Jupiter

Provenance-Backed Scientific Measurements

Every measurement below preserves its unit, uncertainty interval, observational method, reference epoch, quality status, and primary catalog source. See Uncertainty & Provenance for how competing measurements are handled.

J2000 Equatorial Sky Chart & Culmination Altitude

The chart below plots Jupiter (Gas Giant & Galilean Moons) at RA 06h 00m 00.00s, Dec +23° 00′ 00.0″ within Ecliptic (Zodiac), alongside peak meridian transit altitudes for 40°N and 30°S observers. Use the RA/Dec Coordinate Converter to compute exact culmination altitude for your latitude.

Astrophysical Context & Structure

Jupiter is the fifth planet from the Sun and the gravitational titan of our Solar System, packing 317.83 Earth masses (more than 2.5 times the combined mass of all other planets) into a rapidly rotating hydrogen-helium spheroid with an equatorial diameter of 142,984 kilometers (11.21 Earth radii). Because Jupiter spins on its axis in just 9 hours 55 minutes 30 seconds—the shortest day of any planet—centrifugal forces flatten its disk by 6.49%, making its polar diameter 9,276 kilometers shorter than its equatorial diameter.

In January 1610 Galileo Galilei turned his 20× spyglass on Jupiter and discovered its four major moons—Io, Europa, Ganymede, and Callisto—revolving in a miniature Copernican plane around the planet, providing the first direct observational proof that not all celestial bodies orbit Earth. NASA's Juno spacecraft, orbiting Jupiter since 2016, has used high-precision gravity harmonics to show that Jupiter does not have a small, sharp rocky core, but rather a 'dilute' or fuzzy core of heavy elements dissolved into metallic hydrogen across nearly half the planet's radius.

Jupiter's dynamic ammonia-hydrosulfide cloud deck is divided into bright upwelling 'zones' and dark descending 'belts,' anchored by the Great Red Spot—an anticyclonic vortex larger than Earth that has persisted in the South Equatorial Belt for at least 190 to 350 years.

Practical Visual Observing Guide

• Shining between magnitude −1.7 and −2.94, Jupiter outshines every star in the sky and is surpassed only by the Moon, Venus, and occasionally Mars at perihelic opposition.
• Even steadily held 7×50 or 10×50 binoculars resolve the four Galilean moons (magnitudes 4.6 to 5.7) shifting positions from night to night.
• In any 60–150 mm telescope at 120×–220×, you can observe the North and South Equatorial Belts, the polar flattening, the Great Red Spot rotating across the disk, and black pinhole shadow transits cast by Io, Europa, Ganymede, and Callisto onto the cloud tops.

Catalog Cross-Identifications & Aliases

Common Aliases: Jove · Sol V

Related Objects, Comparisons & Guides

Scientific Sources & Dataset Provenance

• NASA/JPL Solar System Dynamics & Planetary Fact Sheets (DE441 (2021/2026)): Park, R. S., et al. 2021, AJ, 161, 105 (The JPL Planetary and Lunar Ephemerides DE440 and DE441) — NASA Jet Propulsion Laboratory / GSFC