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Amphitrite — Asteroid in Ophiuchus

29 Amphitrite

Asteroid Ophiuchus Visible
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Properties

Magnitude 9.0
Type: Asteroid
Distance: 2.554 AU
Orbital Period: 1490.9 days
Diameter: 190 km
Greek goddess of the sea, wife of Poseidon; S-type; one of the brightest minor planets at opposition (typical mag 9.0).

Position & Identifiers

RA 16h 42m 01.4s
Dec -30° 29' 06.2"
Constellation Ophiuchus
Catalog Amphitrite

Physical Properties

Diameter 190 km
Mass 8.9e18 kg
Albedo 0.22 (22% reflected)
Rotation 5.4 hours
Angular Size 0.1″ (current)

Orbital Properties

Semi-major Axis 2.5541 AU (382.1 million km)
Eccentricity 0.0734
Inclination 6.08°
Orbital Period 4.08 years
Distance 1.847 AU (15.4 light-min)
Elongation 146.0° Good

Brightness Forecast (next 12 months)

Apparent magnitude as Earth–asteroid distance changes through the year. The peak marks the brightest moment in the window — usually around opposition, when the asteroid is closest and fully illuminated.

10.0MayJunJulAugSepOctNovDecJanFebMarAprpeak 9.2 · 30 MaynowMagnitude↑ brighter

Computed from JPL orbital elements via m = H + 5·log10(r·Δ). Phase-function correction is omitted, so curves trace distance variation only — accurate within a few tenths for main-belt asteroids; coarse for fast-moving NEOs near Earth.

Observing Tips

Best Months April , May , June
Visibility Telescope
Where to Look In asteroid belt
Notes Greek goddess of the sea, wife of Poseidon; S-type; one of the brightest minor planets at opposition (typical mag 9.0).

Discovery

Discovered by Albert Marth
Date 1854-03-01

Current Ephemeris

1.847
AU from Earth
276.4M
km
0.1
Angular Size
146°
Elongation

How easy to spot?

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Telescope Bortle 3 Bortle 4 Bortle 5
80mm refr. Medium+ Medium+ Medium
150mm Newt. Easy Easy Easy
C8 203mm Easy Easy Easy
Easy Medium Hard Very hard Impossible

Bortle 3 = rural · 4 = outer suburbs · 5 = suburbs

Easy on Seestar S50

Visibility

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Community Photos (1)

Rendered preview of Amphitrite from the Nightbase orrery, lit from the current Sun direction with the terminator visible.

Rendered preview of Amphitrite from the Nightbase orrery, lit from the current Sun direction with the terminator visible.

Credit: Nightbase orrery render.

Skybred Apr 27, 2026

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