StarWindow combines a stargazing index, dark-sky map, live sky map, Milky Way core timing, sunset glow, cloud-sea hints, sunrise, tides, moon phases and astronomy events to help decide whether tonight is worth heading out.
Stop cross-checking page by page. Start with tonight's stargazing index, find a dark-sky spot, confirm the galactic-core direction, or switch to sunset and cloud-sea planning.
Is tonight good for stars? · Where is the sky darker? · Japan Milky Way travel · Which way is the Milky Way? · Sunset glow or cloud sea? · Alert me when it is good
Retrograde motion, opposition, tides, precession — each lesson comes with a diagram you drive yourself, and its numbers are computed from orbital elements on the spot rather than typed in.
Why planets appear to move backwards · Opposition and conjunction · Greatest elongation · How auroras form · Solar and Lunar Eclipses · How a meteor lights up · The ecliptic plane · Tides: reading the Moon and Sun from the shore · Tidal locking: why does the Moon keep the same face toward us? · Solar System Orrery · Comets: from icy nucleus to extreme orbit · Ptolemaic and heliocentric · Perihelion precession
Taipei · New Taipei · Taichung · Tainan · Kaohsiung · Hualien · Taitung · Kenting · Tokyo · Okinawa (Naha) · Honolulu
New Taipei·Fulong Beach · Taichung·Gaomei Wetlands · Taitung·Jinzun Surfing · Hualien·Qixingtan · Kenting·Nanwan Beach · Pingtung·Xiaoliuqiu · New Taipei·Longdong Bay · New Taipei·Zhongjiao Bay