A view from Earth, across a hundred thousand years in either direction.
Optional: your overhead sky
Use location only if you want an overhead view.
Date and time set the overhead viewing direction. The year slider then moves the stars while holding that reference direction fixed.
About the model & data
Stellar positions, distances, proper motions and radial velocities are based on the supplied HYG catalog, with some updated catalog measurements. No star is preselected or treated specially. Positions are propagated from their J2000 epoch using constant 3D space velocities. The RA proper-motion component already includes cos(dec).
Location comes from the browser’s location service with your permission, or from manual entry. Latitude/longitude preferences are kept in your browser; these pages do not send your coordinates to a server. Automatic location availability depends on your browser and page origin; HTTPS is normally required for web hosting. If permission is declined or unavailable, enter the coordinates manually.
The overhead direction uses USNO mean sidereal time and latitude, precessed back into the catalog’s J2000 frame using the IAU 1976 model. The observing date/time controls support 1900–2100. The long-term year slider changes stellar positions while keeping this chosen viewing direction fixed; it does not simulate Earth’s daily rotation, long-term axial precession, daylight, atmosphere, or a horizon.
Only the 31 familiar names in your original pages are used for automatic labels. Rendered stellar light follows apparent-magnitude flux ratios, with compact cores and subtle halos for bright stars. The default limiting magnitude is 6.5, a dark-sky naked-eye reference. Monitor brightness and viewing conditions vary; the display is illustrative rather than a calibrated view. Selected-star emphasis is off by default.
Missing radial velocities are treated as zero. Stars without usable distances are shown as distant references. These are illustrative predictions: gravity, binary orbits, light-travel time and uncertainties are omitted. The Milky Way glow is an infinitely distant, static modern reference. Stars, labels, lines and the background use the same stereographic projection to reduce wide-field edge stretching. Stereographic views preserve local shapes, but angular scale still varies across the image. Mouse-wheel travel translates the observer through the catalog in a sphere of radius 20 light-years around Earth, without changing the 110° vertical field of view.
Constellation lines are connecting guides from your original file. Deep-sky catalog searches point to fixed sky coordinates; they do not add galaxy or nebula images. Input years use astronomical numbering: year 0 is 1 BC.
The stereo view uses parallel cameras with an exaggerated separation, rather than the tiny parallax of human eyes at real stellar distances. It is an illustration of depth as viewed near Earth.