ruby-sphere-0.4.2 released

ruby-sphere is an application to calculate apparent positions of stars with a moderate accuracy. We are pleased to announce the sixth alpha release, ruby-sphere-0.4.2 with more flexible time specification and availability of specifying a point on the sky with azimuth, elevation, and time.

The goal of ruby-sphere is to to provide an easy way to plan astronomical observations. Ruby version 1.8.x is required. Gnuplot is required to plot visibility maps.