Find it in the Sky
Chose a date & time and view the position of comet 123P/West-Hartley in the sky on our interactive planetarium.
In Evidence
Comet 123P/West-Hartley
Comet 123P/West-Hartley is in the constellation of Taurus, at a distance of
Finder Charts
The sky charts below show, at different resolutions, the position of comet 123P/West-Hartley in the sky. Click on each chart to access the interactive star map tool.
The following map uses photographic imagery from the Digitized Sky Survey (DSS) to realistically visualize the precise position of comet 123P/West-Hartley 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.
Equatorial Coordinates
Apparent
J2000
Additional Information
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 123P/West-Hartley from Medenine, Tunisia (all times relative to the local timezone Africa/Tunis):
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
The following graph shows the distance of comet 123P/West-Hartley 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.
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 123P/West-Hartley 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 123P/West-Hartley to Earth happened on Thursday 28 February 2019 at a distance of 1.199581 Astronomical Units, or 179,454,775 kilometers:
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 123P/West-Hartley, 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.
Orbital Elements
The following table lists the orbital elements of comet 123P/West-Hartley at epoch September, 18 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 | February 4, 2019 2,458,518.8399 JD |
| Next perihelion transit | September 5, 2026 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 |
Orbit Visualization
The following chart is a 3D animated visualization of the orbit of comet 123P/West-Hartley 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 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 |
|---|---|---|---|---|
| Jul 05 2025 | 03h 24m 42s | +17° 22’ 23” | 21.47 | Aries |
| Jul 06 2025 | 03h 25m 45s | +17° 27’ 52” | 21.45 | Taurus |
| Jul 07 2025 | 03h 26m 48s | +17° 33’ 19” | 21.44 | Taurus |
| Jul 08 2025 | 03h 27m 51s | +17° 38’ 45” | 21.42 | Taurus |
| Jul 09 2025 | 03h 28m 53s | +17° 44’ 09” | 21.40 | Taurus |
| Jul 10 2025 | 03h 29m 55s | +17° 49’ 33” | 21.39 | Taurus |
| Jul 11 2025 | 03h 30m 56s | +17° 54’ 54” | 21.37 | Taurus |
| Jul 12 2025 | 03h 31m 58s | +18° 00’ 13” | 21.35 | Taurus |
| Jul 13 2025 | 03h 32m 59s | +18° 05’ 31” | 21.33 | Taurus |
| Jul 14 2025 | 03h 34m 00s | +18° 10’ 47” | 21.32 | Taurus |
| Jul 15 2025 | 03h 35m 01s | +18° 16’ 01” | 21.30 | Taurus |
| Jul 16 2025 | 03h 36m 01s | +18° 21’ 15” | 21.28 | Taurus |
| Jul 17 2025 | 03h 37m 01s | +18° 26’ 27” | 21.26 | Taurus |
| Jul 18 2025 | 03h 38m 01s | +18° 31’ 37” | 21.25 | Taurus |
Additional Resources on TheSkyLive
- Comet 123P/West-Hartley: Complete reference information on TheSkyLive.com.
- Where is comet 123P/West-Hartley?: Key information on where to find comet 123P/West-Hartley in the sky.
- Distance of comet 123P/West-Hartley from Earth: Find out how far comet 123P/West-Hartley is from Earth right now.
- How Bright is comet 123P/West-Hartley?: Current visual brightness (magnitude) and apparent size.
- Rise and Set Times: Rise and set times of comet 123P/West-Hartley from your location.
- Interactive Sky Map: Planetarium-style interactive visualization of comet 123P/West-Hartley's position in the sky.
- Live Position Tracker: High precision real time tracker of comet 123P/West-Hartley's position using deep space imagery.
- Ephemeris: 15 days comet 123P/West-Hartley's computed ephemeris.
- Orbital elements: Information about comet 123P/West-Hartley orbital parameters.
- Orbit Visualization: 3D interactive visualization showing the orbit of comet 123P/West-Hartley with respect to the major Solar System objects.