Skip to content
Public Universe
Comet

Spacewatch-Hill

Add to an observing list or journal →

393P/Spacewatch-Hill

Where is it now

Distance from Sun
5.1 AU
True anomaly
229.72°
Distance from Earth
6.015 AU
As of
22 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 — 0.995 AU from the Sun Earth Spacewatch-Hill — 5.1 AU from the Sun Spacewatch-Hill
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Spacewatch-Hill is 6.015 AU from Earth today (50.0 light-minutes).

In the sky

Right ascension
15h 05m 53s
Declination
-22° 03′ 19″
Constellation
Libra
Distance from Earth
6.02 AU
Elongation from the Sun
20.57° — near the Sun — look low at dusk or dawn

Favours the southern hemisphere; low or below the horizon from far north.

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
4.774 AU
Eccentricity
0.1196
Inclination
16.81°
Orbital period
10.43 years
Perihelion
4.202 AU
Aphelion
5.345 AU
Longitude of ascending node
36.41°
Argument of periapsis
328.59°
Epoch · J2000
2455912.5
Orbit class · JFc
Jupiter-family comet (P < 20 y)
Earth MOID · 1,251.2 LD
3.215 AU
Tisserand (Jupiter)
2.911

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
140
Data arc
11.23 years
First observed
17 September 2009
Last observed
11 December 2020
Residual RMS
0.65 ″
Solution · Otto Matic
20 February 2024

Visual & observation

Absolute magnitude (H)
7.6
Total magnitude M₁ · K₁ 16.8
7.6

Discovery & classification

Also known as 393P · 393P/2009 SK280 · 393P/2019 S5

Named

Close approaches 10 on record

When (UTC) Body Distance Lunar distances Relative speed
2088-10-26 18:27:00 Juptr 1.1302 AU 439.9 LD 4.3 km/s
2094-11-08 19:42:00 Juptr 0.4956 AU 192.9 LD 4.6 km/s
2094-11-08 19:42:00 Jupiter 0.4956 AU 192.9 LD 4.6 km/s
2152-08-28 13:53:00 Juptr 1.8226 AU 709.3 LD 6.1 km/s
2158-12-21 03:06:00 Juptr 1.32 AU 513.7 LD 3.5 km/s

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

Sources