[mp8]

That's surprising. I went there recently, and you aren't permitted to bring any electronic devices whatsoever - you have to leave them in a locker and then take a ~30 minute bus ride to the telescope.

They're also very strict about checking: you have to go through two different x-ray machines to check you didn't sneak any electronics through.

[janekm]

Perhaps the no-devices policy was introduced after the interference issues were encountered?

[SiempreViernes]

No, the no devices policy would have been there from the start, its as basic as forbidding open flames at a petrol station.

The need for X-ray machines due to tourists ignoring the ban is a more likely development.

[guenthert]

Are those truly x-ray machines? Not just magnetic coils? Seems overkill and I'd object to being exposed to ionizing radiation just for the purpose of validating my claim that I don't carry any electronic communication devices.

[janekm]

It's actually a pretty standard setup in China anyway... Pretty much anytime you go onto an inter-city bus / train or into a crowded space (museum / exhibition centre) you will go through a metal detector and your bag through an x-ray machine. So it makes sense that they'd just use the standard setup that the local security company would be used to.

[yorwba]

Most likely it's X-rays for your stuff and metal detectors to make sure you're not trying to smuggle anything past the X-ray machine.

[atr_gz]

No, it wasn't there from the start. The no electronics policy only started within the last two years. I know someone who has been there and has the pictures on her phone.