The Polaris Handbook

Browser-controlled astrophotography with Polaris Astro Controller

Preface

Polaris Astro Controller grew fast. What started as a lightweight, browser-controlled fork (an independent offshoot that shares its starting code) of N.I.N.A., the popular Windows desktop imaging program, built for the Raspberry Pi, is now a complete astrophotography system: equipment control, guiding, focusing, planning, live stacking, planetary capture, and a full post-processing suite with AI tools that run right in the browser. The documentation grew with it, one page at a time, and today it spans more than fifty files across the repository. Every feature is documented somewhere; the problem is knowing where.

This book is the answer. It is the single, organized reference for everything Polaris: how to use it, how it behaves, and how it works inside. It replaces no code and invents no features; it consolidates what the scattered documentation already knows into one coherent narrative, ordered the way you actually encounter the software, from the first install to the internals of the server.

Who this book is for

You have shot astrophotography before, or you are willing to learn the craft alongside the tool. Concepts like plate solving, dithering, and calibration frames get a one-line explanation in context and a proper entry in the glossary (Appendix B — Glossary), but this is a book about Polaris, not a general astrophotography course.

Two audiences share these pages:

• Users read Parts I through VI: installation, equipment, capture, processing, remote access, and the optional assistant. Everything is task-oriented and follows the arc of a real imaging session.
• Developers and integrators add Part VII: the server architecture, the REST and WebSocket APIs (the interfaces other programs use to command and monitor Polaris), configuration, and the development workflow.

How the book is organized

• Part I, Getting Started: what Polaris is, installing it on a Raspberry Pi, mini-PC, or Windows box, a tour of the interface, and your first night out.
• Part II, Equipment: rigs, drivers of every kind your gear might speak (INDI, Alpaca, ASCOM, native SDKs; each is explained there), DSLR and mirrorless cameras, mounts, and the built-in simulator.
• Part III, Capturing the Night: polar alignment, planning, focusing, guiding, sequencing (simple, advanced, and multi-target), live stacking, and planetary work.
• Part IV, Processing Your Images: from raw frames to a finished JPEG, entirely inside Polaris: STUDIO, channel combination, color calibration, AI cleanup, star removal, and the EDITOR.
• Part V, Remote Access and Administration: networking, HTTPS, the relay, authentication, and keeping a headless box (one that runs with no monitor or keyboard attached) healthy.
• Part VI, The Optional Assistant: Canopus Assistant, the opt-in AI companion, its paid cloud tier (whose subscription funds Polaris) and its two free, fully local backends, what it does, how to choose and enable a backend, and how it handles your telescope and your data.
• Part VII, Under the Hood: architecture, API, configuration, and how to build and contribute.
• Appendices: the requirements matrix, glossary, troubleshooting, and FAQ.

Conventions

• UI elements appear in bold: press Connect All in the RIGS tab.
• Sidebar tabs are written in capitals, as in the UI: RIGS, FOCUS, STUDIO.
• File paths, commands, and configuration keys use monospace.
• The machine running the Polaris server is called the host; the laptop, tablet, or phone showing the UI is called the client.

A note on this edition

This book tracks a moving target. It lives in the Polaris repository under book/ and is built with Quarto (a publishing tool that turns plain text into books and websites), so it evolves with the software it describes. Where the software and the book disagree, the software is right and a fix to the book is welcome.

The cover photograph, the Horsehead and Flame Nebulae in Orion, was captured and processed by the author.