What is the relation between criminology and penology?

Penology is actually a branch of criminology. Criminology studies crime - theories, explanations, victims, criminal justice systems, forms of punish and deterrence etc. Penology studies the specific areas of prisons and the incapacitation of offenders. The main areas for Penology is Prison system management, programmes etc. Criminology includes a small amount amount of prison study in general as part of the general course. If you have a degree in Criminology you can still do Penology post grad and vice versa