Unihedron Sky Quality Meter with Lens - Narrow Field of View / USB Data Logging & Housing

Stock count is accurate & shown in real time.
- This item is out of stock.
- Sign up for back-in-stock alerts to be notified when this item becomes available (account login required).
- This item is out of stock.
- Sign up for back-in-stock alerts to be notified when this item becomes available (account login required).
Contiguous US / Lower 48:
Free shipping applies to orders over $50 using our chosen carrier/method. Faster paid options are available at checkout.
Alaska, Hawaii & US Territories:
Free shipping applies to many—but not all—products. Enter your ZIP code in cart or upon checkout to confirm options and costs.
International:
International orders do not qualify for free shipping. Shipping, duties, brokerage, tariffs, and taxes are the customer’s responsibility. Some items may be restricted due to export, size, or manufacturer limitations.
A USB enabled data-logging light meter for night-time sky brightness monitoring! An affordable meter for continual, connected or autonomous data-logging to measure sky brightness for astronomers and light pollution investigators. The "Sky Quality Meter" measures the brightness of the night sky in magnitudes per square arcsecond. Designed by Dr. Doug Welch and Anthony Tekatch
Uses:
- Measuring the night sky brightness during remote biological field experiments.
- Find out how good the night or site REALLY is.
- Compare the sky brightness at different sites quantitatively.
- Document the evolution of light pollution in your area.
- Set planetarium dome illumination to mimic the skies people are likely to experience elsewhere in the city.
- Monitor sky brightness through the night, night-to-night, and year-to-year.
- Determine which nights show the greatest promise for finding the 'faintest fuzzies'!
- Calibrate the effect of sky brightness on qualitative measures such as the Bortle Scale.
- Investigate how sky brightness correlates with the solar cycle and month-to-month sunspot activity.
- Help provide local ground truth for future sky brightness prediction with the Clear Sky Chart.
- CCD users can make a correlation between the SQM reading and when the background reaches some ADC level.
Features:
- Sky brightness reported in visual magnitudes per square arcsecond.
- Infrared blocking filter restricts measurement to visual bandpass.
- Sensor temperature, model number, and serial number are provided.
- Precision readings at even the darkest sites.
- Field-upgradeable firmware.
- Open protocol document.
Specifications:
- USB connectivity
- Included applications for reading data in Perl.
- The Half Width Half Maximum (HWHM) of the angular sensitivity is ~10°. The Full Width Half Maximum (FWHM) is then ~20°. The sensitivity to a point source ~19° off-axis is a factor of 10 lower than on-axis. A point source ~20° and ~40° off-axis would register 3.0 and 5.0 magnitudes fainter, respectively.
- Size 5.5 x 2.6 x 1.1 in.
- Maximum light sampling time: 80 seconds.
- Minimum light sampling time: 1 seconds.
- Specifications are subject to change without notice.
What you get:
- SQM-LU-DL unit
- USB flash drive containing the users manual, operation software (UDM), and example software. This can also be found online here.
- 15ft USB cable Battery-to-USB adapter with 6 AA cells and battery holder
- Calibration sheet indicates unit USB serial number, and calibration values
- Weatherproof housing
Useful Resources
- User Manual: SQM-LU-DL Instruction Sheet (PDF format)
- Frequently Asked Questions
- SQM Comparison Chart
Other Information
- Country of Manufacture: Canada
A USB enabled data-logging light meter for night-time sky brightness monitoring! An affordable meter for continual, connected or autonomous data-logging to measure sky brightness for astronomers and light pollution investigators. The "Sky Quality Meter" measures the brightness of the night sky in magnitudes per square arcsecond. Designed by Dr. Doug Welch and Anthony Tekatch
Uses:
- Measuring the night sky brightness during remote biological field experiments.
- Find out how good the night or site REALLY is.
- Compare the sky brightness at different sites quantitatively.
- Document the evolution of light pollution in your area.
- Set planetarium dome illumination to mimic the skies people are likely to experience elsewhere in the city.
- Monitor sky brightness through the night, night-to-night, and year-to-year.
- Determine which nights show the greatest promise for finding the 'faintest fuzzies'!
