I would like to clarify about Raja and Hatha yoga in respect to their dependance and indepence from each other. In recent articles I have discussed the supportive relationship between the two forms of yoga. It is true these two forms of yoga do work well together, as indeed I explained. This gives a rather one sided view to the topic.
Raja yoga originally came before Hatha yoga, therefore it is possible to explore Raja yoga without Hatha yoga. Its true hatha yoga has many benefits and can be practiced without Raja yoga, although Hatha was designed to support and/or prepare for raja yoga. Its just that most people who want to explore raja yoga would greatly benefit combining raja and hatha yoga.
Should you only want to practice hatha yoga there is no need to feel like you should explore raja yoga.