Lanternfish – Sky Brightness Monitor

Lanternfish – Sky Brightness Monitor

Lanternfish is a sky brightness monitor designed to measure sky brightness in MPSAS (Magnitudes per square arcsecond), log data autonomously, and provide easy access from any device via Wi-Fi. Unlike traditional sky quality meters that require choosing between different models and features, Lanternfish integrates all key functions into a single device. 

No versions. No add-ons. No compromises.

Features:

• Compact flashlight-style design for quick and direct sky measurements
• Measurement of sky brightness in MPSAS (Magnitudes per square arcsecond) — the standard for sky quality
• FoV 18º - Calibrated sensor with defined angular coverage
• Automatic data logging with date and time
• Wi-Fi access via integrated web server
• Data export in CSV format
• Adjustable measurement modes to suit different uses
• Programmable automatic shutdown
• OLED display for direct visualization
• Rechargeable battery with autonomy lasting several nights (depending on the selected mode)

How to use

Point Lanternfish at the sky and take a reading either instantly or using a programmed mode.

The device automatically records data and allows access via its integrated web interface over Wi-Fi. Data can also be exported in CSV format.

Readings graph
Your whole night, at a glance
Lanternfish plots MPSAS and temperature for the whole night on a single graph — with the Lanternfish artwork in the background. Export as PNG directly from the interface.

White line: MPSAS — sky brightness - Higher values = darker sky. A reading above 21 MPSAS indicates an excellent, Bortle 1–2 class site.
Orange line: Temperature - Recorded simultaneously with each sky measurement. Shown on the right-hand axis, useful for correlating sky conditions with local temperature changes.

Operating modes
From a quick read to a full night of data
Use Lanternfish for a single instant measurement or run it autonomously all night — with configurable stop triggers so it powers down when you want it to.

Web interface
Access and control from any device
The Lanternfish web interface runs directly on the device — open it in any browser. No app to install, no account to create, no cloud dependency.

Night mode overview — readings graph with the full night plotted, history of previous sessions, and the live Control Panel showing the last MPSAS reading and battery level.

Readings History and live Control Panel — night-by-night summary with Max / Min / Avg MPSAS and temperature. The control panel shows the current reading and battery level at a glance.

Settings panel — Wi-Fi network configuration, temperature unit, firmware version and OTA update. Device information including IP address, serial number and internal time.