- Calibrate the effect of sky brightness on qualitative measures such as the Bortle Scale.
- Investigate how sky brightness correlates with the solar cycle and month-to-month sunspot activity.
- Help provide local ground truth for future sky brightness prediction with the Clear Sky Chart.
- CCD users can make a correlation between the SQM reading and when the background reaches some ADC level.
Features:
- Sky brightness reported in visual magnitudes per square arcsecond.
- Infrared blocking filter restricts measurement to visual bandpass.
- Sensor temperature, model number, and serial number are provided.
- Precision readings at even the darkest sites.
- Field-upgradeable firmware.
- Open protocol document.
Specifications:
- USB connectivity
- Included applications for reading data in Perl.
- The Half Width Half Maximum (HWHM) of the angular sensitivity is ~10°. The Full Width Half Maximum (FWHM) is then ~20°. The sensitivity to a point source ~19° off-axis is a factor of 10 lower than on-axis. A point source ~20° and ~40° off-axis would register 3.0 and 5.0 magnitudes fainter, respectively.
- Size 5.5 x 2.6 x 1.1 in.
- Maximum light sampling time: 80 seconds.
- Minimum light sampling time: 1 seconds.
- Specifications are subject to change without notice.
What you get:
- SQM-LU-DL unit
- USB flash drive containing the users manual, operation software (UDM), and example software. This can also be found online here.
- 15ft USB cable Battery-to-USB adapter with 6 AA cells and battery holder
- Calibration sheet indicates unit USB serial number, and calibration values
- Weatherproof housing
A USB enabled data-logging light meter for night-time sky brightness monitoring! An affordable meter for continual, connected or autonomous data-logging to measure sky brightness for astronomers and light pollution investigators. The "Sky Quality Meter" measures the brightness of the night sky in magnitudes per square arcsecond. Designed by Dr. Doug Welch and Anthony Tekatch
Uses:
- Measuring the night sky brightness during remote biological field experiments.
- Find out how good the night or site REALLY is.
- Compare the sky brightness at different sites quantitatively.
- Document the evolution of light pollution in your area.
- Set planetarium dome illumination to mimic the skies people are likely to experience elsewhere in the city.
- Monitor sky brightness through the night, night-to-night, and year-to-year.
- Determine which nights show the greatest promise for finding the 'faintest fuzzies'!
- Calibrate the effect of sky brightness on qualitative measures such as the Bortle Scale.
- Investigate how sky brightness correlates with the solar cycle and month-to-month sunspot activity.
- Help provide local ground truth for future sky brightness prediction with the Clear Sky Chart.
- CCD users can make a correlation between the SQM reading and when the background reaches some ADC level.
Features:
- Sky brightness reported in visual magnitudes per square arcsecond.
- Infrared blocking filter restricts measurement to visual bandpass.
- Sensor temperature, model number, and serial number are provided.
- Precision readings at even the darkest sites.
- Field-upgradeable firmware.
- Open protocol document.
Specifications:
- USB connectivity
- Included applications for reading data in Perl.
- The Half Width Half Maximum (HWHM) of the angular sensitivity is ~10°. The Full Width Half Maximum (FWHM) is then ~20°. The sensitivity to a point source ~19° off-axis is a factor of 10 lower than on-axis. A point source ~20° and ~40° off-axis would register 3.0 and 5.0 magnitudes fainter, respectively.
- Size 5.5 x 2.6 x 1.1 in.
- Maximum light sampling time: 80 seconds.
- Minimum light sampling time: 1 seconds.
- Specifications are subject to change without notice.
What you get:
- SQM-LU-DL unit
- USB flash drive containing the users manual, operation software (UDM), and example software. This can also be found online here.
- 15ft USB cable Battery-to-USB adapter with 6 AA cells and battery holder
- Calibration sheet indicates unit USB serial number, and calibration values
- Weatherproof housing
Useful Resources
- User Manual: SQM-LU-DL Instruction Sheet (PDF format)
- Frequently Asked Questions
- SQM Comparison Chart
Other Information
- Country of Manufacture: Canada

Unihedron Sky Quality Meter with Lens - Narrow Field of View / USB Data Logging & Housing
