design firing circuit for thyristor

The supply is 220v 50Hz ac.I need 80V DC output voltage .For this i need to fire the thyristor at 80

degree.The main problem is to fire the thyristor at 60 degree .please sugest me the firing circuit.
for half wave controlled rectifier
Vdc=Vm(1+cost)/2*pi
here t=firing angle
Vm=maximum ac voltage
Vdc=output DC voltage

So for Vdc=60V ,Vm=1.414*220=311
t=?
the required firing angle would be 80 degree