Mean Spherical Candlepower (MSCP) is a measure of the average luminous intensity of a light source in all directions (spherical). It is expressed in candelas (cd) and is used in measuring light sources such as incandescent bulbs, car headlights, and signal lights .
How is MSCP calculated?
MSCP is the average candela value over 360 degrees , rather than just in a specific direction. This is especially useful for non-directional light sources , such as spherical lamps.
The formula for MSCP is:
whereby:
- Lumen (lm) = total light output of the light source.
- 4π = the total spherical space in which the light propagates.
For example, a 1000 lumen lamp has an MSCP of about 79.6 cd (since 1 lumen = 1/4π candela in an isotropic source).
Why is MSCP important?
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Comparison of light sources
- MSCP helps determine the effectiveness of different lamps, especially if they emit light in all directions .
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Automotive and signal lights
- Automotive and aircraft lighting are often rated for MSCP because light distribution in all directions is crucial.
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Lighting technology
- MSCP is used in the evaluation of spherical light sources , such as incandescent bulbs and some LEDs, where the light intensity is measured within a uniform spherical shape .
MSCP vs. other light measurements
| Mate | Meaning |
|---|---|
| Lumen (lm) | Total light output of the source. |
| Candela (CD) | Light intensity in a specific direction. |
| MSCP | Average candela value in all directions. |
MSCP is less used in modern LED lighting , because LEDs often have directional lighting and candela measurements per beam angle are more important.
Summary
- MSCP = average luminous intensity (candela) of a light source in all directions .
- Useful for spherical light sources, automotive lighting and general light measurements.
- Not suitable for LEDs with a focused beam , where candela and lumens are more important.