LOS ANGELES, United States (AFP) — Darth Vader’s helmet from “The Empire Strikes Back” is among a vast collection of coveted Hollywood treasures going under the hammer next month, with experts predicting it could fetch nearly $500,000. The mask and helmet is one of only a handful worn by actor David Prowse, who played Luke Skywalker’s nemesis and — spoiler alert — father on-screen in the 1980 “Star Wars” blockbuster, making them the “holy grail” […]