StarPlan

StarPlan is a professional offline tool for astronomical observation, designed for calculating celestial positions and simulating true telescope fields of view, rather than being an entertainment stargazing app. Amateur astronomers often face two common frustrations during fieldwork: no mobile network at remote mountain, plateau, or desert sites, making it impossible to quickly get a target's azimuth and altitude; and the vast size differences of deep-sky objects in a telescope's field, making it hard to predict if a specific telescope and eyepiece combination will frame the target properly. Starfinder solves both problems in a completely offline environment. It features a built-in database of bright stars, Messier, and selected NGC objects. Using local algorithms, it calculates celestial horizon coordinates and, based on your telescope and eyepiece parameters, draws a true field circle overlaid on a reference star chart near the target, helping you plan your composition before actual observation. Core Features: • Offline Celestial Database: 300+ bright stars, 110 Messier objects, 30 selected NGC objects • Local calculation of horizon coordinates (azimuth / altitude) for any moment within the next 72 hours • True field simulation for telescope + eyepiece, to judge if a deep-sky object fits entirely in the frame • Non-AR observation compass, using gyroscope and compass to aid target pointing • Observation list, sorted by best viewing time with completion tracking • Optimal viewing window calculation: rise/set/transit, lunar interference, twilight times • Camera sensor field simulation for astrophotography composition • Star Hopping: step-by-step jumping from bright stars to faint targets • Custom target input: manually enter RA / Dec or import temporary targets • Night red-light mode to preserve dark adaptation Starfinder uses no camera, loads no online content, and renders no full-sky panorama. All calculations are performed locally, making it ideal for field observation, astronomy education, and deep-sky photography.