I built Zenith: a live local-first fixed viewport planetarium
2 hours ago
- #Earth rotation
- #real-time sky map
- #astronomy visualization
- The project Zenith provides a real-time zoomed-in view of stars, making the Earth's rotation visible by using a field of view equivalent to the sky turning in 30 seconds.
- It uses images from the Pan-STARRS telescope survey (2010-2014) for resolution and coverage, hosted at the Space Telescope Science Institute (STScI), with no server-side processing; all operations are client-side in JavaScript.
- The view shows a thin ribbon of the sky, unique to each latitude and repeating every sidereal day; people at the same latitude share the same view but with time offsets east or west.
- Astronomers counteract Earth's rotation with equatorial mounts to keep stars in view, while Zenith intentionally omits this to highlight the motion.
- Location data is requested to customize the sky view but is not transmitted externally; declining defaults to Stonehenge.
- A coordinate grid (0.5 arcminutes per side) overlays the view, using Right Ascension and Declination similar to Earth's latitude and longitude.
- Image processing includes white edge removal and noise filtering, but oversaturation from bright stars remains an unsolved issue, causing color distortions.
- Object names are sourced from the SIMBAD database, aligning accurately with stars in the images via tools like Leaflet.js for tiling and overlays.
- The project was inspired by the experience of observing stars drift through a telescope, emphasizing the perception of Earth's rotation.
- It's designed for potential installation as a ceiling projection, offering an immersive way to visualize celestial motion.