Re: Sri Navgraha question..
As far as I know shukracharya is not Asura (I am not sure but), he was son of sage just like brihspati.. shukracharya wanted to become Guru of Devas but lord Vishnu make brihspati the Guru of Devas, also there is one incident in which shukracharya went to father of brihspati to learn Vedas but he didn't like his favorism towards brihspati..
So due to this all scenario shukra started hating lord Vishnu and become Guru of daityas (asuras) and help them with his mrit Sanjivani Vidya in the battle between Sura and asura
But as he is Guru of asuras then he is also Asura this should not be true as per my opinion shukracharya is deva whose task is to teach asuras..
But I haven't studied Purana much so I am not sure
Aasato ma sat gamay
tamaso ma jotirgamay
(Bring me from asat to sat, bring me from darkness (ignorance) to light (knowledge), bring me from death to immortality)
Om Namah Shivay
Om Vishnave Namah