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🌎 Location: Greenwich, United Kingdom [change]

Comet 123P/West-Hartley

Comet 123P/West-Hartley is currently in the constellation of Sagittarius. The current Right Ascension of Comet 123P/West-Hartley is 19h 35m 44s and the Declination is -32° 56’ 14” (topocentric coordinates computed for the selected location: Greenwich, United Kingdom [change]). The current estimated magnitude of Comet 123P/West-Hartley is 23.92 (JPL).

Summary of key facts about Comet 123P/West-Hartley [tip: you can also create a Quick Access page for this data if you access it frequently and would like to have a simpler view]:

19h 35m 44s
-32° 56’ 14”

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Additional information about Comet 123P/West-Hartley available on TheSkyLive:

Available Resources

Comet 123P/West-Hartley Position and Finder Charts

Below we provide Comet 123P/West-Hartley finder charts showing where the object is right now in the sky with respect to the brightest stars. The first finder chart has a field of view of 50 degrees, while the second one has a field of view of 10 degrees. Click on each finder chart to access a full screen interactive Online Planetarium.

Map showing Comet 123P/West-Hartley in Sagittarius on January, 25 2021
Field of view: 50x30 degrees
View fullscreen
Map showing Comet 123P/West-Hartley in Sagittarius on January, 25 2021
Field of view: 10x6 degrees
View fullscreen
 = visible to the naked eye
 = binocular, brighter than 10th magnitude
= current altitude ≥ 30°   = current altitude < 30°   = below the horizon
Location: Greenwich, United Kingdom [change]

Higher 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.

RA: 19h 35m 44s
Dec: -32° 56’ 14”
Deep sky finder chart for Comet 123P/West-Hartley
Field of view: 60x40 arcmins
View fullscreen

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.

Comet 123P/West-Hartley Distance from Earth

The distance of Comet 123P/West-Hartley from Earth is currently 831,446,003 kilometers, equivalent to 5.557873 Astronomical Units. Light takes 46 minutes and 13.4053 seconds to travel from Comet 123P/West-Hartley and arrive to us.

46 minutes and 13.4053 seconds

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.

Distance of Comet 123P/West-Hartley from Earth between January 2013 and December 2100

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 of Comet 123P/West-Hartley to Earth

Between January 2013 and December 2100, the closest approach of Comet 123P/West-Hartley to Earth happens on Thu Feb 28 2019 at a distance of 1.199580 Astronomical Units, or 179,454,681 kilometers:

Thu Feb 28 2019

NOTE: values for the closest approach are computed with a sampling interval of 1 day.

Comet 123P/West-Hartley brightness

The current visual magnitude of Comet 123P/West-Hartley is 23.92.


The observed magnitude and coma diameter values are derived from the Comet Observers Database by averaging the values reported in recent observations (more recent than 4 days), when available. The Estimated Magnitude comes from the JPL Horizons ephemerides service and might be inaccurate given the highly dynamic and unpredictable behavior of comets. When available, please refer to the Observed Magnitude value and consider the Estimated 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.

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.

Predicted magnitude of Comet 123P/West-Hartley between January 2013 and December 2100

Comet 123P/West-Hartley rise and set times

Location: Greenwich, United Kingdom [change]
Latitude: 51° 28’ 47” N
Longitude: 0° 00’ 00” E
Timezone: Europe/London

Today's Comet 123P/West-Hartley rise, transit and set times from Greenwich, United Kingdom [change] are the following (all times relative to the local timezone Europe/London):

Azimuth: 122.9°
Max altitude: 5.6°
Azimuth: 237.1°

The rise and set times are defined as the time at which the upper limb of Comet 123P/West-Hartley touches the horizon, considering the effect of the atmospheric refraction. As the atmospheric conditions cannot be modeled precisely the times reported here should be considered correct with an approximation of few minutes.

Comet 123P/West-Hartley Orbital Elements

The following table lists the orbital elements of Comet 123P/West-Hartley at epoch 14 August 2015 00:00 UTC (JD: 2457249.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.44927079
Orbit inclination i 15.35434947°
Perihelion distance q 2.12611187 AU
318,061,810 km
Aphelion distance Q 5.59496720 AU
836,995,181 km
Semi-major axis a 3.86053953 AU
577,528,495 km
Orbital period period 7.5900 years
2,770.5783 days
Date of perihelion transit Tp 2019-Feb-04 07:24:14
2,458,518.8085 JD
Next perihelion transit 2026-Sep-05 21:17
2,461,289.3868 JD
Argument of perihelion peri 102.91440751036°
Longitude of the ascending node node 46.52937240701°
Mean anomaly M 195.07015237268°
Mean motion n 0.12993677°/day

Visualization of Comet 123P/West-Hartley Orbit

This 3d orbit diagram is a feature of our 3D Solar System Simulator and shows the orbit of Comet 123P/West-Hartley with respect of the Sun and the orbits of the major planets. The position of Comet 123P/West-Hartley and the planets along their orbits in this diagram accurately represents the current configuration of the objects in the Solar System. This is an experimental feature and it requires a WebGL enabled browser. Please provide us feedback!

Orbit Diagram of Comet 123P/West-Hartley
View Comet 123P/West-Hartley in the 3D Solar System Simulator

Comet 123P/West-Hartley 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. Click on each row of the table to locate Comet 123P/West-Hartley in our Online Planetarium at the chosen date.

Date Right AscensionR.A. DeclinationDec. MagnitudeMag Constellation
2021 Jan 18 19h 26m 58s -33° 06’ 06” 23.88 Sagittarius
2021 Jan 19 19h 28m 08s -33° 04’ 49” 23.89 Sagittarius
2021 Jan 20 19h 29m 17s -33° 03’ 30” 23.89 Sagittarius
2021 Jan 21 19h 30m 27s -33° 02’ 12” 23.90 Sagittarius
2021 Jan 22 19h 31m 36s -33° 00’ 55” 23.90 Sagittarius
2021 Jan 23 19h 32m 44s -32° 59’ 36” 23.91 Sagittarius
2021 Jan 24 19h 33m 54s -32° 58’ 19” 23.91 Sagittarius
2021 Jan 25 19h 35m 02s -32° 57’ 02” 23.91 Sagittarius
2021 Jan 26 19h 36m 10s -32° 55’ 45” 23.92 Sagittarius
2021 Jan 27 19h 37m 18s -32° 54’ 28” 23.92 Sagittarius
2021 Jan 28 19h 38m 26s -32° 53’ 11” 23.93 Sagittarius
2021 Jan 29 19h 39m 33s -32° 51’ 55” 23.93 Sagittarius
2021 Jan 30 19h 40m 41s -32° 50’ 39” 23.94 Sagittarius
2021 Jan 31 19h 41m 48s -32° 49’ 23” 23.94 Sagittarius