Ocean Optics SpectraSuite - Manual (Page 109)

7: Processing Menu Functions
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The Photometry table is described below:
Attribute Meaning
Source The absolute irradiance source you selected in Step 3.
Observer The type of observer you chose in Step 5.
Steradians
A unit of measurement used to describe the solid angle of a cone from the surface
of a sphere to the center of the sphere. It is a solid angular measurement used
when calculating illumination. The Lumens value is divided by the Steradians value
to obtain Candela.
Area (m^2) The light collection area per meter squared.
Lumen
The lumen value. A lumen is a “light watt.” Lumens are calculated as the absolute
spectral response of the human eye.
Lux
The lux values. The lux value is obtained by calculating the lumen per square
meter. Lux is also called a meter candle.
Candela The luminous intensity of the sample, based on international standards.
PAR
(µm/photons)
Photosynthetic Active Radiation. The number of moles of photons between 400 --
700 nm measured by absolute irradiance. To vary the 400-700 nm range, you can
specify the moles of photons range using
New Energy, Power, Photons .
PAR (µmol
photons/m
2 S)
Photosynthetic Active Radiation measured in terms of collection area and time.
X-axis Units
This menu item allows you to select the units for the x-axis on the spectrum graph. Choose from
Gigahertz, Microns, Pixels, Raman Shifts, Nanometers, and Wavenumbers. The default value is
Wavelength (nm).
Unit Preferences
Selecting Processing | Unit Preferences displays the Unit Precision Editor, which allows you to set the
precision reported for various units of measure.