AMSKY02 – Sky Quality and Cloud Sensor

The AMSKY02 is a compact, weatherproof sky sensor designed for astronomical and environmental applications. It combines multiple sensors in one unit:

• Dual sky brightness sensors (SQM) – 10° and 60° field of view, measuring sky brightness in mag/arcsec².
• 32×24 pixel infrared cloud sensor – dual thermopile array for detailed sky temperature mapping (64×48 variant available).
• Water-pooling resistant design – sensor head geometry prevents water accumulation on optical surfaces.
• Temperature and humidity sensor – SHT41, monitors ambient air conditions.
• USB-C and RS-485 interfaces – for easy connection to PCs or automation systems.

Note: AMSKY02 is the successor to the original AMSKY01. Key improvements include dual SQM sensors (instead of a single one), a pair of IR thermopile arrays with redesigned mounting that doubles the resolution and field of view compared to AMSKY01, and an improved water-pooling resistant enclosure. Both models share the same software, protocol, and interfaces — the amsky01 Python package and INDI driver work with both.

Live Cloud Detection Example

The following video demonstrates real-time data from the AMSKY sensor as clouds pass through its field of view. The dual thermopile array with 32×24 pixel combined resolution provides detailed sky temperature mapping with 150°×110° field of view, allowing precise tracking of cloud coverage and movement patterns.

How the Pixel Sensor Works

The infrared cloud sensor is based on a dual thermopile array with 32×24 pixel combined resolution (64×48 variant available), acting like a low-resolution thermal camera for the sky.

Comparison of an optical image of the night sky with clouds from the AMASC01 allsky camera and the AMSKY thermopile pixel sensor.

Benefits of a pixel sensor:

• Spatial cloud detection: See not only if clouds are present, but exactly where and how many.
• Accurate sky background: By averaging only the coldest pixels, the device can minimize the influence of warm objects (trees, chimneys, buildings) at the edge of the field of view.
• Robust automation: Algorithms can ignore local obstructions and focus on clear-sky regions, improving reliability for observatory control.
• Real-time visualization: Instantly visualize cloud structure and movement on the included GUI or in your own analysis scripts.

Key Features

• Real-time sky quality measurements (SQM) to assess light pollution.
• Fast and reliable cloud detection using infrared sky temperature.
• Accurate ambient temperature and humidity monitoring.
• USB-C (CDC Serial) interface for plug-and-play operation with computers.
• RS-485 interface for integration with observatory or building automation.
• Open protocol and API documentation for custom applications.
• Designed for continuous outdoor use in observatory conditions.

Applications

• Light pollution monitoring.
• Automatic observatory control (e.g., dome closure during clouds).
• Weather condition logging for astronomical sites.
• Networked sky sensor systems and citizen science projects.
• Environmental data collection and automation.

Technical Specifications

Parameter	AMSKY01	AMSKY02
Cloud detection	Thermopile array 16×12 px 75°×110° FoV	Dual thermopile array 32×24 px 150°×110° FoV High-res variant: 64×48 px available
Sky brightness (SQM)	Single sensor (10° or 60° FoV, selectable)	Dual sensor: 10° and 60° FoV mag/arcsec²
Temperature	−15 °C to +50 °C	−30 °C to +70 °C
Humidity	Relative humidity sensor
Interfaces	USB-C (CDC serial), RS-485
Power supply	USB bus power or external 8–13 V DC
Ingress protection	IP53W

Interfaces

USB-C (CDC Serial)

• Virtual serial port communication.
• Outputs real-time sensor data in ASCII or structured format.

RS-485

• Industrial interface for robust long-distance communication.
• Suitable for integration into SCADA or observatory control systems.

Communication Protocol

• Open protocol with documented commands and responses.
• Available API and example code for integration.