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Asteroid

Sirona

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116 Sirona (A871 RA)

Where is it now

Distance from Sun
2.809 AU
True anomaly
103.82°
Distance from Earth
3.508 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 Sirona — 2.809 AU from the Sun Sirona
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Sirona is 3.508 AU from Earth today (29.2 light-minutes).

In the sky

Right ascension
16h 27m 18s
Declination
-22° 37′ 04″
Constellation
Ophiuchus
Distance from Earth
3.51 AU
Elongation from the Sun
38.95° — 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
2.769 AU
Eccentricity
0.1381
Inclination
3.56°
Orbital period
4.61 years
Perihelion
2.386 AU
Aphelion
3.151 AU
Longitude of ascending node
63.68°
Argument of periapsis
94.02°
Epoch · J2000
2461200.5
Orbit class · MBA
Main-belt asteroid
Earth MOID · 544.5 LD
1.3992 AU
Tisserand (Jupiter)
3.321

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
5,075
Data arc
153.3 years
First observed
23 December 1872
Last observed
10 April 2026
Residual RMS
0.41 ″
Solution · Otto Matic
5 June 2026

Physical properties

Mean radius
36 km
Rotation period
12.03 hours

Visual & observation

Geometric albedo
0.256
Absolute magnitude (H)
7.77
Colour index (B–V)
0.87
Spectral type (SMASS)
Sk
Spectral type (Tholen)
S
Colour index (U–B)
0.43

Discovery & classification

Discovered by
Peters, C. H. F.
Discovery date
8 September 1871
Discovery site
Clinton

Also known as 116 · A871 RA · 1954 UC3 · 1998 EK13 · 1998 ES21

Main-Belt Asteroid Named

Close approaches 7 on record

When (UTC) Body Distance Lunar distances Relative speed
2047-01-28 01:16:00 Juptr 1.9473 AU 757.8 LD 2.7 km/s
2069-07-07 21:11:00 Juptr 1.8414 AU 716.6 LD 2 km/s
2129-11-29 02:24:00 Juptr 1.8945 AU 737.3 LD 2.4 km/s
2152-05-09 05:18:00 Juptr 1.8666 AU 726.4 LD 2 km/s

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

Sources