Primary Direction Explorer (aka PDExplorer or simply PDE) is a freeware astroprocessor designed especially for exploring astrological Primary Directions. Along with regular set of features any astroprocessor has to implement, PDExplorer considers celestial body's oblique and in mundo longitude. These parameters are of some interest in primary direction analysis, though they are not easy things to calculate. Due to calculation difficulties many astrologers do not use Primary Directions in their practice.