The Head of the Charles Regatta oper­ates sev­eral redun­dant tim­ing sys­tems. A high-speed photo-finish cam­era records a stream of 1-pixel-wide images across the start­ing line, which are dis­played on the screen as a hor­i­zon­tal strip. Here, one of two very capa­ble oper­a­tors zooms in and man­u­ally selects the pixel that best rep­re­sents the lead­ing edge of each boat, which assigns it an offi­cial start time.