Generating a delayed pulse of 0,5sec with one 555 timer upon powering up the circuit

In the link below, this circuit I found is what I needed. Only the length of the pulse and the delay are not what I want.

When I want just 0.5sec before pin 3 is up and the pulse duration I want is also 0.5sec, can someone tell me how big my resistors and capacitors must be? Or can someone tell me how I can calculate this?

My source power is 16 Volts I have already found 555 timers that can operate with 16 Volts, so thats not the problem.

When someone has another idea with two 555-timers, or something else that does the same, it's also OK.

Thanks

Circuit I need with wrong delays