Landscape Lighting optical parabolic A dish consisting of a light bulb and reflector. Lamps such as the popular MR-16, PAR 20 and commonly used, PAR 30 and PAR 38 lamp and integrating parabolic shape in a single package. These types of lamps are mainly in low voltage and 120 voltage line applications, and are available in two versions incandescent and metal halide. A typical application is shown in Figure 1, where spotlights are used for various trees and shrubs along a light path.
Figure 1 - Spotlights used for trees and shrubs along the path of light.
More sophisticated commercial applications typically use parabolic optical packets created by the manufacturer of the fixture. In Figure 2, the apparatus in the ground with metal halide light spot are used to light some of the statues, trees and mast in a memorial 9 / 11. Custom reflector designs, and a lamp as an E17, T6 or T4, are used. The reflector is a parabolic shape with the most common mirror finish. When the arc tube of a MH lamp is positioned at the focal point of the parabola, the light rays are emitted in a parallel beam reflector, creating a spot. Arc lamps smaller tubes to focus more light at the focal point, producing a narrower model spotlights.
Figure 2 - Spots of light used for trees, statues and mast 9 / 11 Memorial.
Photo courtesy of the architects Cap Brad Allred.
Different types of lamps placed in the same parabolic reflector to produce different results because of their size arc tube. For example, a 100W E17 MH lamp has a much smaller arc tube of an E17 175W, even if their bulbs are the same size. Lamp 100W E17 will produce a spot much closer with a greater concentration of light or candle power beam center. Figure 3 illustrates the difference between these two fires. Be careful when changing lamp light values in the original package to simulate a photometric light power different from the one originally tested and recommended by the manufacturer of the fixture. The results in the field can not be as expected. The light can be bright or dark and not as heavily concentrated in both space or flood model as needed.
Figure 3 - 
E17 100W (top) and 175W (bottom) arc tubes.
A lamp power and light (lumens) it produces, made by the efficiency of the reflector to produce the luminous flux or lumen size parabolic optical system. Today, new low-wattage lamps and metal halide, such as T4 or 20W BT5 have very small arc tubes that can produce powerful narrow beam headlamps. They perform significantly better on a maximum of candelas per watt basis of their close higher power. A typical location used by optical ALLSCAPE ®? in their product into the soil with a 20W lamp BT5 Philips produces 46,999 candlepower beam center relative to the low light intensity 40,516-center beam generated by a lamp 39W T6. BT5 the angle of the beam is narrower and more focused to 6 °, 8 ° to the T6.
When a narrow beam optics (below 10 ° beam) is required, best results will come from the lamp with the smallest arc tube for a given parabolic reflector. A narrow beam illuminates a greater distance, allowing for larger objects in the landscape (trees, columns and flagpoles) to illuminate more efficiently.
An optical spot requires the arc tube lamp to be placed at the focal point of the parable. What happens if not? Moving the arc tube has a small distance parables focus broadens, producing an optical flow. Movemen The arc tube.
Posted on July 31, 2010.
