Help! Picoscope/Astable Problems

I have a 555 astable like below and want to measure the frequency using picscope which I believe to be an oscillopscope. The circuit is on a breadboard and I was wondering if anyone knew where to connect the crocodile clips to the astable to measure its frequency?
**broken link removed**


Thanks for your help.
Steve

Clip the ground pin on the negative terminal and the other one on pin 3

Cheers Mike. Top Stuff.