Introduction

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 :

For the beginning or casual imager, to deliver ease of use and good guiding performance "out of the box".
For the experienced imager, to deliver sophisticated guiding algorithms, extensive options for tuning, and broad support for imaging equipment.
For all users, to consistently exhibit a commercial level of quality while being available free of charge.

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.