Frederik Botha and Yvonne Jacobs set up the solargraph stand on the Queen’s House roof, overlooking Greenwich Park. Supplied by Frederik Botha. At the top of the Tulip Stairs, we stepped out onto the roof of the Queen’s House. Two weeks earlier, with permission from Royal Museums Greenwich, Frederik Botha and I had set up seven tiny pinhole cameras to photograph the Sun’s path over Greenwich Park. After a spell of wind and rain, we were keen to see how they had fared. The fir