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public Observing fromLocation: Greenwich, United Kingdom edit_location_alt
north SunriseRise: 4:44  
clear_day Transit: 12:57  
SunsetSet: 21:11 south
wb_twilight Nautical TwilightWhat's Visible Now
Comets » 

Comet 17P/Holmes

Altitude: -17.7°   Azimuth: 338.0°   Direction: North-North-West

Comet 17P/Holmes is currently in the constellation of Cancer. The current Right Ascension of Comet 17P/Holmes is 09h 01m 35s and the Declination is +18° 11’ 40” (topocentric coordinates computed for the selected location: Greenwich, United Kingdom edit_location_alt). The current estimated magnitude of Comet 17P/Holmes is 22.99 (JPL).

09h 01m 35s
+18° 11’ 40”

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.

Today's rise, transit and set times of Comet 17P/Holmes from Greenwich, United Kingdom edit_location_alt (all times relative to the local timezone Europe/London):

Azimuth: 71.8°
Max altitude: 56.7°
Azimuth: 288.1°
  • 17P/Holmes is below the horizon from Greenwich, United Kingdom edit_location_alt.
  • Given its current magnitude, 17P/Holmes 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.

Available Resources

Comet 17P/Holmes Position and Finder Charts

Below we provide Comet 17P/Holmes 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.

Finder chart of 17P/Holmes in Cancer on June,08 2023
Map showing Comet 17P/Holmes in Cancer on June, 08 2023
Field of view: 50x30 degrees
View fullscreen
Finder chart of 17P/Holmes
Map showing Comet 17P/Holmes in Cancer on June, 08 2023
Field of view: 10x6 degrees
View fullscreen

Higher precision deep sky finder chart, 60 arcmin wide, showing where Comet 17P/Holmes is right now. Click on the image to see a more detailed fullscreen tracker view.

RA: 09h 01m 35s
Dec: +18° 11’ 40”
Deep sky finder chart for Comet 17P/Holmes
Field of view: 60x40 arcmins
View fullscreen

Also check out Where is Comet 17P/Holmes?, a page that provides all the information needed to find Comet 17P/Holmes in the sky and additional links to sky charts.

Comet 17P/Holmes Distance from Earth

The distance of Comet 17P/Holmes from Earth is currently 785,838,509 kilometers, equivalent to 5.253006 Astronomical Units. Light takes 43 minutes and 41.2751 seconds to travel from Comet 17P/Holmes and arrive to us.

43 minutes and 41.2751 seconds

The following chart shows the distance of Comet 17P/Holmes 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 17P/Holmes 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 17P/Holmes from Earth is also available as a real time updated value in the Live Position and Data Tracker.

Closest Approach of Comet 17P/Holmes to Earth

Between 1 January 2013 and 30 December 2100, the closest approach of Comet 17P/Holmes to Earth happens on Thu Aug 20 2048 at a distance of 1.146027 Astronomical Units, or 171,443,241 kilometers:

Thu Aug 20 2048

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

Comet 17P/Holmes Brightness and Light Curve

The following chart is the predicted light curve (visual magnitude as a function of time) of Comet 17P/Holmes, 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 17P/Holmes as a function of time

Comet 17P/Holmes Orbital Elements

The following table lists the orbital elements of Comet 17P/Holmes at epoch 18 October 2016 00:00 UTC (JD: 2457680.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.43015483
Orbit inclination i 19.07035900°
Perihelion distance q 2.06632924 AU
309,118,456 km
Aphelion distance Q 5.18591871 AU
775,802,399 km
Semi-major axis a 3.62612398 AU
542,460,427 km
Orbital period period 6.9051 years
2,522.1006 days
Date of perihelion transit Tp 2014-Mar-26 17:17:14
2,456,743.2203 JD
Next perihelion transit 2021-Feb-19 19:42
2,459,265.3209 JD
Argument of perihelion peri 24.738508616339°
Longitude of the ascending node node 326.77380841211°
Mean anomaly M 133.78558112051°
Mean motion n 0.14273816°/day

Visualization of Comet 17P/Holmes Orbit

This 3d orbit diagram is a feature of our 3D Solar System Simulator and shows the orbit of Comet 17P/Holmes with respect of the Sun and the orbits of the major planets. The position of Comet 17P/Holmes 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 17P/Holmes
View Comet 17P/Holmes in the 3D Solar System Simulator

Comet 17P/Holmes 15 Days Ephemeris

The following table lists the ephemerides of Comet 17P/Holmes computed for the past and next 7 days, with a 24 hours interval. Click on each row of the table to locate Comet 17P/Holmes in our Online Planetarium at the chosen date.

Date Right AscensionR.A. DeclinationDec. MagnitudeMag Constellation
2023 Jun 01 08h 57m 05s +18° 41’ 49” 22.93 Cancer
2023 Jun 02 08h 57m 42s +18° 37’ 40” 22.94 Cancer
2023 Jun 03 08h 58m 18s +18° 33’ 29” 22.95 Cancer
2023 Jun 04 08h 58m 56s +18° 29’ 16” 22.96 Cancer
2023 Jun 05 08h 59m 35s +18° 25’ 00” 22.97 Cancer
2023 Jun 06 09h 00m 12s +18° 20’ 44” 22.97 Cancer
2023 Jun 07 09h 00m 51s +18° 16’ 27” 22.98 Cancer
2023 Jun 08 09h 01m 31s +18° 12’ 09” 22.99 Cancer
2023 Jun 09 09h 02m 11s +18° 07’ 47” 23.00 Cancer
2023 Jun 10 09h 02m 50s +18° 03’ 25” 23.01 Cancer
2023 Jun 11 09h 03m 30s +17° 59’ 03” 23.02 Cancer
2023 Jun 12 09h 04m 12s +17° 54’ 38” 23.03 Cancer
2023 Jun 13 09h 04m 51s +17° 50’ 11” 23.04 Cancer
2023 Jun 14 09h 05m 34s +17° 45’ 43” 23.05 Cancer