Finally, an affordable meter for measuring sky brightness!
The Unihedron "Sky Quality Meter-L" measures the brightness of the night sky in magnitudes per square arcsecond.
Unprecedented sensitivity in a handheld meter!
Designed by Dr. Doug Welch and Anthony Tekatch
- 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 Clock.
- CCD users can make a correlation between the Unihedron SQM-L reading and when the background reaches some ADC level.
- Audible signal while measurement is in progress.
- Sky brightness displayed in visual magnitudes per square arcsecond.
- Infrared blocking filter restricts measurement to visual bandpass.
- Temperature in both Celsius and Fahrenheit as well as model number and serial number can be displayed with different button press sequence.
- Precision readings at even the darkest sites.
- Power-saving features designed in for maximum battery life.
- Reverse battery protection.
Specifications for the Sky Quality Meter-L...
- 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.
- Operates from 9V battery (included).
- Size: 3.6" x 2.6" x 1.1"
- Maximum light sampling time: 80 seconds
- Specifications are subject to change without notice.
- Additional Information
SKU UH-SQM-L Manufacturer Unihedron Warranty 1 Year Warranty
Customer Reviews 1 item(s)
- Terrific stand alone sky quality meter!
I presently own the original one, but seeing this one had the lens that enables a much more narrow portion of the sky to be gauged, I bought this one as well. During a recent vacation in west Texas, with a stopover in Fort Davis, Texas, home of the Texas Star Party, I brought both along. Finding an area in town in the shadows afforded me the ability to to run a comparison test. I measured with the old one, and obtained a reading of 20.43. With the lens unit, I was able to record a reading of 21.63, almost a full unit of measurement darker. I know there are apps to use on a smart phone, however after owning one of these for a number of years, I feel more confident that this gives much more accurate results. My intention is to use it at home here in NJ (very light polluted skies) each night during cloud-free, no moon nights and see how the sky changes from night to night, season to season. I would highly recommend this meter.
1= Houston, We Have a Problem & 5= It's Out of This World
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