Id say those are about ready my friend.
This subject is very much based on opinion but there is a certain amount of scientific fact that is relevant to us growers.
after the plant has been flowering for a certain period, the trichome production reaches a peak of about a week, this is known as the ripening period. after this time, the properties of psychoactive compounds begin to break down you want to harvest the plant at the optimal point in time. some would say when 1/3 of the pistils turn orange. some like to be more exacting in their methods by examining with a magnifying glass their plants in many areas to inspect the shape and color of the trichomes. the trichomes should be milky to light brown in color, these are mature trichomes. do not harvest when the trichomes are still see-through, these are immature trichomes. also the shape of the trichome should resemble a mushroom.
well i think ive said all I can on this subject I hope this helps. happy harvesting Luke.