This quick-start guide is intended for StellarNet customers wishing to use their calibrated spectrometer for radiometry.
- Make sure StellarPro and the StellarNet drivers have been installed and function properly – see Quick-Start Guide – Spectrometer Installation for additional details.
- Radiometry requires a calibration file to be loaded into StellarPro. Each physical configuration should have a unique radiometry calibration. Annual recalibration is recommended.
- If your instrument was calibrated for radiometry, you should receive a USB thumb drive with your calibration file(s).
- There should be a self-executable file named “MyCal-##########.exe” – The # will correspond to the spectrometer’s serial number and calibration type.
- Run the executable, or save the .CAL file to a safe spot that is easy to find on your computer.
- Open the StellarNet software by double clicking on the StellarPro icon
on your desktop to launch the application and then log in. - In the side navigation bar, click on the “Radiometry” app
and you should see a screen that looks like this:
- Confirm that your spectrometer has made a successful connection with the software.
- To load your calibration file, navigate to the “App Settings” and click “Load CAL”.
- A prompt will appear to find your calibration file. Navigate to and select the correct calibration file for your set-up.
- Click on the SCOPE tab in the Graph window. This will show you the number of counts (photons) the detector receives. You should see a spectrum of counts versus wavelength. This is where you will optimize your curve.
- The first goal is to increase integration time so that the amplitude of the curve reaches ¾ to 90% of the maximum (65536 counts).
- To adjust the integration time, enter the value in the “Device Settings” section of the “Acquire” bar. If the “*Int Time (ms)” is in RED click on the “*Int Time (ms)” to set the integration time.
- Saturation is when there is too much light. If you see a flat top for your curve, decrease your integration time or move your cosine receptor back from the lamp source.
- If you do not have enough light, you will want to increase your integration time.
- Below is more or less what you want to see – maximizing the amount of light being measured without saturation.
- To adjust the integration time, enter the value in the “Device Settings” section of the “Acquire” bar. If the “*Int Time (ms)” is in RED click on the “*Int Time (ms)” to set the integration time.
- You can further optimize your conditions by applying scan averaging (increases wait time – take integration time and multiply by scans to average) or smoothing. A smoothing value set to 3 and averaging set to 5 often gives nice results.
- Now that the curve is optimized, cover your light collecting accessory (sphere, cosine receptor, etc.) so that there is zero light detected by the spectrometer. If you are using a sphere with an internally mounted light source, turn off the lamp or remove the SMA fiber from the spectrometer and block the spectrometer’s SMA port.
- It is now time to take a “Dark” measurement.
This button will toggle between Dark Captured and Dark Released. See the tooltip for the time of the last capture/release. Left Click on the lightbulb icon to capture the dark after turning OFF light source. The captured dark will be stored and reloaded for the same spectrometer next time. Left clicking again will overwrite the previous dark. Dark Captured: 
Dark Released: 
- Uncover the light collecting accessory (or turn on your lamp/ insert the fiber if lamp is internally mounted in a sphere).
- View the spectrum on-screen. If it looks correct, you can switch to the Watts, Lumen, or PAR tab. Watts will provide you with the radiometric units while the Lumen tab will provide you with the photometric units that correspond to the geometry of your measurement.
- There are multiple sections included in radiometer mode, The “Data” tab includes the irradiance data as well and CRI, CCT, and other colorimetric values.
You can use the drop down menu to adjust the units from W/m2 to mW/cm2 (or other combinations). 
- This value in the corner is calculated from the area under the curve over a specific range. You can verify this range in the “App Settings” menu. Depending on the wavelength range of your instrument and your calibration file, you can adjust this range to fit your needs. Using the dropdown menu allows you to choose between VIS, UV, NIR, or a custom range. Note that photometric units (lumen, lux) have predefined ranges as they are based on the response of the human eye.
- If you have a CR2-AP, you can enter the value of the aperture in the “App Settings” menu. The CR2-AP is a constant aperture type – input the value on the bag.
If you have any questions please email them to support@stellarnet.us accompanied by screenshots to illustrate your concerns or visit our knowledge base for more detailed software information: https:// www.stellarnet.us/spectroscopy-knowledge-base/