Unihedron Sky Quality Meter with Lens - Narrow Field of View SQM-L
An affordable meter for measuring sky brightness for astronomers! The "Sky Quality Meter" measures the brightness of the night sky in magnitudes per square arc second and offers unprecedented sensitivity in a handheld meter. 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. - 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. (See photo 2) - Operates from 9V battery (included). - Size 3.6 x 2.6 x 1.1 in. - Maximum light sampling time: 80 seconds.