Gnomon is an archaeoastronomical horology timepiece and contemplative seasonal companion for iPhone, iPad, and Apple Watch. Rooted in ancient solar observation and the 72 micro-seasons of East Asian tradition, Gnomon translates celestial motion into an offline, quiet daily ritual.
At the heart of Gnomon is a physical 3D sundial, rendered entirely in real-time ray optics. Unlike simplistic 2D shadow renderers, Gnomon models the sun as an extended light source, reproducing a dense, sculptured umbra core that progressively diffuses into an organic penumbra envelope as shadows stretch across the white-jade lotus pedestal.
TIME MEASURED BY SUNLIGHT
• True Solar-Noon Geometry: Stand with the quiet voxel observer and track the shadow cast precisely at local astronomical solar noon across the equinoxes, solstices, and 24 solar terms (1970–2100).
• Local True Solar Noon Ceremony: At exact local apparent solar noon (12:00 AST), experience a pure procedural synthesis of the Song Dynasty Dasheng bronze chime (黄钟大晟特磬, 261.63 Hz) combined with gentle tactile mallet haptics.
• Dual-Shadow Comparison: Compare today's shadow with the same day last month, the solstice extremes, or an observation site in the opposite hemisphere.
• Dynamic Seasonal Atmosphere: An eight-node sky gradient breathing with solar longitude and local diurnal cycles, transitioning from morning dew to twilight amber.
72 MICRO-SEASONS & MINDFUL RITUALS
• Sourced Cultural Lore: Journey through the 72 micro-seasons (Pentads), from "First East Wind Melts the Ice" to "Rotting Grass Turns to Fireflies."
• Today's Invitation: Every solar term introduces an original invitation for mindful living—an invitation to notice where light falls, brew tea with the season's water, or leave space for what comes next.
• Procedural Soundscapes: Immerse yourself in synthesized elemental acoustic hums tailored to each season's nature without requiring audio file streaming or downloads.
• Lunisolar Almanac: Explore the synchronicity of the lunar phase, solar longitude, and celestial stems in an understated single-line footnote that unfolds only when invited.
CRAFT & RESTRAINT
• 100% Offline & Private: High-precision VSOP87D planetary calculation algorithms run locally on device. No accounts, no analytics, no network dependency, and no tracking.
• Quiet Typography: Designed with reverence for Songti serif typography, warm Xuan-paper tones, and restrained cinnabar seals. No notifications, no streaks, and no feed clutter.
• Standalone Apple Watch & Complications: Scrub through a year of light using the Digital Crown on your wrist with real-time true solar noon countdowns.
• Full Accessibility: Complete VoiceOver support, dynamic type adaptation, and respect for Reduce Motion.
Step outside, notice where the shadow falls, and make room for the light.
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