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Comet

Kowal

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99P/Kowal 1

Where is it now

Distance from Sun
6.819 AU
True anomaly
130.07°
Distance from Earth
6.331 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 Kowal — 6.819 AU from the Sun Kowal
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Kowal is 6.331 AU from Earth today (52.7 light-minutes).

In the sky

Right ascension
21h 54m 15s
Declination
-16° 50′ 07″
Constellation
Capricornus
Distance from Earth
6.35 AU
Elongation from the Sun
114.62° — well clear of the Sun

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
6.135 AU
Eccentricity
0.2298
Inclination
4.34°
Orbital period
15.19 years
Perihelion
4.725 AU
Aphelion
7.544 AU
Longitude of ascending node
28.18°
Argument of periapsis
174.2°
Epoch · J2000
2457072.5
Orbit class · JFc
Jupiter-family comet (P < 20 y)
Earth MOID · 1,448.3 LD
3.7216 AU
Tisserand (Jupiter)
2.956

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
1,734
Data arc
48.41 years
First observed
24 April 1977
Last observed
22 September 2025
Residual RMS
0.61 ″
Solution · Shantanu Naidu
8 September 2026

Physical properties

Mean radius
5.10 km

Visual & observation

Absolute magnitude (H)
6.8
Total magnitude M₁ · K₁ 12
6.8

Discovery & classification

Discovered by
Kowal, Charles T.
Discovery date
24 April 1977
Discovery site
Palomar Mountain Observatory, California

Also known as 99P · 1977 III · 1977f · 1991i · 1992 VI · 99P/1977 H2 · 99P/1991 D2

Named

Close approaches 15 on record

When (UTC) Body Distance Lunar distances Relative speed
2051-01-30 00:26:00 Jupiter 0.3376 AU 131.4 LD 3.4 km/s
2051-01-30 00:26:00 Juptr 0.3376 AU 131.4 LD 3.4 km/s
2054-09-29 20:46:00 Juptr 1.6343 AU 636.0 LD 1.2 km/s
2101-08-20 14:51:00 Juptr 1.4828 AU 577.1 LD 6.4 km/s
2135-01-31 10:42:00 Jupiter 0.4017 AU 156.3 LD 3.3 km/s
2135-01-31 10:42:00 Juptr 0.4017 AU 156.3 LD 3.3 km/s
2169-04-07 07:15:00 Jupiter 0.3737 AU 145.4 LD 3.3 km/s
2169-04-07 07:15:00 Juptr 0.3737 AU 145.4 LD 3.3 km/s

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

Sources