A yellow / orange beam, (593.5nm), of about 8 mW is easy to see, and is really close, maybe about as bright as a "real" 5mW green beam, so, if you have no fog, you must be within about 4-6 feet of behind the laser, or it must be very dark and your eyes need to be adapted to the dark tp see from about 10 or so feet. So, at a 90 degree view the beam will disappear if you are not near enough in dry clean air. -Glenn