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Comet 21P/Giacobini-Zinner

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Comet 21P/Giacobini-Zinner Position

Comet 21P/Giacobini-Zinner is currently in the constellation of Crater. The current Right Ascension is 10h 57m 34s and the Declination is -17° 29’ 52”.

10h 57m 34s
-17° 29’ 52”

Simplified sky chart showing where Comet 21P/Giacobini-Zinner is right now in the sky with respect to the brightest stars and constellations (see full screen Online Planetarium)

Map showing Comet 21P/Giacobini-Zinner in Crater on January, 20 2020
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]

Higher precision deep sky finder chart showing where Comet 21P/Giacobini-Zinner is right now (view fullscreen)

RA: 10h 57m 34s
Dec: -17° 29’ 52”
Deep sky finder chart for Comet 21P/Giacobini-Zinner
Field of view: 60x40 arcmins
View fullscreen

Also check out Where is Comet 21P/Giacobini-Zinner?, a page that provides all the information needed to find Comet 21P/Giacobini-Zinner in the sky and additional links to sky charts.

Comet 21P/Giacobini-Zinner Distance

The distance of Comet 21P/Giacobini-Zinner from Earth is currently 573,054,436 kilometers, equivalent to 3.830632 Astronomical Units. Light takes 31 minutes and 51.5038 seconds to travel from Comet 21P/Giacobini-Zinner and arrive to us.

31 minutes and 51.5038 seconds

The following chart shows the distance of Comet 21P/Giacobini-Zinner 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 21P/Giacobini-Zinner 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 21P/Giacobini-Zinner from Earth is also available as a real time updated value in the Live Position and Data Tracker.

Closest approach of Comet 21P/Giacobini-Zinner to Earth

Between January 2013 and December 2100 the closest approach of Comet 21P/Giacobini-Zinner to Earth happens on Tue Sep 17 2058 at a distance of 0.39032355 Astronomical Units, or 58,391,572 kilometers:

Tue Sep 17 2058

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

Comet 21P/Giacobini-Zinner brightness

The current visual magnitude of Comet 21P/Giacobini-Zinner is 21.85.


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 21P/Giacobini-Zinner, 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 21P/Giacobini-Zinner between January 2013 and December 2100

Comet 21P/Giacobini-Zinner 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 21P/Giacobini-Zinner rise, transit and set times from Greenwich, United Kingdom [change] are the following (all times relative to the local timezone Europe/London):

Azimuth: 107.5°
Max altitude: 21.0°
Azimuth: 252.5°
Comet 21P/Giacobini-Zinner is above the horizon from Greenwich, United Kingdom

The rise and set times are defined as the time at which the upper limb of Comet 21P/Giacobini-Zinner 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 21P/Giacobini-Zinner Orbital Elements

The following table lists the orbital elements of Comet 21P/Giacobini-Zinner at epoch 08 August 2018 00:00 UTC (JD: 2458339.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.71046355
Orbit inclination i 31.99782626°
Perihelion distance q 1.01282554 AU
151,516,544 km
Aphelion distance Q 5.98336123 AU
895,098,101 km
Semi-major axis a 3.49809338 AU
523,307,323 km
Orbital period period 6.5400 years
2,389.7118 days
Date of perihelion transit Tp 2018-Sep-10 06:39:39
2,458,371.7775 JD
Next perihelion transit 2025-Mar-26 23:44
2,460,761.4893 JD
Argument of perihelion peri 172.86055325826°
Longitude of the ascending node node 195.39198746422°
Mean anomaly M 355.13752392339°
Mean motion n 0.15064578°/day

Visualization of Comet 21P/Giacobini-Zinner Orbit

This 3d orbit diagram is a feature of our 3D Solar System Simulator and shows the orbit of Comet 21P/Giacobini-Zinner with respect of the Sun and the orbits of the major planets. The position of Comet 21P/Giacobini-Zinner 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 21P/Giacobini-Zinner
View Comet 21P/Giacobini-Zinner in the 3D Solar System Simulator

Comet 21P/Giacobini-Zinner 15 Days Ephemeris

The following table lists the ephemerides of Comet 21P/Giacobini-Zinner computed for the past and next 7 days, with a 24 hours interval. Click on each row of the table to locate Comet 21P/Giacobini-Zinner in our Online Planetarium at the chosen date.

Date Right AscensionR.A. DeclinationDec. MagnitudeMag Constellation
2020 Jan 13 11h 00m 24s -17° 29’ 21” 21.85 Crater
2020 Jan 14 11h 00m 02s -17° 29’ 50” 21.85 Crater
2020 Jan 15 10h 59m 39s -17° 30’ 12” 21.85 Crater
2020 Jan 16 10h 59m 17s -17° 30’ 27” 21.85 Crater
2020 Jan 17 10h 58m 53s -17° 30’ 32” 21.85 Crater
2020 Jan 18 10h 58m 27s -17° 30’ 28” 21.85 Crater
2020 Jan 19 10h 58m 01s -17° 30’ 15” 21.85 Crater
2020 Jan 20 10h 57m 34s -17° 29’ 53” 21.85 Crater
2020 Jan 21 10h 57m 06s -17° 29’ 21” 21.85 Crater
2020 Jan 22 10h 56m 39s -17° 28’ 41” 21.85 Crater
2020 Jan 23 10h 56m 09s -17° 27’ 52” 21.85 Crater
2020 Jan 24 10h 55m 40s -17° 26’ 53” 21.85 Crater
2020 Jan 25 10h 55m 09s -17° 25’ 45” 21.85 Crater
2020 Jan 26 10h 54m 37s -17° 24’ 28” 21.85 Crater