Handheld Radiometer


Handheld SpectroRadiometer for NIST traceable light measurement from 350-1100nm with <1nm spectral resolution. UV and near-infrared ranges are optional. Handheld-Radiometer measures irradiance, illuminance, xy chromaticity, dominant wavelength, CCT, CRI, the complete spectral distribution of all light 350-1100nm, and much more! The handheld system incorporates research-grade BLUE-Wave spectrometer optics. It has an 8″, high performance Android touchscreen interface that’s both ergonomic and user-friendly. System comes with pre-installed StellarRAD software and calibration, direct attach SMA-coupler, CR2 Cosine Receptor, IRRAD-CAL irradiance calibration, and certificate. System charging adapter and USB key included.



The StellarRAD™ Series 3 is a rugged, turn-key solution for portable light measurement.  This handheld radiometer is an easy-to-use research-grade spectrometer for field testing of lights with no additional setup required. The NIST traceable system can measure spectral Irradiance & Illuminance, CCT, xy chromaticity, CRI, PAR, and much more!

Compared to other handheld colorimeters, the StellarRAD utilizes a research-grade spectrometer with <1nm spectral resolution, making these instruments the first choice in reliable testing, field demonstrations, installations, R&D, and quality control.

  • Reliably measure light output in Lumens/m^2 (Lux), Watts/m2, PAR, PPFD, and Footcandles
  • 1931 CIE Chromaticity Diagram for xy Chromaticity, Dominant Wavelength, Purity, Correlated Color Temperature (CCT), & Color Rendering Index (CRI)
  • Includes NIST Certificate of Traceability and delivered with all calibrations preloaded ready to use
  • UV upgrades (250-1100nm) available; includes UVa, UVb, UVc, ratios, & power for $500
  • Includes Solar Monitoring App with solar and grow light classification
  • Add lens, aperture, and collimating tube attachments for increased functionality
  • ColorWiz Handheld Colorimeter and ChemWiz Handheld Spectrophotometer now available!


StellarRAD Technical Specifications

Sensor: BLUE-Wave spectrometer with 2k pixel detector
Spectrometer range: 350-1150nm (Optional UV @ 250nm)
Spectral Resolution: <1nm
Measurement Range: 0.05-400k Lux/ 0.25-1600W/m^2
Receptor Type: Cosine corrected for Irradiance
Integration time: 10ms to 60s
Digitizer Resolution: 16bit
Optics: Research Grade Crossed Czerny Turner
Wavelength Accuracy: <0.25nm
lluminance Accuracy: +/- 5%, NIST Calibrated
Color Accuracy: +/-0.001 (reference standard lamp)
CCT Accuracy: +/- 2%
Tablet Specs: Android
Software included: StellarRAD App

StellarRAD Software Interface

Take a tour of our StellarRAD Pro software delivered on our new series 3 StellarRAD Handheld SpectroRadiometer. This quick demo shows how to connect to the device, modify Device Settings (integration time, scans to average, smoothing), take a dark reference, capture sample data, and save and review spectral data! This quick demo is just the beginning of the spectrum as the StellarRAD also features Episodic Data Capture, PDF reporting, and much more!

Light Hurricane Demo

The intuitive StellarRAD software interface allows system control and collection of advanced light measurement parameters such as spectral irradiance (Watt/m²), illuminance (lumen/m²), & PAR (Photosynthetically Active Radiation). Colorimetric analysis such as CRI (Color Rendering Index), CCT (Correlated Color Temperature), xy chromaticity, and much more are included. Capture snapshots or continuous mode spectra. Easily save and export your data and full spectral graph as an .IRR text data file, screenshot, and/or PDF report with all parameters listed.

StellarRAD Applications – LEDs, Luminaires, Solar, Displays, Grow Lights, & Lasers!

Any Light Emission

What better way to demonstrate a handheld radiometer than to measure a candle flame!  Any type of light emission can be measured by pointing the StellarRAD’s cosine receptor toward the light source, setting the best exposure time and system settings, and pressing capture.

White LED Color

White light, cool white, warm white, incandescent white, LEDs… Just how many different white lights can there be? The StellarRAD automatically calculates Correlated Color Temperature (CCT) and Color Rendering Index (CRI).  Easily distinguish and compare white LEDs.

LED Quality Control

With so many LEDs being manufactured overseas, you need a reliable instrument to test your incoming products. As a manufacturer or product integrator, checking the power and wavelength for accuracy of specification and/or consistency is important. The StellarRAD is the instrument for you.

ColorWiz Handheld Colorimeter Upgrade

Now available! ColorWiz Handheld Colorimeter allows users to add an integrated halogen light source, reflectance accessories, and the powerful ColorWiz Pro App software to their StellaRAD making real-time color measurements quick and easy. Acquire full spectrum analysis and research-grade colorimetry of solids and powder samples! Measure advanced color parameters such as CIE L*a*b*, RGB, Chroma, Hue, Luminosity, SRM, Lovibond, and EBC. Save a dE color reference & calculate color differences.

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