Frosty Drew Observatory & Sky Theatre provides a collection of small tools which allow you to make a variety of astronomical calculations. We offer maps of the sky, the phases of the Moon as well as computational tools. From time to time we add whatever seems appropriate. As a working limit, we have chosen not to require more than four items for any calculation (if you will accept the notion that a latitude and a longitude together form is a single item - a location). We don't produce more output than will conveniently occupy a pop-up message box.

These tools should not be relied upon for extended time periods or for high precision work. In many cases, the techniques give only approximate answers by ignoring minor factors such as the disturbances of the planets (perturbations) and slowly changing variables such as the tilt of the Earth's orbit. Round off errors accumulate when times deviate greatly from the present.