Your guide to the Solar System
🌎 Location: Greenwich, United Kingdom [change]
Comets » 

Comet 17P/Holmes

Available Resources

Comet 17P/Holmes Position

Comet 17P/Holmes is currently in the constellation of Hydra. The current Right Ascension is 13h 08m 01s and the Declination is -27° 30’ 16”.

13h 08m 01s
-27° 30’ 16”

Simplified sky chart showing where Comet 17P/Holmes is right now in the sky with respect to the brightest stars and constellations (see fuillscreen Online Planetarium)

Map showing Comet 17P/Holmes in Hydra on July, 24 2019
Field of view: 60x30 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]

Hihgher precision deep sky finder chart showing where Comet 17P/Holmes is right now (view fullscreen)

RA: 13h 08m 01s
Dec: -27° 30’ 16”
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

The distance of Comet 17P/Holmes from Earth is currently 598,209,173 kilometers, equivalent to 3.998781 Astronomical Units. Light takes 33 minutes and 15.4110 seconds to travel from Comet 17P/Holmes and arrive to us.

33 minutes and 15.4110 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.

Distance of Comet 17P/Holmes 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 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 January 2013 and December 2100 the closest approach of Comet 17P/Holmes to Earth happens on Thu Aug 20 2048 at a distance of 1.14521996 Astronomical Units, or 171,322,468 kilometers:

Thu Aug 20 2048

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

Comet 17P/Holmes brightness

The current visual magnitude of Comet 17P/Holmes is 21.03.


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 behvior 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 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.

Predicted magnitude of Comet 17P/Holmes between January 2013 and December 2100

Comet 17P/Holmes 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 17P/Holmes rise, transit and set times from Greenwich, United Kingdom [change] are the following (all times relative to the local timezone Europe/London):

Azimuth: 117.5°
Max altitude: 11.0°
Azimuth: 242.5°
Comet 17P/Holmes is below the horizon from Greenwich, United Kingdom

The rise and set times are defined as the time at which the upper limb of Comet 17P/Holmes touches the horizon, consideting the effect of the atmospheric refraction. As the atmoshpere conditions cannot be modeled precisely the times reported here should be considered correct with an approximation of few minutes.

Comet 17P/Holmes Orbital Elements

The following table lists the orbital elements of Comet 17P/Holmes at epoch 02 August 2014 00:00 UTC (JD: 2456872.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.43181344
Orbit inclination i 19.09175525°
Perihelion distance q 2.05661374 AU
307,665,038 km
Aphelion distance Q 5.18260623 AU
775,306,858 km
Semi-major axis a 3.61960999 AU
541,485,948 km
Orbital period period 6.8900 years
2,515.3075 days
Date of perihelion transit Tp 2014-Mar-27 12:18:11
2,456,744.0126 JD
Next perihelion transit 2021-Feb-13 19:41
2,459,259.3202 JD
Argument of perihelion peri 24.515349359396°
Longitude of the ascending node node 326.76479965817°
Mean anomaly M 18.389581859552°
Mean motion n 0.14312365°/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
2019 Jul 17 13h 04m 26s -27° 37’ 58” 21.03 Hydra
2019 Jul 18 13h 04m 54s -27° 36’ 34” 21.03 Hydra
2019 Jul 19 13h 05m 21s -27° 35’ 18” 21.03 Hydra
2019 Jul 20 13h 05m 52s -27° 34’ 08” 21.03 Hydra
2019 Jul 21 13h 06m 21s -27° 33’ 02” 21.03 Hydra
2019 Jul 22 13h 06m 52s -27° 32’ 03” 21.03 Hydra
2019 Jul 23 13h 07m 23s -27° 31’ 09” 21.03 Hydra
2019 Jul 24 13h 07m 57s -27° 30’ 23” 21.03 Hydra
2019 Jul 25 13h 08m 30s -27° 29’ 42” 21.03 Hydra
2019 Jul 26 13h 09m 05s -27° 29’ 05” 21.03 Hydra
2019 Jul 27 13h 09m 39s -27° 28’ 36” 21.03 Hydra
2019 Jul 28 13h 10m 14s -27° 28’ 11” 21.03 Hydra
2019 Jul 29 13h 10m 51s -27° 27’ 53” 21.03 Hydra
2019 Jul 30 13h 11m 29s -27° 27’ 42” 21.03 Hydra