A LITTLE CLOSER TO THE COSMOS
Follow the Milky Way. Find a distant galaxy. Zoom in until a point of light becomes a world.
ABOVE THE HORIZON
Calculated for your chosen place and time. Visibility also depends on daylight, weather and light pollution.
SKY EXPLORER
GPU rendering for the Milky Way, registered galaxy and nebula photos, and resolved Moon and planets makes panning, zooming and time playback smoother at full texture detail. Positions, phases, surface orientation and photo registration retain the existing astronomical calculations. Compatibility rendering takes over automatically when GPU rendering is unavailable or interrupted.
Improved responsiveness: batched redraws, reduced texture sampling while panning/zooming or playing time, automatic full-detail refinement when motion stops, skipped invisible imagery work, on-demand deep-sky photos, and targeted memory-bounded caches. Astronomical positions, phases, orientation and image registration use the same calculations. Shared views retain the exact displayed sky time.
Added the coordinate-mapped Milky Way; searchable photographic galaxies and nebulae; deep zoom; detailed Moon and planetary maps; date/location-aware phases, IAU surface orientation, topocentric lunar libration and Saturn ring tilt; quick targets, follow-selection and extended share links. The sky workspace now has a darker observing theme.
First release: interactive sky, 8,920 catalog stars, Sun, Moon and seven planet positions, location/date/time controls, constellation guides, object search, horizon/grid/daylight layers, red-light mode, playback and share links.
A LITTLE CONTEXT
An original PopFun planetarium inspired by Stellarium Web. Drag to turn; scroll or use +/− to zoom. On the focused map use arrow keys, +/− and Home. Search works independently of horizon and daylight; Center reveals an object's direction even when below the horizon. All dates and clocks are UTC.
Positions: locally bundled Astronomy Engine 2.1.19 by Don Cross (MIT license) computes topocentric Sun, Moon, Mercury, Venus, Mars, Jupiter, Saturn, Uranus and Neptune coordinates, normal atmospheric refraction, lunar illumination, and precession/nutation for stellar J2000-to-horizon rotation. Supported app dates: 1900–2100. The model is separate from Orbit Explorer's JPL service.
Stars: HYG v4.1, David Nash / Astronexus, derived from Hipparcos, Yale Bright Star and Gliese catalogs. This modified catalog selects magnitude ≤6.5 and selected columns, under CC BY-SA 4.0 (notice). Positions include linear proper motion from J2000; annual parallax, aberration and binary motion are omitted. Magnitudes are catalog values; colors and marker diameters are illustrative. Faint stars are progressively hidden in daylight and in wide views on smaller screens.
Constellations: twelve original simplified stick guides and the Big Dipper asterism join HYG Hipparcos stars; these are selected familiar patterns, not official IAU boundaries or a complete constellation atlas. Search a guide name to find its anchor star.
Milky Way: NASA Deep Star Maps 2020, NASA/Goddard Space Flight Center Scientific Visualization Studio; Gaia DR2: ESA/Gaia/DPAC. The bright-star-free background is ICRF/J2000 plate carrée, RA 0h in the center with RA increasing left. It is reprojected through the same date/location/precession/nutation/refraction model as the catalog. We converted NASA’s EXR to JPEG and increase display brightness. It is archival imagery, not a live camera or naked-eye brightness prediction.
Galaxies and nebulae: Andromeda (M31), Orion (M42), Whirlpool (M51), and Ring (M57) have J2000 coordinates transformed with your date and observer. Hubble photo footprints use the published Orion, Whirlpool and Ring image centers, fields and north orientations. Andromeda’s WISE image is registered using the galaxy nuclei of M31/M32/M110. Registration is an educational visualization, not a plate-solving or astrometric-measurement service. Original photo credits and source links appear in the object panel. Infrared and emission-line colors are enhanced representations, not what the eye sees.
Moon and planets: Solar System Scope equirectangular maps, CC BY 4.0, based on NASA imagery (some mapping gaps filled by the publisher; colors enhanced). Surface maps are static reference mosaics, not current cloud/weather imagery. Bodies use physical angular sizes once resolved; small targets remain point markers. Zoom as far as 1.8 arcseconds field. The rendered phase uses the Sun/body/observer geometry, including observer parallax and iterated light time. Dated IAU2015 axes and prime meridians orient the surfaces; local horizon coordinates set the viewing roll. The Moon’s changing view includes modeled libration. Saturn’s oblate globe and equatorial rings use its dated axis, with front/back occlusion. Lunar terrain shadows, eclipses, ring shadows, differential atmospheric flattening and high-precision lunar physical-libration kernels are not modeled. Gas-giant maps follow reference rotation, not measured cloud motion. Uranus/Neptune detail is limited by the source maps.
Responsiveness: Checking renderer…. GPU rendering projects imagery and shades resolved bodies at full texture detail while you move or play time. Compatibility rendering uses fewer pixels during motion and restores full detail when motion stops. Both use the same celestial positions, phases, orientation and photographic alignment.
Display: stereographic sky projection and orthographic close-up globes. Photos are enhanced; daylight fades the background. Zoom to detail pauses playback, follows the object, hides daylight and hides the horizon if necessary; the below-horizon status remains explicit. Flat sea-level horizon; no weather/light pollution, terrain, satellites or telescope control. Suitable for learning and exploration, not navigation or precision observation.
Your browser handles calculations locally. No location service is contacted unless you explicitly use the browser's geolocation button. Shared links include coordinates, UTC time, camera, layers and selected object; anyone with the link can read them.