Jupiter

Construction

The globe is rendered in Three.js at the equatorial radius, built as a true oblate spheroid at the polar/equatorial ratio 66,854/71,492 = 0.9351256. Each texture row is placed at its own planetocentric latitude on the ellipsoid; compressing a sphere along the spin axis instead would place it at the parametric latitude and displace features by up to 1.9° (about 2,300 km). Markers are placed on the same ellipsoid. The base coat is the Cassini cloud-top mosaic of December 2000: the rendered surface is the top of the ammonia-ice cloud deck, bright zones of rising gas alternating with dark, descending belts. No topography exists, so no relief layer is provided. Textures are loaded from Maps/textures/jupiter_color_*.jpg.

Features and research feed

The named features in Data/worlds/jupiter/features.json are atmospheric rather than geological: the Great Red Spot and Oval BA anticyclones, the belts (NEB, SEB, …) and zones, the circumpolar cyclone arrays reported at both poles by Juno, an NEB 5-µm hot spot, and the entry site of the Galileo probe, the only spacecraft to have descended into a giant planet. Positions are tied to the System III frame of the Cassini map rather than treated as fixed coordinates, since the cloud features drift in longitude. The research panel queries body_server.py at /api/jupiter/latest (NASA ADS, with arXiv as fallback) and a per-feature endpoint for the selected feature; absent a server it falls back to the seed research.json and to ADS search links.

Live panel

The central-meridian readout gives the System I, II and III longitudes facing Earth at the current instant, from the Project Pluto linear-plus-correction formula; the four-term correction accounts for the synodic geometry, the light-time lag and the orbital eccentricity of Jupiter. Residuals against the JPL Horizons sub-observer longitude are within about 2° over 2015–2030, with the System III rate corrected to 870.4529147°/d as noted in the source. The Great Red Spot longitude and its next central-meridian transits follow from the System II meridian and a drift model anchored to JUPOS (79° at 2025-12-01, drift 16°/yr); CFG.grsRef is updated as JUPOS publishes new measurements. The Galilean-moon strip is computed from the JupiterMoons state vectors of Astronomy Engine, projected onto the sky plane to give each elongation and to flag transits, occultations and shadow transits in progress, subject to the small phase-angle ambiguity. The community image is the most recent amateur image of Jupiter, retrieved by body_server.py from the PVOL2 (UPV/EHU Bilbao) EPN-TAP archive and proxied same-origin. The missions list carries arrival countdowns for the spacecraft in transit, Europa Clipper (Jupiter orbit insertion April 2030) and JUICE (July 2031), alongside Juno, whose extended mission expired 30 September 2025. Each feed carries a status lamp and degrades to a static state when the server is unavailable.

Locator

The final panel is a top-down plan of the solar system. All eight planets are placed from Astronomy Engine (heliocentric ecliptic longitude and distance), with orbit radii √-scaled so that Mercury and Neptune both resolve on one dial. The dashed Earth–Jupiter line is the sightline: its length sets the light-time, and its Sun–Earth–Jupiter angle gives the elongation and the date of the next opposition. The three values are shown beside it. Europa Clipper and JUICE are drawn from their cruise trajectories as flown (JPL Horizons geometric states sampled monthly into Data/worlds/jupiter/cruise.json, gravity-assist loops included), with a marker interpolated to the current date. The panel refreshes on the same tick as the almanac.

Calibration

Longitudes are placed in the System III frame of the Cassini cylindrical map (map centred; left edge −180°). The Great Red Spot is the anchor, at 19.6°S planetocentric — equivalently 22.2°S in the planetographic convention the literature quotes. The PIA07782 map covers equal increments of planetocentric latitude, so that is the frame the markers are placed in. Not every entry in the feature file has been re-derived to it: Oval BA at −33 and the SSTB ovals at −40 are still the planetographic literature values, and are displaced by up to 3.8° at mid-latitudes until reconciled. Spot longitudes are not permanent: the Great Red Spot drifts in System II and the belts overturn on multi-year cycles. The values record the 2000 epoch and are not an ephemeris.

• Porco, C. C. et al. 2003 — Cassini Imaging of Jupiter's Atmosphere, Satellites, and Rings, Science 299, 1541–1547. doi:10.1126/science.1079462
• NASA/JPL/Space Science Institute — Cassini's Best Maps of Jupiter (Cylindrical Map), PIA07782; 36 narrow-angle-camera images in two colours, 11–12 Dec 2000
• Bolton, S. J. et al. 2017 — Jupiter's interior and deep atmosphere: The initial pole-to-pole passes with the Juno spacecraft, Science 356, 821–825. doi:10.1126/science.aal2108
• Adriani, A. et al. 2018 — Clusters of cyclones encircling Jupiter's poles, Nature 555, 216–219. doi:10.1038/nature25491
• Simon, A. A. et al. 2018 — Historical and Contemporary Trends in the Size, Drift, and Color of Jupiter's Great Red Spot, Astron. J. 155, 151. doi:10.3847/1538-3881/aaae01
• Archinal, B. A. et al. 2018 — Report of the IAU Working Group on Cartographic Coordinates and Rotational Elements: 2015, Celest. Mech. Dyn. Astron. 130, 22. doi:10.1007/s10569-017-9805-5 — System III rotation model, W = 284.95° + 870.5360°/d
• Hueso, R. et al. 2018 — The Planetary Virtual Observatory and Laboratory (PVOL) and its integration into the Virtual European Solar and Planetary Access (VESPA), Planet. Space Sci. 150, 22–35. doi:10.1016/j.pss.2017.03.014 — community imagery
• Gray, J. (Project Pluto) — Formula for Jupiter's central meridians and Great Red Spot transits; Great Red Spot longitudes via JUPOS
• Cross, D. 2017– — Astronomy Engine (MIT) — Galilean-moon state vectors & planet positions
• Giorgini, J. D. et al. — JPL Horizons — Europa Clipper (-159) & JUICE (-28) cruise trajectories