Need a scheduled reboot of my LTM

I am planning for a scheduled restart of my Big IP LTM (ver: BIG-IP 12.0.0 Build 3.0.654 Hotfix HF3) every Friday midnight at 12.30.

I am trying to accomplish this by executing the below command:

crontab -e

30 0 * * 6 /usr/bin/bigstart restart

But it does nothing. Could you please help?