RACING – SLALOM AND SUPER G Race events are increasingly being scheduled at night. Advantages include eliminating inconsistencies caused by changing sunlight that affects temperature, snow texture, and visual perception. The challenge has been to create lighting that fully illuminates the course while not interfering with visual perception. (See “Technical Elements for Event Lighting”) Since high intensity lighting can blind a skier, courses have been downlit , meaning lamps are faced downhill at the racers back. Obviously, this can cause shadowing in front of the skier’s progress down the course. A review of FIS guidelines specifies that athletes should not be blinded by lighting, but downhill shadowing should also be eliminated. Lighting physics forecloses this combination of objectives. The only way to eliminate forward shadowing is to up-light; face lighting uphill.
Achieving the desired result requires a plan that alternates lighting infrastructure along the slalom track. This “zig-zag” should focus at the centerline from both sides going across the course, uphill, and downhill. Alternatively, light can be projected from high-mast poles that can provide uniform illumination with direct top-down projection. Advantages to high-masts include removing forward shadows and smooth light distribution. Disadvantages are a propensity to “flatten” the course
appearance, much like flat sunlight, and over-projection, causing light pollution. High- mast infrastructure is more expensive than conventional 25 to 40-foot (7.62 to 12.19m) poles. If the resort already has high-mast lighting using metal halide fixtures, greater energy efficiency can be achieved by upgrading to high-intensity LEDs or Snow-Bright™ magnetic induction floods. High-masts are typically 60 feet (18.28M) or higher. Some important considerations include making sure fixtures are suitable for snow and ice, the LED drivers should minimize high-frequency flicker, ballasts (drivers) should not generate high-pitch harmonics that can disturb bats and canines. Research whether the LED uses Pulse Width Modulation (PWM) for controlling intensity. This is specifically linked to the flicker rate. High-frequency flicker is a fundamental LED characteristic. It generally related to the alternating current hertz which is 60 Hz in the U.S. and 50 Hz in Europe and other regions. Regarding conscious vision, a 60-cycle flicker can be perceived by most people and causes strobe effect. Doubling this to 120-cycles is incorrectly believed to exceed human perception, but can actually be more problematic for high-speed sports because strobing still impacts depth perception and timing.
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