 An astronomy app designed to help observers locate and follow Messier objects and the major planets from any geographic location. The user can save their observing latitude, longitude, and UTC offset, then enter a date, time, and viewing direction to see which objects are above the horizon and where they appear in azimuth and altitude. The app includes interactive sky plots, object selection, short-term trajectory plots covering approximately ±4 hours, yearly position plots sampled throughout the year at a fixed 21:00 UTC reference time, and catalogue/detail views for Messier objects. Planetary positions are calculated dynamically from orbital elements, while Messier objects use stored celestial coordinates, allowing both deep-sky and Solar System observing tools to be combined within a single application. This is not high-precision astrometry but suitable for general observational pointing. |
A 3D visualization tool for exploring chaotic attractors on the HP Prime calculator. Users can interactively view and manipulate eight well-known attractors, including Lorenz, Roessler, Halvorsen, and Aizawa. The app computes trajectories using the Euler method and displays them in a fully interactive 3D plot, allowing rotation, zoom, and pan.