RASC Victoria Centre AGM Speaker: The Life and Times of the Sky Quality Meter (SQM) – Doug Welch, Unihedron
- 2005 first SQM manufactured
- Anthony Tekatch
- co-inventor of SQM
- PCB design, app coder (Unihedron Device Manager), production of all meters, user support
- IR limiting filter in front of sensor
- SQM-L – handheld +- 20º viewing angle
- SQM-LU – USB connected device, continuous monitor, light pollution surveys with GPS
- SQM-L-DL – data logger, runs for about a month on AA batteries
- SQM-LE – PoE Ethernet device, can function as a cloud monitor
- Website illustrates the cloud sensing function
- 10,000 SQM devices being used
- Used for mapping night sky quality worldwide, with lots of published studies
- Sea turtle light trespass use case
- Car-based mobile light pollution surveys – using a SQM-LU & computer
- Q&A
- Victoria Centre teams mapped light pollution in our area back in 2010 – Sid Sidhu & David Lee
- Can interface to Raspberry Pi with Python code
- Is it weather proof? No, but a weather enclosure is available which copes with most conditions
- Are the various models interoperable? Yes, all SQMs are calibrated before shipping.
- Milky Way can affect readings by 0.2 in southern hemisphere, 0.1 in the northern hemisphere
- Driving technique – stop then take reading is recommended
- Magnitudes/square second? It’s a logarithmic surface brightness number. Darkest are 22, meter saturates at 6 (not daytime).
- Has the SQM been useful in reducing light pollution? Yes, promoting dark areas and encouraging change.
- Discussion about measuring darkness from a very dark site and the contribution of the Milky Way in that case