Finally, an affordable meter for measuring sky brightness for astronomers!  The "Sky Quality Meter" 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.

Uses:

• 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.

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.

Specifications:

• Operates from 9V battery (included).
• Size 3.8 x 2.4 x 1 in.
• Maximum light sampling time: 8 0 seconds.
• Specifications are subject to change without notice.