Handheld SQM unit

An affordable meter for measuring sky brightness for astronomers!

The "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

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:

• 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. Annotated FOV spec.
• Operates from 9V battery (included with courier shipments).
• Size 3.6 x 2.6 x 1.1 in. (92 x 67 x 28mm)
• Weight 0.31 lb (0.14 kg)
• Maximum light sampling time: 80 seconds.
• Specifications are subject to change without notice.