8147364707
40m 2.577s

The following chart shows the distance of Comet 123P/West-Hartley 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 123P/West-Hartley 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 123P/West-Hartley 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 123P/West-Hartley to Earth happens on Thu Feb 28 2019 at a distance of 1.199581 Astronomical Units, or 179,454,775 kilometers:

Thu Feb 28 2019
179,454,775
1.199581

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 123P/West-Hartley, 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 123P/West-Hartley as a function of time

Orbital Elements

The following table lists the orbital elements of Comet 123P/West-Hartley at epoch 18 September 2015 00:00 UTC (JD: 2457284.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.44927022
Orbit inclination i 15.35454558°
Perihelion distance q 2.12610687 AU
318,061,062 km
Aphelion distance Q 5.59494602 AU
836,992,012 km
Semi-major axis a 3.86052645 AU
577,526,537 km
Orbital period period 7.5854 years
2,770.5642 days
Date of perihelion transit Tp 2019-Feb-04 08:09:24
2,458,518.8399 JD
Next perihelion transit 2026-Sep-05 21:41
2,461,289.4041 JD
Argument of perihelion peri 102.91844683507°
Longitude of the ascending node node 46.527373044969°
Mean anomaly M 199.61304892378°
Mean motion n 0.12993743°/day
2h1>Orbit Visualization
Orbit Diagram of Comet 123P/West-Hartley
View Comet 123P/West-Hartley in the 3D Solar System Simulator

15 Days Ephemeris

The following table lists the ephemerides of Comet 123P/West-Hartley 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 09 02h 22m 45s +11° 26’ 37” 22.25 Aries
2025 May 10 02h 23m 50s +11° 33’ 30” 22.24 Aries
2025 May 11 02h 24m 55s +11° 40’ 21” 22.23 Aries
2025 May 12 02h 26m 00s +11° 47’ 11” 22.21 Aries
2025 May 13 02h 27m 06s +11° 54’ 00” 22.20 Aries
2025 May 14 02h 28m 11s +12° 00’ 48” 22.19 Aries
2025 May 15 02h 29m 16s +12° 07’ 36” 22.18 Aries
2025 May 16 02h 30m 21s +12° 14’ 21” 22.17 Aries
2025 May 17 02h 31m 27s +12° 21’ 06” 22.16 Aries
2025 May 18 02h 32m 32s +12° 27’ 48” 22.15 Aries
2025 May 19 02h 33m 38s +12° 34’ 31” 22.13 Aries
2025 May 20 02h 34m 43s +12° 41’ 11” 22.12 Aries
2025 May 21 02h 35m 49s +12° 47’ 52” 22.11 Aries
2025 May 22 02h 36m 55s +12° 54’ 30” 22.10 Aries

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