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Unihedron

Unihedron Sky Quality Meter - LR (SQM-LR)

Unihedron Sky Quality Meter - LR (SQM-LR)

Regular price $144.47 USD
Regular price $212.46 USD Sale price $144.47 USD
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Unihedron Sky Quality Meter - LR

An RS232 SQM model for night-time sky brightness monitoring!

An affordable meter for continual, connected measuring of sky brightness for astronomers!

The "Sky Quality Meter - LR" measures the brightness of the night sky in magnitudes per square arcsecond.

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.

Deployment:

  • Legacy computer interface installations.
  • MODEM interface installations.
  • Simple electronic interface projects.

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.

Technical Specifications

  • RS232 connectivity
  • Included applications for reading data in Perl.
  • 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

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  • 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

  • SQM-LR unit
  • SQM-LR users manual
  • USB flash drive containing the users manual, operation software (UDM), and example software. This can also be found online.
  • 6ft RS232 straight through cable
  • International AC adapter
  • Calibration sheet indicates unit serial number, and calibration values

Warramty & Manual

Warranty : Unihedron warranty

Manual: Unihedron

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