star

What do you say to the ppl who argue that using the star position and palm reading to foretell opportune and disadvantageous times of a year, month and day is a tool to be used and not in any way the reason for the event. They argue they are not arguing against Gods will and power ( takdir )  over events in a persons life but just making judgements on what has already been decided. A sort of roadmap.They argue the stars are under the control of Allah and the knowledge of astrology is given by Allah to benefit mankind. They argue astrology makes life easier by giving suggestion on things to look out for based on probable chances of events occuring / human characters strength and weakness / opportune time etc. These  educated guesses based on star positions and palm reading minimizes the bad effects stars have on people and enhances the good effect. This is the argument given to me by a person who belives in Vedic astrology . What should be my answer? I need to know about the matter more to make a valid argument against it. No matter how self serving rationalizing the above sounds I need a good enough argument to approach and rectify this person who is close to me.Also what is the islamic view on wearing stones .... please clarify the use of stones ... beliving it has benefits other then ornaments ( for good health / fortune etc ) somehow eliminate the bad effects etc.What is the sunnah  say about wearing rings and stones ?thanks for your time and effort.Zahed