Chart an invented star system -- a real spectral class, orbits, and named planets with rings and moons, reproducible from its seed.
The Solar System's planets carry Roman god names assigned millennia ago, but the thousands of worlds found since 1992 follow a drier scheme: a planet takes its star's catalog name plus a lowercase letter in order of discovery, starting at b -- Kepler-186f is the fifth planet found around star Kepler-186. The International Astronomical Union, arbiter of all official names, occasionally holds public campaigns that give exoplanets proper names like Dimidium or Poltergeist. Moons, by contrast, draw on wider mythology, from Shakespearean spirits at Uranus to Inuit and Norse figures at Saturn. This generator skips the catalogs and names its invented worlds the way fiction does -- pronounceable, evocative, and numbered only when a dynasty of planets shares a name.
Every press charts a star system nobody has cataloged: a star drawn from six real spectral classes -- red dwarf to blue giant, sized and colored to match -- with four to seven planets on their orbits, each with a seeded size, tint, and name, some ringed, some mooned. The seed on the card recreates any system exactly, and the Constellation Maker next door invents the skies to see it from.
Every result here is drawn using crypto.getRandomValues() -- the Web Crypto API's cryptographically secure randomness -- instead of Math.random(), so it's genuinely unpredictable, not just statistically random. Learn more.
Science-fiction writers and game masters get a setting in one press -- the star's class alone implies the story, from a dim red dwarf's huddled planets to a blue giant's doomed ones. Worldbuilders pair it with the Constellation Maker and Flag Designer to kit out a whole civilization; teachers use the spectral classes as a hook into real stellar astronomy.
Each press draws a 32-bit seed from the site's cryptographically secure randomness and builds outward: a star class picked from the real O-to-M spectrum's showable middle (its color and size follow the class), orbits spaced from the star to the card's edge with seeded jitter, and planets placed at random points along them -- size, color, rings on the larger ones, the occasional moon, and a syllable-built name each, with Roman numerals for planetary dynasties. Chart and caption come from the same seed, so they always agree.
Yes -- M through B are real spectral classes with roughly true-to-life colors, from cool red dwarfs to hot blue giants. The planets and their names are pure invention.
Yes -- star, orbits, planets, and names are all determined by the seed stamped on the card.
Larger seeded planets have a chance of rings, and any planet can draw a moon -- roughly a third do. It's flavor, not physics, but it follows the real pattern of giants being the ring-bearers.
Freely -- the SVG button in the card's corner copies the chart as a vector file with every orbit and label editable.
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