SQMeter¶
ESP32 dark sky quality monitor - sky brightness, cloud, rain and wind, an observatory safety monitor for N.I.N.A., and alerts that wake you when it matters.
SQMeter is an open-source sky quality meter built on the ESP32. It measures light pollution in real time and gives you Bortle class, SQM magnitude, and naked-eye limiting magnitude — accessible from any browser on your local network.
Try the Live Demo View on GitHub
Features¶
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Sky Quality Measurements
SQM (mag/arcsec²), NELM, and Bortle Scale 1–9 calculated from raw lux.
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Web Interface
Real-time dashboard over WebSocket. No polling. No app required.
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Environmental Sensors
Temperature, humidity, and pressure via BME280.
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MQTT Publishing
Push readings to Home Assistant, Grafana, or any MQTT broker.
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OTA Updates
Flash new firmware from the browser, or let the device update itself directly from GitHub Releases.
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ASCOM Alpaca
Native SafetyMonitor + ObservingConditions device for N.I.N.A. — no separate bridge required. Tested with ASCOM ConformU on every change.
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Safety & alerts
Rain, wind, cloud, SQM, humidity and dew-point rules. Alerts via Pushover, ntfy, webhook, MQTT or a paired phone over Bluetooth — and switched off while you're not imaging.
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Rain & wind
Optional Hydreon RG-15 rain gauge and anemometer / wind vane.
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Sun & Moon
Twilight, darkness and moon chart for the night ahead from your location.
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Open Hardware
Standard I2C sensors. Runs on any ESP32 dev board.
Sensors¶
| Sensor | Measures | Interface |
|---|---|---|
| TSL2591 | Lux (full / visible / IR) | I2C 0x29 |
| BME280 | Temperature, humidity, pressure | I2C 0x76 |
| MLX90614 | IR cloud temperature | I2C 0x5A |
| GPS (optional) | Location & time | UART |
| RG-15 (optional) | Rain detection | UART |
Quick Start¶
New device? Go to Flashing Your Device — you only need a USB cable and the release binaries.
Already flashed? Go to First Boot to configure WiFi.