outdoor electronics

Sky Quality Meter - L [SQM-L]

Unihedron   ——   SKU: SQM-L
$149.00 CAD
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Product Info


About the Unihedron Sky Quality Meter - L...

Finally... an affordable meter for measuring sky brightness for astronomers!


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 SQM reading and when the background reaches some ADC level.



Unihedron Sky Quality Meter - L Features...


  • 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.



Unihedron Sky Quality Meter - L Specifications...

The Half Width Half Maximum (HWHM) of the angular sensitivity is ~10 degrees. The Full Width Half Maximum (FWHM) is then ~20 degrees. The sensitivity to a point source ~19 degrees off-axis is a factor of 10 lower than on-axis. A point source ~20 degrees and ~40 degrees 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 in.

Maximum light sampling time: 80 seconds.

Specifications are subject to change without notice.

Unihedron Product Number: SQM-L

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