  The history of the isoptic curves goes back to the 19th century, but nowadays
the topic is experiencing a renaissance, providing numerous new results and new
applications. First, we define the notion of isoptic curve and outline some of
the well-known results for strictly convex, closed curves. Overviewing the
types of centered trochoids, we will be able to give the parametric equation of
the isoptic curves of hypocycloids and epicycloids. Furthermore, we will
determine the corresponding class of curves. Simultaneously, we show that a
generalized support function can be given to these types of curves in order to
apply and extend the results for strictly convex, closed curves.
