ASCOM Alpaca Simulators

A comprehensive simulator for ASCOM Alpaca devices that provides a RESTful API for testing and developing observatory control software.

Features

• Complete Device Simulation: Supports all major ASCOM device types including:

  • Camera
  • Telescope
  • Dome
  • Focuser
  • Filter Wheel
  • Rotator
  • Safety Monitor
  • Switch
  • Observing Conditions
  • Cover Calibrator

• Realistic Image Generation: Uses cabaret to generate authentic astronomical images for camera simulation

• RESTful API: Fully compliant with the ASCOM Alpaca Device API specification

• Interactive Test Interface: Web-based control panel for manual testing

• Configurable Devices: YAML-based configuration for all device properties

Quick Start

The fastest way to run the simulator is using uv.

1. Clone the repository:

   git clone https://github.com/ppp-one/alpaca-simulators
   cd alpaca-simulators

2. Run the simulator:

   uv run alpaca-simulators

   This will automatically install dependencies and start the server at http://0.0.0.0:11111.

Configuration & Options

The simulator supports several command-line arguments:

# Run on a different port with auto-reload enabled
uv run alpaca-simulators --port 8080 --reload

# Use a specific configuration file
uv run alpaca-simulators --config my_custom_setup.yaml

Test Interface

The simulator includes a web-based test UI at http://localhost:11111/test_interface that allows you to:

• GET properties: Retrieve current values from any device property
• PUT operations: Set values and trigger actions using form inputs

Device Configuration

On first run, the simulator generates src/alpaca_simulators/config/config.yaml from a template. You can modify this file to set:

• Device names and descriptions
• Initial property values
• Capabilities and limits
• Available options (e.g., filter names, camera properties)

Example API Calls

# Get telescope position
curl http://localhost:11111/api/v1/telescope/0/rightascension

# Set camera exposure time
curl -X PUT http://localhost:11111/api/v1/camera/0/startexposure \
  -d "Duration=5.0&Light=true"

# Check if dome is at home
curl http://localhost:11111/api/v1/dome/0/athome