PHD2 is the second generation of Craig Stark's original PHD application.  PHD became a fixture of the amateur astronomy community with more than a quarter million downloads.  From its inception, it has successfully embraced three seemingly conflicting objectives :

Since the original code was released to open-source in 2013, it has been completely overhauled to make it more extensible and supportable.  With the restructuring in place, substantial new features and capabilities have been added, many of which focus on helping you achieve better guiding results.  Users of PHD2 can be confident it will remain committed to the three objectives that made the original application so successful.