The Pilkington Sun Angle Calculator (SAC) is a practical tool for architects and designers, offering a straightforward way to determine solar geometry variables essential for architectural planning. 

Originally known as the LOFSAC, it has been reintroduced and is favoured for its accuracy and simplicity. The SAC includes sunpath charts for various latitudes, a profile angle overlay, an altitude cursor, and assembly hardware.

Pilkington, now the owner of the tool, grants reproduction rights to the Society of Building Science Educators. 

While the instructional manual is online, additional resources for daylight availability overlays are referenced in Fuller Moore's book on architectural daylighting.