Sky Quality Meter - SQM-LU-DL-V

Article number:	SQM-LU-DL-V
Availability:	More on the Way to us
Delivery time:	Special Order

Sky Quality Meter - LU-DL-V

"You've got to kick at the brightness 'til it bleeds starlight." - with apologies to Bruce Cockburn

A USB enabled vector data-logging light meter for night-time sky brightness monitoring! An affordable meter for continual, connected or autonomous data-logging to measure sky brightness for astronomers and light pollution investigators. The "Sky Quality Meter - LU-DL-V" (SQM-LU-DL-V) measures the brightness of the night sky in magnitudes per square arcsecond. Designed by Dr. Doug Welch and Anthony Tekatch

---

Uses: Measuring the night sky brightness during remote biological field experiments. 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.

SQM-LU-DL-V UDM contour plot

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.
• All the features of our SQM-LU (USB model) plus Data logging capabilities and vector measurements.
• Open protocol document.

 

Specifications:

• USB connectivity.
• Data-logging capabilities while operated from external battery.
• Vector measurements of Altitude and Azimuth (built-in accelerometer/compass module).
• 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. The "V" model comes with an improved lens/filter arrangement, see the comparison to the standard "L" model here.
• Size 5.5 x 2.6 x 1.1 in.
• Maximum light sampling time: 80 seconds.
• Minimum light sampling time: 1 seconds.
• Battery adaptor fashioned like a handle for easy use in field during all sky surveys. 3D part view.
  

Notes:

• The compass readings are very sensitive to any nearby hard and soft iron. The unit works well by hand operation as shown above.
• There is a slight magnetic offset (pinched and stretched at ≈±5° in some directions) due to internal components which have yet to be compensated for in the UDM software, but the compensation is planned for a future release of UDM.
• The lens/filter arrangement has been improved over our standard "L" models. A comparison with the new UVIR650 IR Filter and half-ball lens can be found here. spectral response.

Specifications are subject to change without notice.

---

What you get:

SQM-LU-DL-V unit USB flash drive containing the users manual, operation software (UDM), and example software. The can also be found online. 15ft USB cable Battery-to-USB adapter with 4 AA cells and battery holder. This specially sized "hand-held" battery holder will not fit inside the weatherproof housing. If you want to put this vector model meter inside the weatherproof housing, then you should also get the DL batter holder DL-Batt. Calibration sheet indicates unit USB serial number, and calibration values