A developer has built Zenith, a live local-first planetarium that shows a real-time view of the stars above your current location. The project uses an extremely narrow viewport - roughly the size of a grain of rice held at arm's length - creating approximately 180x magnification. This slim field of view makes Earth's rotation visibly apparent as stars drift across the screen in just seconds.

The key innovation lies in how the developer defined the viewport: specifically calibrated to show how much the sky turns in 30 seconds. At this zoom level, all apparent star motion stems from Earth's rotation - no time-lapse or sped-up footage involved. Location data stays entirely on the user's device and never transmits to any server. Users who decline location access see a default view overhead Stonehenge instead.

Zenith pulls images from the Pan-STARRS telescope survey in Hawaii (2010-2014), served directly from the Space Telescope Science Institute's MAST archive. The client-side JavaScript application uses Leaflet.js for image tiling and queries the SIMBAD database for object identification. Resolution hits 0.26 arcseconds per pixel. One unsolved problem: the survey wasn't designed for aesthetic star images, so medium-bright stars often oversaturate the sensor, creating greenish artifacts the developer continues debugging.