The upper observatory tower has been extensively modified.
—Original structure reinforced with corrosion-resistant high-temperature alloys —Low-voltage, long-duration internal power supply added: probably radiological —Sensors and digital computers installed
These changes probably occurred more than a thousand years after the observatory's original construction.
Assessment: the observatory was repurposed as an anchor for a long-term monitoring station. The builders expected the station to be abandoned, so left it completely automated.
Recommend entry and data retrieval.