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Comet Near-Earth

Siding Spring

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P/2006 HR30 (Siding Spring)

Where is it now

Distance from Sun
6.928 AU
True anomaly
216.96°
Distance from Earth
7.01 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.

Sun Earth — 0.998 AU from the Sun Earth Siding Spring — 6.928 AU from the Sun Siding Spring
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Siding Spring is 7.01 AU from Earth today (58.3 light-minutes).

In the sky

Right ascension
18h 45m 29s
Declination
-36° 05′ 34″
Constellation
Sagittarius
Distance from Earth
7.02 AU
Elongation from the Sun
80.7° — 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
7.818 AU
Eccentricity
0.8431
Inclination
31.88°
Orbital period
21.86 years
Perihelion
1.226 AU
Aphelion
14.409 AU
Longitude of ascending node
309.95°
Argument of periapsis
117.41°
Epoch · J2000
2454065.5
Orbit class · HTC
Halley-type comet
Earth MOID · 176.2 LD
0.4527 AU
Tisserand (Jupiter)
1.785

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
3,073
Data arc
21.02 years
First observed
6 July 2005
Last observed
14 July 2026
Residual RMS
0.43 ″
Solution · Otto Matic
7 August 2026

Physical properties

Rotation period
2.95 days

Visual & observation

Absolute magnitude (H)
13.9
Total magnitude M₁ · K₁ 4.5
13.9

Discovery & classification

Also known as 2006 HR30 · P/2026 M4

Near-Earth Object Named

Close approaches 1 on record

When (UTC) Body Distance Lunar distances Relative speed
2091-12-10 16:21:00 Juptr 0.5855 AU 227.9 LD 14.3 km/s

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

Sources