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Labsphere Type C Moving Mirror Goniophotometer

Labsphere Type C Moving Mirror Goniophotometer

The Labsphere type C moving mirror goniophotometer is a large format mirror goniometer which brings the benefits of C-type photometry in a full size package. Ideal for measuring almost any size of lamp or luminaire, from small lamps to large fixtures, indoor luminaires and outdoor luminaires. The moving mirror motion system satisfies the requirements of IES LM79-08.

In a type C motion system, the device under test is held facing vertically up or down, and does not tilt during a scan. This maintains precise thermal heat transfer paths during the scan and is a requirement of IES LM79. Instead, either the photometer cell moves in an arc about the sample (as per our standard type C system), or (as is the case here) a mirror rotates about the sample and reflects the light to a photometer cell placed in the photometric far-field.

A further advantage of the type C motion system is the ability to scan the device under test over 360° of azimuth - meaning that you obtain the complete light output measurement over all angles in a single scan. In comparison, type A and B goniometers require that the sample is flipped over if you need to obtain both forwards and backwards going light.

The recommended maximum sample size is 1.2m wide by 60cm deep, which corresponds to the popular standard ceiling fitting package.

The goniometer mirror rotates at 6 RPM and has an angular accuracy of < 0.01°.The system positional accuracy is ± 1mm.

The type C moving mirror goniophotometer requires a relatively large photometric dark room. We recommend a room which measures 9.1m wide by 12.2m long by 4.6m high, although it may be possible to install the system in a smaller room. Please speak to Pro-Lite for assistance with designing your photometric laboratory.

Measurement parameters include:

  • Luminous intensity (peak candelas, candelas versus angle)
  • Total luminous flux (lumens)
  • Beam angle
  • OPTIONAL: power consuption (Watts), luminous efficacy (lumens/Watt) & power factor
  • Charting functions: polar intensity in user-defined C-plane/s

Data export: industry-standard IES photometric file format; delimited text; Excel


  • Colour uniformity measurement
  • Selectable points measurement scans
  • Relative photometry measurement
  • Edison base bulb mounting fixture
  • Detector spectral correction
  • NIST traceable power measurement
  • NIST traceable calibration sources
  • Thermocouple integration
  • Temperature logging
  • Remote monitoring and control
  • IES LM-79 automated test protocol
  • DC power supply, 500 W
  • AC power supply, 1200 W
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