Abstract: An apparatus for assisting in finding an article such as a golf ball (2) includes a housing (3) containing a laser diode (4) for radiating an excitation beam (5) in the UV or IR bands. The apparatus has a receiving lens (9) for receiving a return beam (8) sent back from the golf ball (2) by the fluorescent coating on the ball. The return beam (8) falls on a photodiode receiver (10) after passing through two filters (11, 12) which filter out incident sunlight. Processing means (15) processes the signal received by the receiver and drives an indicator (18) in the form of a beeper or flashing light which indicates that the golf ball (2) has been sensed by the apparatus.