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125P/Spacewatch

Where is it now

Distance from Sun
4.715 AU
True anomaly
175.83°
Distance from Earth
3.986 AU
As of
11 October 2026

Two-body Kepler propagation — accurate to ~0.1% for major planets over decades, less so for highly-perturbed bodies. Use JPL Horizons for high precision.

Orbit of Mercury Orbit of Venus Orbit of Mars Sun Earth — 0.998 AU from the Sun Earth Spacewatch — 4.715 AU from the Sun Spacewatch
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Spacewatch is 3.986 AU from Earth today (33.1 light-minutes).

In the sky

Right ascension
04h 20m 42s
Declination
+09° 32′ 08″
Constellation
Taurus
Distance from Earth
3.98 AU
Elongation from the Sun
132.95° — well clear of the Sun

Visible from both hemispheres.

From your location

See how high it is right now, whether it is up after civil twilight, and when it rises and sets where you are.

How do I find my coordinates?

Google Maps on a computer

  1. Right-click the spot where you'll be observing.
  2. The first line of the menu is the coordinates, e.g. 51.50722, -0.12758 — click it and they're copied.
  3. Paste them above.

Google Maps on a phone

  1. Press and hold the spot to drop a pin.
  2. The coordinates appear in the search bar (or on the pin's card) — tap to copy, then paste above.

A full Google Maps link works too, but the short maps.app.goo.gl share links don't carry coordinates — copy the numbers instead. We round to about a kilometre; that's all the sky calculation needs.

Know your what3words address? Paste it, e.g. ///filled.count.soap. This is optional — the three words are sent to what3words to convert them, and we don't store the address or the result.

Your location stays in your browser and is sent only for this calculation. Using a what3words address is optional; if you do, the three words go to what3words to be converted and we don't record them. Set a location first, then you can save an email alert for this object. See our privacy policy.

Two-body approximation, good to about a degree for the planets — enough to find the constellation and know whether it is up.

Orbital elements

Semi-major axis
3.126 AU
Eccentricity
0.5127
Inclination
9.99°
Orbital period
5.53 years
Perihelion
1.523 AU
Aphelion
4.728 AU
Longitude of ascending node
153.2°
Argument of periapsis
87.15°
Epoch · J2000
2457245.5
Orbit class · JFc
Jupiter-family comet (P < 20 y)
Earth MOID · 215.8 LD
0.5545 AU
Tisserand (Jupiter)
2.975

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
1,297
Data arc
33.12 years
First observed
8 September 1991
Last observed
21 October 2024
Residual RMS
0.66 ″
Solution · Shantanu Naidu
29 October 2024

Physical properties

Mean radius
0.80 km

Visual & observation

Absolute magnitude (H)
12.9
Total magnitude M₁ · K₁ 16
12.9

Discovery & classification

Discovered by
Gehrels, T.
Discovery date
8 September 1991
Discovery site
Kitt Peak

Also known as 125P · 125P/1991 R2 · 125P/1996 F1 · 1990 XXIX · 1991x

Named

Close approaches 12 on record

When (UTC) Body Distance Lunar distances Relative speed
2059-07-27 18:22:00 Juptr 0.9252 AU 360.1 LD 5.6 km/s
2071-09-05 08:12:00 Juptr 0.7615 AU 296.3 LD 4 km/s
2083-10-16 13:39:00 Juptr 0.7434 AU 289.3 LD 3.8 km/s
2095-06-14 06:36:00 Juptr 0.8461 AU 329.3 LD 4.2 km/s
2107-04-12 05:59:00 Juptr 1.9324 AU 752.0 LD 8.4 km/s
2179-02-04 15:06:00 Juptr 1.3085 AU 509.2 LD 7.6 km/s
2191-01-14 15:00:00 Juptr 0.5565 AU 216.6 LD 4.8 km/s

Next ten from today. 1 lunar distance = 384,400 km. Source: JPL close-approach data.

Sources