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Asteroid

Phaedra

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174 Phaedra (A877 RA)

Phaedra is an asteroid in the Main-belt asteroid orbit class. Its orbit takes it from 2.44 AU to 3.27 AU from the Sun; one orbit takes 4.83 years; it is about 65 km across. Discovered 2 September 1877 by Watson, J. C.. Orbit from the JPL solution of 5 June 2026.

Where is it now

Distance from Sun
2.452 AU
True anomaly
13.74°
Distance from Earth
3.062 AU
As of
25 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 — 0.994 AU from the Sun Earth Phaedra — 2.452 AU from the Sun Phaedra
Seen from above the ecliptic, north up, to scale. Grid: Earth's orbit in blue. Phaedra is 3.062 AU from Earth today (25.5 light-minutes).

In the sky

Right ascension
16h 57m 15s
Declination
-30° 35′ 42″
Constellation
Scorpius
Distance from Earth
3.07 AU
Elongation from the Sun
43.91° — 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
2.859 AU
Eccentricity
0.1455
Inclination
12.1°
Orbital period
4.83 years
Perihelion
2.443 AU
Aphelion
3.275 AU
Longitude of ascending node
327.26°
Argument of periapsis
291°
Epoch · J2000
2461200.5
Orbit class · MBA
Main-belt asteroid
Earth MOID · 567.7 LD
1.4587 AU
Tisserand (Jupiter)
3.254

Orbit quality

Orbit very well determined (uncertainty code 0).

Observations used
9,734
Data arc
148.6 years
First observed
3 September 1877
Last observed
30 March 2026
Residual RMS
0.28 ″
Solution · Otto Matic
5 June 2026

Physical properties

Mean radius
32 km
Rotation period
5.74 hours

Visual & observation

Geometric albedo
0.169
Absolute magnitude (H)
8.39
Colour index (B–V)
0.86
Spectral type (SMASS)
S
Spectral type (Tholen)
S
Colour index (U–B)
0.48

Discovery & classification

Discovered by
Watson, J. C.
Discovery date
2 September 1877
Discovery site
Ann Arbor

Also known as 174 · A877 RA

Main-Belt Asteroid Named

Close approaches 5 on record

When (UTC) Body Distance Lunar distances Relative speed
2048-02-08 09:16:00 Juptr 1.9897 AU 774.4 LD 1.9 km/s
2072-10-14 16:23:00 Juptr 1.9995 AU 778.1 LD 2.9 km/s
2178-11-20 08:24:00 Juptr 1.9839 AU 772.1 LD 2.1 km/s

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

Sources