Accurate astronomical calculations powered by NASA JPL ephemeris data. No external API dependencies — all calculations are done locally using pure mathematics. Features: - Moon phases (new moon, first quarter, full moon, last quarter) with illumination percentage - Next/previous new moon and full moon dates - Sunrise and sunset times for any GPS location worldwide - Solar noon, day length calculation - Civil, nautical, and astronomical twilight times - Equinox and solstice dates for any year (1900-2100) - Zodiac signs based on exact astronomical position of the sun - Complete solar and lunar eclipse calendars Use cases: - Astronomy education and outreach apps - Photography planning (golden hour, blue hour, twilight) - Gardening and farming (planting by moon phases) - Astrology apps (accurate zodiac sign calculations) - Calendar and timekeeping applications - Outdoor event planning (sunrise/sunset times) - Religious and cultural observances