The SPK package consists of a library of ANSI C functions plus demonstrations for the equatorial and altazimuth cases and an end-to-end testbed program for diagnosic purposes.

The library is a set of just three ANSI C functions that provide low-level support for the pointing and tracking components of a TCS. The positional-astronomy aspects are handled using tools from the IAU SOFA library, while the algorithms that predict the telescope mount angles are from Wallace P.T., 2002, A rigorous algorithm for telescope pointing, Advanced Telescope and Instrumentation Control Software II, edited by Lewis, Hilton. Proceedings of the SPIE, 4848, 125.

It should be noted that although SPK contains an internal pointing model that takes into account a core set of instrumental effects, this is merely a template for the more detailed model that will be needed if the telescope's pointing capabilities are to be fully realized. Serious use of SPK consequently involves acquiring a proprietary modeling tool, such as TPOINT. But as a stopgap, a rudimentary free-standing application is supplied with SPK that fits pointing-test data to a very basic six-term model.

The user guide is spk.pdf and the files are in spk.zip