The road that snakes towards the observatory's security entrance seems to conspire with the surrounding hillsides to hide the facility below, obscuring the site in an invisible layer of insignificance - except for the dishes that give away that something technologically advanced is taking place in this unlikely corner of the country.
The work that happens at HartRAO which is a facility of the South African Radio Astronomy Observatory is critical, however the site plays a big role in ensuring the navigation systems used by people all over the world are accurate and reliable, while also contributing to advancing our understanding of the universe.
It was during a recent tour of HartRAO that TechCentral learnt that Johannesburg "bobs up and down" by around 30cm each day along with the rest of the planet at between 20cm and 40cm. These 'solid earth tides", which cause the Earth's mantle to ebb and flow like oceanic tides, are due to the gravitational forces exerted on the planet by the moon and sun.
Since this changes the position of a point on Earth's surface, albeit only slightly in the grand scheme things, it has a significant impact on the accuracy of systems like GPS.
HartRAO is unique in that it is one of only seven such stations in the world known as "fundamental sites". These are locations where all four of the major space-geodetic techniques are collocated.
