Moon Phase & Illumination Calculator
Precision synodic lunar cycle calculation & observing guide
Calculate the exact phase, illumination percentage, lunar age in days, and upcoming full moon dates for any day in history or future.
Age on Other Planets Calculator
Calculate your exact age and birthdays across the Solar System
Computes your age in planetary years for Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune based on their orbital periods.
Telescope Magnification & Optics Calculator
Calculate magnification power, exit pupil, and Dawes’ resolution limit
Determine the optical limits of your telescope and eyepiece combinations, including Barlow lenses and focal ratios.