A Jovian moons monitor in the form of a 4x1 phone home screen widget, ideal for quick reference and observation planning.
The widget provides the positions of Io, Europa, Ganymede and Callisto relative to Jupiter, plus Jupiter's central meridian and time to a next Great Red Spot transit.
The view of the moons can be flipped to accommodate various optical configurations.
After installation, a splash comes up with instructions and an About button. Please appreciate that widgets cannot be moved to external memory card.