Start times for stops on subway line 10 in Beijing

When does line 10 Shaun Jing subway start in the morning? I have to be at the airport for a 7:30 flight. Any idea as to where I can get the exact information? On this site it shows where the subway starts at 5:20, but I am under a time constraint. I was ripped off by a taxi for twice the cost on my journey into BJ.