Comet 21P/Giacobini-Zinner
Comet 21P/Giacobini-Zinner is in the constellation of
Taurus,
at a distance of
Finder Charts
View interactive star map
High precision deep sky finder chart, 60 arcmin wide, showing where Comet 21P/Giacobini-Zinner is right now. Click on the image to see a more detailed fullscreen tracker view.
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.
Celestial Coordinates
Apparent
J2000
Additional Information
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
Today's rise, transit and set times of Comet 21P/Giacobini-Zinner from Greenwich, UK (all times relative to the local timezone Europe/London):
- 21P/Giacobini-Zinner is below the horizon from Greenwich, UK.
- Given its current magnitude, 21P/Giacobini-Zinner is visible only through long exposure photography.
- Go to interactive sky chart
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Distance from Earth
The distance of Comet 21P/Giacobini-Zinner from Earth is currently
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.
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
Between 1 January 2000 and 31 December 2099, the closest approach of Comet 21P/Giacobini-Zinner to Earth happens on Sun Oct 30 2078 at a distance of 0.289030 Astronomical Units, or 43,238,333 kilometers:
NOTE: values for the closest approach are computed with a sampling interval of 1 day.
Light Curve
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.
Orbital Elements
The following table lists the orbital elements of Comet 21P/Giacobini-Zinner at epoch 12 November 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 | 2018-Sep-10 06:22:53 2,458,371.7659 JD |
| Next perihelion transit | 2025-Mar-29 05:48 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 |
View Comet 21P/Giacobini-Zinner in the 3D Solar System Simulator
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 |
|---|---|---|---|---|
| 2025 May 14 | 03h 48m 08s | +06° 54’ 08” | 15.64 | Taurus |
| 2025 May 15 | 03h 51m 49s | +06° 53’ 15” | 15.66 | Taurus |
| 2025 May 16 | 03h 55m 30s | +06° 52’ 12” | 15.69 | Taurus |
| 2025 May 17 | 03h 59m 09s | +06° 51’ 00” | 15.72 | Taurus |
| 2025 May 18 | 04h 02m 47s | +06° 49’ 41” | 15.75 | Taurus |
| 2025 May 19 | 04h 06m 23s | +06° 48’ 13” | 15.78 | Taurus |
| 2025 May 20 | 04h 09m 58s | +06° 46’ 36” | 15.81 | Taurus |
| 2025 May 21 | 04h 13m 32s | +06° 44’ 52” | 15.84 | Taurus |
| 2025 May 22 | 04h 17m 05s | +06° 42’ 59” | 15.87 | Taurus |
| 2025 May 23 | 04h 20m 37s | +06° 40’ 58” | 15.90 | Taurus |
| 2025 May 24 | 04h 24m 07s | +06° 38’ 47” | 15.93 | Taurus |
| 2025 May 25 | 04h 27m 35s | +06° 36’ 30” | 15.96 | Taurus |
| 2025 May 26 | 04h 31m 03s | +06° 34’ 05” | 15.99 | Taurus |
| 2025 May 27 | 04h 34m 29s | +06° 31’ 32” | 16.02 | Taurus |
Additional Resources on TheSkyLive
- Comet 21P/Giacobini-Zinner: Complete reference information on TheSkyLive.com.
- Where is Comet 21P/Giacobini-Zinner?: Key information on locating Comet 21P/Giacobini-Zinner in the sky.
- Distance from Earth: Find out how far Comet 21P/Giacobini-Zinner is from Earth right now.
- How Bright is Comet 21P/Giacobini-Zinner?: Current visual brightness (magnitude) and apparent size.
- Rise and Set Times: Comet 21P/Giacobini-Zinner's rise and set times from your location.
- Interactive Sky Map: planetarium-style interactive visualization of Comet 21P/Giacobini-Zinner's position in the sky.
- Live Position Tracker: high precision position tracker with deep space imagery.
- Ephemeris: 15 days Comet 21P/Giacobini-Zinner's computed ephemeris.
- Orbital elements: information about Comet 21P/Giacobini-Zinner orbital parameters.
- Orbit Visualization. 3d interactive visualization showing the orbit of Comet 21P/Giacobini-Zinner with respect to the major Solar System objects.