What telescope do I need to see Didymos?

At magnitude 14.3, Didymos is a challenging target that needs at least an 8-inch (200 mm) telescope and dark skies.

Didymos — Oggetto Near-Earth in Ophiuchus

65803 Didymos, 1996 GT

Magnitudine 14.3^m NearEarthObject Ophiuchus Visibile

Mappa stellare Sistema Solare 3D + Lista + Piano Star Hop

Proprietà

Magnitudine 14.3

Descrizione

Type: Near-Earth Object

Distance: 1.643 AU

Orbital Period: 768.9 days

Diameter: 1 km

Features: Equatorial ridge typical of fast rotators; rubble-pile structure

Binary asteroid system: a roughly 780 m S-type primary with a small ~150 m moonlet (Dimorphos). Target of NASA's DART mission, the first planetary-defence test, which impacted Dimorphos in September 2022 and shortened its orbital period by ~33 minutes. ESA's Hera mission visits in late 2026.

Posizione e identificatori

RA 16h 36m 26.3s

Dec -22° 40' 46.0"

Costellazione Ophiuchus

Catalogo Didymos

Proprietà fisiche

Diametro 1 km

Massa 5.28e11 kg

Albedo 0.15 (15% reflected)

Rotazione 2.3 hours

Superficie Equatorial ridge typical of fast rotators; rubble-pile structure

Dimensione angolare 0.0″ (current)

Proprietà orbitali

Semiasse maggiore 1.6426 AU (245.7 million km)

Eccentricità 0.3832

Inclinazione 3.41°

Periodo orbitale 2.11 years

Distanza 0.915 AU (7.6 light-min)

Elongazione 166.3° Near opposition

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.

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.

Consigli per l'osservazione

Visibilità Large telescope only at close approach

Dove cercare Near-Earth asteroid (Apollo group); inner-Earth crosser

Note Binary asteroid system: a roughly 780 m S-type primary with a small ~150 m moonlet (Dimorphos). Target of NASA's DART mission, the first planetary-defence test, which impacted Dimorphos in September 2022 and shortened its orbital period by ~33 minutes. ESA's Hera mission visits in late 2026.