PHD2 2.5.0 for Mac could be downloaded from the developer's website when we last checked. We cannot confirm if there is a free download of this app available. The software lies within System Tools, more precisely Device Assistants. The actual developer of this free Mac application is Open PHD2 Guiding.
From the developer:
PHD2 is telescope guiding software that simplifies the process of tracking a guide star, letting you concentrate on other aspects of deep-sky imaging or spectroscopy.
Main features:
- Extensive support for commonly-used equipment.
- Easy upgrade/co-installation with PHD1, including many new features.
- Extensive online help and responsive product support.
You may want to check out more software for Mac, such as iPhoneDisk, SpaceReporter or iSurveill, which might be related to PHD2.