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Comet 21P/Giacobini-Zinner

Available Resources

Comet 21P/Giacobini-Zinner Sky Charts and Coordinates

This is a simplified sky chart, showing where Comet 21P/Giacobini-Zinner is now with respect to the brightest stars and constellations.

More advanced sky charts are available on TheSkyLive for this object: 1) the Online Planetarium which is interactive and allows to select dates and additional objects to visualize; and 2) the Live Position and Data Tracker which provides the highest precision position data and features deep sky imagery from the Digitized Sky Survey.

Comet 21P/Giacobini-Zinner in Canis Majoris on October, 16 2018
High Precision Live Sky Chart
 = visible to the naked eye
 = binocular, brighter than 10th magnitude
= current altitude ≥ 30°   = current altitude < 30°   = below the horizon
Location: Greenwich, United Kingdom [change]
07h 15m 21s
-16° 45’ 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.

Comet 21P/Giacobini-Zinner Rise and Set Times

Today's Comet 21P/Giacobini-Zinner rise, transit and set times from Greenwich, United Kingdom [change]. All times are relative to the Europe/London timezone.

Azimuth: 106.5°
Max altitude: 21.8°
Azimuth: 253.1°

Comet 21P/Giacobini-Zinner Orbit Diagram

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 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
2018 Oct 09 07h 05m 53s -09° 35’ 48” 11.69 Monoceros
2018 Oct 10 07h 07m 23s -10° 39’ 51” 11.74 Monoceros
2018 Oct 11 07h 08m 48s -11° 42’ 10” 11.79 Canis Majoris
2018 Oct 12 07h 10m 09s -12° 42’ 50” 11.84 Canis Majoris
2018 Oct 13 07h 11m 29s -13° 41’ 53” 11.89 Canis Majoris
2018 Oct 14 07h 12m 43s -14° 39’ 20” 11.94 Canis Majoris
2018 Oct 15 07h 13m 54s -15° 35’ 16” 11.99 Canis Majoris
2018 Oct 16 07h 15m 02s -16° 29’ 40” 12.04 Canis Majoris
2018 Oct 17 07h 16m 06s -17° 22’ 39” 12.09 Canis Majoris
2018 Oct 18 07h 17m 08s -18° 14’ 12” 12.14 Canis Majoris
2018 Oct 19 07h 18m 06s -19° 04’ 22” 12.20 Canis Majoris
2018 Oct 20 07h 19m 00s -19° 53’ 11” 12.25 Canis Majoris
2018 Oct 21 07h 19m 50s -20° 40’ 41” 12.30 Canis Majoris
2018 Oct 22 07h 20m 38s -21° 26’ 57” 12.35 Canis Majoris

Distance of Comet 21P/Giacobini-Zinner from Earth

The following chart shows the distance of Comet 21P/Giacobini-Zinner from Earth as a function of time. Distance data is measured in Astronomical Units and sampled with a 2 days interval.

The reported distances might be inaccurate around the times of closest approach for objects passing extremely close to Earth. The value of the distance of 21P/Giacobini-Zinner is also available as a real time updated value in the Live Position and Data Tracker.

Distance of Comet 21P/Giacobini-Zinner from Earth between January 2013 and December 2075

Light Curve of Comet 21P/Giacobini-Zinner

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 2075

Comet 21P/Giacobini-Zinner Orbital Elements

The following table lists the orbital elements of Comet 21P/Giacobini-Zinner at epoch 01 July 2018 00:00 UTC (JD: 2458301.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.71045299
Orbit inclination i 31.99755662°
Perihelion distance q 1.01282072 AU
151,515,824 km
Aphelion distance Q 5.98307773 AU
895,055,691 km
Semi-major axis a 3.49794923 AU
523,285,757 km
Orbital period period 6.5400 years
2,389.5641 days
Date of perihelion transit Tp 2018-Sep-10 06:40:11
2,458,371.7779 JD
Next perihelion transit 2025-Mar-26 20:12
2,460,761.3420 JD
Argument of perihelion peri 172.86099203978°
Longitude of the ascending node node 195.39202846797°
Mean anomaly M 349.41227464986°
Mean motion n 0.15065509°/day
Closest approach to Earth* 2058-Sep-19
Distance of closest approach* 0.36548523 AU
54,675,813 km

* NOTE: values for the closest approach are computed for the time interval between 2013-Jan-01 and 2075-Dec-31, with a sampling interval of 1 day.