Unihedron Sky Quality Meter - LE

Unihedron Sky Quality Meter - LE

An ethernet-enabled SQM model for night-time sky brightness monitoring! An affordable meter for continual, connected measuring of sky brightness for astronomers! The "Sky Quality Meter - LE" measures the brightness of the night sky in magnitudes per square arcsecond. Designed by Dr. Doug Welch and Anthony Tekatch

Live SQM-LE results from the Unihedron office

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:

• Sky brightness reported in visual magnitudes per square arcsecond.
• Infrared blocking filter restricts measurement to visual bandpass.
• Sensor temperature, model number, and serial number are provided.
• Precision readings at even the darkest sites.
• Field-upgradeable firmware
• Open protocol document

Weatherproof Housing

This housing design is made to protect the SQM-LE/LU from normal outdoor conditions including weather and insects.

Features:

• White surfaces reflect the hot summer sunshine.
• Opening on bottom to allow moisture to escape.
• Glass top to prevent scratching when removing ice.
• Raised glass surface to prevent dirt and leaves from collecting.
• Small glass opening to minimize internal heating due to the Sun.
• Cable opening at bottom sealed with open-cell (breathable) foam prevents insects from entering.
• Marine silicone seal rated for outdoor use.
• Silicone seal around glass extends beyond glass-plastic interface to prevent ice from building in crevices.
• Hose clamps for easy mounting to pole.
• Staples for easy mounting to wood surface.

Details:

• Diagram of all SQM meters that fit into housing (PDF)
• Photos
• Glass versions (PDF)
• SQM-LE wiring layout inside housing.

What you get:

• Housing with removable top cap. 8.8 x 18.7cm, 360g.
• Two adjustable clamps.
• Two staples for mounting to wood.
• Instruction sheet.
• An optional PoE (Linksys WAPPOE-5V or D-Link DWL-P200 or TL-POE200) for extended length SQM-LE installations.

Technical Specifications

• Ethernet connectivity
• Included applications for reading data in Java, C, Perl, Python.
• 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.
  Comparison chart.
• Operates from 5-6VDC adapter (included).
• Size 3.6 x 2.6 x 1.1 in.
• Maximum light sampling time: 80 seconds.
• Minimum light sampling time: 1 seconds.
• Specifications are subject to change without notice.

In the Box

Meter only:

• SQM-LE unit
• International Power adapter
• USB flash drive containing the users manual, operation software (UDM), and example software. This can also be found online.
• 6ft Ethernet cable (straight through for connection to hub/router)
• Ethernet crossover cable or adapter (for connection directly to PC)
• Calibration sheet indicates unit MAC address, and calibration values

What you get (with housing):

• SQM-LE unit
• International Power adapter
• USB flash drive containing the users manual, operation software (UDM), and example software. This can also be found online.
• 6ft Ethernet cable (straight through for connection to hub/router)
• Ethernet crossover cable or adapter (for connection directly to PC)
• Calibration sheet indicates unit MAC address, and calibration values
• Weatherproof housing

What you get (with housing and PoE adapters): 

• SQM-LE unit
• International Power adapter
• USB flash drive containing the users manual, operation software (UDM), and example software. This can also be found online.
• 6ft Ethernet cable (straight through for connection to hub/router)
• Ethernet crossover cable or adapter (for connection directly to PC)
• Calibration sheet indicates unit MAC address, and calibration values
• Weatherproof housing
• Power over Ethernet kit with North American plug (may look different than photo)

Warranty & Manual

Warranty: Unihedron Warranty