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Comet 109P/Swift-Tuttle

Below the horizon.  Rise: 11:53 | Tran: 16:13 | Set: 20:32
Alt: -34.88°   Az: 75.19°   Direction: South-West

Comet 109P/Swift-Tuttle is in the constellation of Hydra, at a distance of 6,399,835,889.0 kilometers from Earth. The current Right Ascension is 09h 37m 06s and the Declination is -18° 28’ 10” (apparent coordinates). The estimated magnitude of comet 109P/Swift-Tuttle, computed using JPL Horizons's data, is 37.06).

Finder Charts

The sky charts below show, at different resolutions, the position of comet 109P/Swift-Tuttle in the sky. Click on each chart to access the interactive star map tool.

Star map showing the position of comet 109P/Swift-Tuttle in the constellation of Hydra on F, d Y. Field of view: 50x30 degrees. View interactive star map.
Star map showing the position of comet 109P/Swift-Tuttle in the constellation of Hydra 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 109P/Swift-Tuttle 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.

109P/Swift-Tuttle
RA: 09h 35m 55s
Dec: -18° 21’ 16”
Simplified high-resolution deep sky chart showing the current position of comet 109P/Swift-Tuttle. Field of view: 60 x 40 arcminutes. Go to the dedicated page

Equatorial Coordinates

Apparent

09h 37m 06s
-18° 28’ 10”
15h 46m 57s
01h 24m 04s

J2000

09h 35m 55s
-18° 21’ 16”

Additional Information

Hydra
n/a
n/a
n/a
n/a
37.06

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 109P/Swift-Tuttle from Greenwich, UK (all times relative to the local timezone Europe/London):

Azimuth: 108.5°
Max altitude: 20.1°
Azimuth: 251.5°

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 109P/Swift-Tuttle from Earth is currently 6,399,835,889.0 kilometers, equivalent to 42.7802605682 Astronomical Units. Light takes 5h 55m 47.555s to travel from comet 109P/Swift-Tuttle and arrive to us.

6,399,835,889.0
42.7802605682
5h 55m 47.555s

The following graph shows the distance of comet 109P/Swift-Tuttle 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 109P/Swift-Tuttle 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 109P/Swift-Tuttle 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, 2013 and December 30, 2100, the closest approach of comet 109P/Swift-Tuttle to Earth happened on Sunday 17 February 2013 at a distance of 32.765243 Astronomical Units, or 4,901,610,600 kilometers:

Sunday 17 February 2013
4,901,610,600
32.765243

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 109P/Swift-Tuttle, 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 109P/Swift-Tuttle as a function of time

Orbital Elements

The following table lists the orbital elements of comet 109P/Swift-Tuttle at epoch October, 09 1995 00:00 UTC (JD: 2450000.5). Source: JPL Small-Body Database

Element Symbol Value
Orbit eccentricity e 0.96322576
Orbit inclination i 113.45381700°
Perihelion distance q 0.95951616 AU
143,541,574 km
Aphelion distance Q 51.22462284 AU
7,663,094,520 km
Semi-major axis a 26.09206950 AU
3,903,318,047 km
Orbital period period 133.2818 years
48,681.1935 days
Date of perihelion transit Tp December 11, 1992
2,448,968.4998 JD
Next perihelion transit March 26, 2126
2,497,649.6932 JD
Argument of perihelion peri 152.98216763059°
Longitude of the ascending node node 139.38119208159°
Mean anomaly M 7.6316961671242°
Mean motion n 0.00739505°/day

Orbit Visualization

The following chart is a 3D animated visualization of the orbit of comet 109P/Swift-Tuttle 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 109P/Swift-Tuttle 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 20 2025 09h 36m 41s -18° 30’ 49” 37.05 Hydra
Jun 21 2025 09h 36m 44s -18° 30’ 25” 37.05 Hydra
Jun 22 2025 09h 36m 47s -18° 30’ 01” 37.05 Hydra
Jun 23 2025 09h 36m 51s -18° 29’ 38” 37.05 Hydra
Jun 24 2025 09h 36m 54s -18° 29’ 16” 37.05 Hydra
Jun 25 2025 09h 36m 58s -18° 28’ 55” 37.05 Hydra
Jun 26 2025 09h 37m 02s -18° 28’ 35” 37.05 Hydra
Jun 27 2025 09h 37m 05s -18° 28’ 16” 37.06 Hydra
Jun 28 2025 09h 37m 09s -18° 27’ 57” 37.06 Hydra
Jun 29 2025 09h 37m 13s -18° 27’ 39” 37.06 Hydra
Jun 30 2025 09h 37m 17s -18° 27’ 22” 37.06 Hydra
Jul 01 2025 09h 37m 21s -18° 27’ 05” 37.06 Hydra
Jul 02 2025 09h 37m 25s -18° 26’ 50” 37.06 Hydra
Jul 03 2025 09h 37m 29s -18° 26’ 35” 37.06 Hydra

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