Home
Search Objects
Major Solar System Objects
Comets
Asteroids
Spacecrafts
Star Maps
Orbits
public  Miribel-les-Échelles, Francia Miribel-les-Échelles, Fran...  ⓘ
TimezoneEurope/Paris
Sunrise: 5:55 
Transit: 13:41 
Sunset: 21:27
Search  close
Comets » 

Comet 21P/Giacobini-Zinner

Above the horizon.  Rise: 7:03 | Tran: 13:16 | Set: 19:29
Alt: 26.50°   Az: 114.26°   Direction: East-South-East

Comet 21P/Giacobini-Zinner is in the constellation of Monoceros, at a distance of 388,028,587.0 kilometers from Earth. The current Right Ascension is 06h 29m 57s and the Declination is +03° 26’ 01” (apparent coordinates). The estimated magnitude of comet 21P/Giacobini-Zinner, computed using JPL Horizons's data, is 17.13).

Finder Charts

The sky charts below show, at different resolutions, the position of comet 21P/Giacobini-Zinner in the sky. Click on each chart to access the interactive star map tool.

Star map showing the position of comet 21P/Giacobini-Zinner in the constellation of Monoceros on F, d Y. Field of view: 50x30 degrees. View interactive star map.
Star map showing the position of comet 21P/Giacobini-Zinner in the constellation of Monoceros on F, d Y. Field of view: 15x9 degrees. View in interactive star map.

The following map uses photographic imagery from the Digitized Sky Survey (DSS) to realistically visualize the precise position of comet 21P/Giacobini-Zinner against the stars in the background. The horizontal size of the map measures 60 arcminutes. Click on the image to access a more detailed full-screen view.

21P/Giacobini-Zinner
RA: 06h 28m 37s
Dec: +03° 27’ 06”
Simplified high-resolution deep sky chart showing the current position of comet 21P/Giacobini-Zinner. Field of view: 60 x 40 arcminutes. Go to the dedicated page

Equatorial Coordinates

Apparent

06h 29m 57s
+03° 26’ 01”
20h 20m 42s
02h 50m 40s

J2000

06h 28m 37s
+03° 27’ 06”

Additional Information

Monoceros
n/a
n/a
n/a
n/a
17.13

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.

Rise and Set Times

The following table lists today's rise, transit and set times of comet 21P/Giacobini-Zinner from Miribel-les-Échelles, Francia (all times relative to the local timezone Europe/Paris):

Azimuth: 86.6°
Max altitude: 48.0°
Azimuth: 273.4°

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.

Distance from Earth

The distance of comet 21P/Giacobini-Zinner from Earth is currently 388,028,587.0 kilometers, equivalent to 2.5938108957 Astronomical Units. Light takes 21m 34.324s to travel from comet 21P/Giacobini-Zinner and arrive to us.

388,028,587.0
2.5938108957
21m 34.324s

The following graph shows the distance of comet 21P/Giacobini-Zinner from Earth as a function of time. In the chart the distance is measured in Astronomical Units and the data is sampled with an interval of 1 day.

Chart of the distance of comet 21P/Giacobini-Zinner from Earth in Astronomical Units (au)
Note: The values in this chart may not be entirely accurate around the time of closest approach for objects passing very close to Earth at high speed (e.g., Near-Earth Objects).

The value of the distance of 21P/Giacobini-Zinner from Earth is also available as a real time updated value in the live position tracker.

Closest Approach to Earth

In the period between January 1, 2000 and December 31, 2099, the closest approach of comet 21P/Giacobini-Zinner to Earth will happen on Sunday 30 October 2078 at a distance of 0.289030 Astronomical Units, or 43,238,333 kilometers:

Sunday 30 October 2078
43,238,333
0.289030

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

Light Curve

The following chart shows the light curve of comet 21P/Giacobini-Zinner, i.e., its apparent magnitude as a function of time. The curve is calculated using the latest ephemerides provided by JPL Horizons. The magnitude data is sampled with the interval of 2 days. Because of this sampling, inaccuracies may occur for objects that have large variations of brightness over a few days. For comets, large discrepancies can arise between the calculated brightness and the observations due to their highly dynamic, and not always precisely predictable, behavior.

Chart of the magnitude of comet 21P/Giacobini-Zinner as a function of time

Orbital Elements

The following table lists the orbital elements of comet 21P/Giacobini-Zinner at epoch November, 12 2017 00:00 UTC (JD: 2458070.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.71047048
Orbit inclination i 32.00259232°
Perihelion distance q 1.01344100 AU
151,608,616 km
Aphelion distance Q 5.98716470 AU
895,667,092 km
Semi-major axis a 3.50030285 AU
523,637,854 km
Orbital period period 6.5489 years
2,391.9762 days
Date of perihelion transit Tp September 10, 2018
2,458,371.7659 JD
Next perihelion transit March 29, 2025
2,460,763.7421 JD
Argument of perihelion peri 172.81248242749°
Longitude of the ascending node node 195.40448019669°
Mean anomaly M 314.65852733856°
Mean motion n 0.15050317°/day

Orbit Visualization

The following chart is a 3D animated visualization of the orbit of comet 21P/Giacobini-Zinner relative to the other major objects in the Solar System. You can access more advanced features using our 3D Solar System Viewer.

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. Apparent celestial coordinates are provided.

Date Right AscensionR.A. DeclinationDec. MagnitudeMag Constellation
Jun 27 2025 06h 10m 16s +04° 13’ 03” 16.92 Orion
Jun 28 2025 06h 13m 01s +04° 06’ 54” 16.95 Orion
Jun 29 2025 06h 15m 44s +04° 00’ 40” 16.98 Orion
Jun 30 2025 06h 18m 27s +03° 54’ 21” 17.01 Orion
Jul 01 2025 06h 21m 09s +03° 47’ 56” 17.03 Orion
Jul 02 2025 06h 23m 50s +03° 41’ 25” 17.06 Monoceros
Jul 03 2025 06h 26m 29s +03° 34’ 50” 17.09 Monoceros
Jul 04 2025 06h 29m 07s +03° 28’ 09” 17.12 Monoceros
Jul 05 2025 06h 31m 44s +03° 21’ 24” 17.14 Monoceros
Jul 06 2025 06h 34m 20s +03° 14’ 34” 17.17 Monoceros
Jul 07 2025 06h 36m 55s +03° 07’ 40” 17.20 Monoceros
Jul 08 2025 06h 39m 28s +03° 00’ 40” 17.22 Monoceros
Jul 09 2025 06h 42m 01s +02° 53’ 35” 17.25 Monoceros
Jul 10 2025 06h 44m 32s +02° 46’ 27” 17.27 Monoceros

Additional Resources on TheSkyLive