GUIYANG — Measures to limit the number of visitors at the site of the world’s largest single-dish radio telescope were adopted to cope with a tourism boom during the seven-day National Day holiday.

Guests at a viewing platform of Five-hundred-meter Aperture Spherical Radio Telescope (FAST) have been limited to 2,000 people per day, according to the publicity department of Pingtang county in Southwest China’s Guizhou province, where the giant telescope is located.

Although the access to the viewing platform is free of charge, each visitor needs to pay 50 yuan ($7.3) for shuttle bus service. Since Sept 20, shuttle bus tickets have been available only through online booking.

Since its trial operation in 2016, FAST has found 44 pulsars, which can be used to conduct research on gravitational waves and black holes, and to help solve many other major questions in physics.

However, the tourist surge has stoked concerns that radio signals from electronic devices carried by tourists might compromise the telescope’s results.

Alongside the latest measures, the local government has also set up strict security checks to ensure no electronic devices are brought with when tourists enter the viewing platform.

FAST will start formal operation and open to Chinese astronomers in 2019.