Unihedron Sky Quality Meter with Lens - Narrow Field of View / USB Data Logging: Enviro Kit with Solar Charger & Housing

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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.
This upgraded version of the SQM-LU-DL comes with the SQM-H Housing as well as a Solar Charging Kit.
About the Unihedron Solar Charger:
- This unit mounts to the sunny side of the SQM-H housing and charges up the 4xAA NiMH batteries (included) so that the SQM-LU-DL can operate throughout the nighttime.
- It replaces the original SQM-LU-DL battery pack.
- The clear plastic bottle keeps rain and snow from the inside.
- The smooth round shape reduces the possibility that a passing creature or person will catch on it.
- A drainage hole in the bottom allows accumulated moisture to escape.
- An open-cell foam insert prevents insects from crawling up inside the container.
- Even cloudy days provide sufficient charging to keep the batteries topped up.
- At one reading every five minutes, the SQM-LU-DL can hold almost a year's worth of readings without changing batteries.
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
- Clear plastic bottle to protect the charging circuit from the elements
- Solar panel with battery charging circuit with attached 32" (81cm) USB cable to connect to SQM-LU-DL
- 4-AA NiMH batteries (manufacturer may vary)
- Stainless steel clamp to mount to the included SQM-H housing
- Installation instructions (PDF)
- Calibration sheet indicates unit USB serial number and calibration values
- Weatherproof housing USB 2.0 A to B cable, 1ft length, data cable for programming and data retrieval
- No SQM-LU-DL users manual - you can get the manual online here
- No CD - you can get all required software from here
- No extra battery pack or batteries as the solar charger includes batteries
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.
This upgraded version of the SQM-LU-DL comes with the SQM-H Housing as well as a Solar Charging Kit.
About the Unihedron Solar Charger:
- This unit mounts to the sunny side of the SQM-H housing and charges up the 4xAA NiMH batteries (included) so that the SQM-LU-DL can operate throughout the nighttime.
- It replaces the original SQM-LU-DL battery pack.
- The clear plastic bottle keeps rain and snow from the inside.
- The smooth round shape reduces the possibility that a passing creature or person will catch on it.
- A drainage hole in the bottom allows accumulated moisture to escape.
- An open-cell foam insert prevents insects from crawling up inside the container.
- Even cloudy days provide sufficient charging to keep the batteries topped up.
- At one reading every five minutes, the SQM-LU-DL can hold almost a year's worth of readings without changing batteries.
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
- Clear plastic bottle to protect the charging circuit from the elements
- Solar panel with battery charging circuit with attached 32" (81cm) USB cable to connect to SQM-LU-DL
- 4-AA NiMH batteries (manufacturer may vary)
- Stainless steel clamp to mount to the included SQM-H housing
- Installation instructions (PDF)
- Calibration sheet indicates unit USB serial number and calibration values
- Weatherproof housing USB 2.0 A to B cable, 1ft length, data cable for programming and data retrieval
- No SQM-LU-DL users manual - you can get the manual online here
- No CD - you can get all required software from here
- No extra battery pack or batteries as the solar charger includes batteries
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.
This upgraded version of the SQM-LU-DL comes with the SQM-H Housing as well as a Solar Charging Kit.
About the Unihedron Solar Charger:
- This unit mounts to the sunny side of the SQM-H housing and charges up the 4xAA NiMH batteries (included) so that the SQM-LU-DL can operate throughout the nighttime.
- It replaces the original SQM-LU-DL battery pack.
- The clear plastic bottle keeps rain and snow from the inside.
- The smooth round shape reduces the possibility that a passing creature or person will catch on it.
- A drainage hole in the bottom allows accumulated moisture to escape.
- An open-cell foam insert prevents insects from crawling up inside the container.
- Even cloudy days provide sufficient charging to keep the batteries topped up.
- At one reading every five minutes, the SQM-LU-DL can hold almost a year's worth of readings without changing batteries.
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
- Clear plastic bottle to protect the charging circuit from the elements
- Solar panel with battery charging circuit with attached 32" (81cm) USB cable to connect to SQM-LU-DL
- 4-AA NiMH batteries (manufacturer may vary)
- Stainless steel clamp to mount to the included SQM-H housing
- Installation instructions (PDF)
- Calibration sheet indicates unit USB serial number and calibration values
- Weatherproof housing USB 2.0 A to B cable, 1ft length, data cable for programming and data retrieval
- No SQM-LU-DL users manual - you can get the manual online here
- No CD - you can get all required software from here
- No extra battery pack or batteries as the solar charger includes batteries
Useful Resources
- User Manual: SQM-LU-DL Instruction Sheet (PDF format)
- Frequently Asked Questions
- SQM Comparison Chart
Other Information
- Country of Manufacture: Canada
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Unihedron Sky Quality Meter with Lens - Narrow Field of View / USB Data Logging: Enviro Kit with Solar Charger & Housing


















