Protection of SAAO observing site against light and dust pollution

The South African Astronomical Observatory (SAAO) observing station near Sutherland, Northern Cape in South Africa, is one of the darkest sites in the world for optical and IR astronomy. The SAAO hosts and operates several facilities, including the Southern African Large Telescope (SALT) and a number of international robotic telescopes. To ensure that the conditions remain optimal for astronomy, legislation called the Astronomy Geographic Advantage (AGA) Act, of 2007, was enacted. The Act empowers the Department of Science and Technology (DST) to regulate issues that pose a threat to optical and/or radio astronomy in areas declared Astronomy Advantage Areas in South Africa. For optical astronomy, the main challenges are those posed by light and dust pollution as result of wind energy developments, and petroleum gas and oil exploration/exploitation in the area. We give an update of possible threats to the quality of the night skies at SAAO, and the challenges relating to the AGA Act implementation and enforcement. We discuss measures that are put in place to protect the Observatory, including a study to quantify the threat by a planned wind energy facility.