MQ-303: Line Quantum with 3 Sensors and Handheld Meter

Apogee line quantum sensors measure a spatial average of PAR (Photosynthetically Active Radiation). The MQ-303 has a separated sensor bar with 3 sensors connected to a hand-held meter via cable.

  • Product Name:Line Quantum with 3 Sensors and Handheld Meter
  • Item No.:MQ-303
  • Manufacturers:Apogee
  • Country of Origin:USA

Apogee line quantum sensors measure a spatial average of PAR (Photosynthetically Active Radiation). The MQ-303 has a separated sensor bar with 3 sensors connected to a hand-held meter via cable. The sensor housing design features an integrated bubble level and is fully potted making the sensor weatherproof. Typical applications include PPFD (Photosynthetic Photon Flux Density) measurement over plant canopies in outdoor environments, greenhouses, and growth chambers, and reflected or under-canopy (transmitted) PPFD measurements in the same environments. Quantum sensors are also used to measure PAR/PPFD in aquatic environments, including salt water aquariums where corals are grown.

The meter has a sample and log mode, and will record an integrated daily total in mol m-2 d-1. Sample mode will record up to 99 manual measurements. Log mode will power the meter on/off to make a measurement every 30 seconds. Every 30 minutes the meter will average the sixty 30 second measurements and record the averaged value to memory. The meter can store up to 99 averages, once full it will start to overwrite the oldest measurement with new ones. An integrated daily total will be recorded from the 48 averaged measurements (making a 24 hr period). Sample and log measurements can be reviewed on the LCD display or by downloading the data to a computer, however, the integrated daily total can only be viewed by downloading the data to a computer. Downloading data to a computer requires the AC-100 communication cable (a standard USB cable will not work) and ApogeeAMS software.


Calibration Uncertainty    ± 5 %

Measurement Repeatability    Less than 1 %

Non-stability (Long-term Drift)    Less than 2 % per year

Non-linearity    Less than 1 % (up to 3000 µmol mˉ² sˉ¹ )

Response Time    Less than 1 ms

Field of View    180°

Spectral Range    410 nm to 655 nm (wavelengths where response is greater than 50 % of maximum)

Directional (Cosine) Response    0.06 ± 0.06 % per C

Temperature Response    ± 5 % at 75 ˚ zenith angle

Operating Environment    0 to 50 C, less than 90 % non-condensing relative humidity up to 30 C, less than 70 % non-condensing relative humidity from 30 to 50 C, Separate sensors can be submerged in water up to depths of 30 m

Meter Dimensions    126 mm length, 70 mm width, 24 mm height

Sensor Dimensions    500 mm length, 15 mm width, 15 mm height

Mass    300 g

Cable    2 m of shielded, twisted-pair wire with santoprene rubber jacket (high water resistance, high UV stability, flexibility in cold conditions), additional cable available

Warranty    4 years against defects in materials and workmanship