How to Collimate Your Telescope
A complete, step-by-step walkthrough for aligning your Newtonian or Dobsonian reflector — in three layers, from preparation to a precision autocollimator finish.
Every Newtonian needs collimation. They ship imperfectly aligned and slowly drift out of alignment — or “decollimate” — as you move them. A truss-tube Dob needs a tune-up every time you set it back up; a solid-tube scope needs periodic checks. The good news: with the right tools and this guide, it takes only a few minutes, and the jump in image sharpness is immediate.
This guide is organized as three layers. Most observers live in Layers 1–2; Layer 3 is the precision finish for fast imaging scopes and anyone chasing the tightest stars.
Layer 1 — Preparation
Center-spot the primary, make the mirror cell hold its adjustment, and position & rotate the secondary. Do this before you collimate.
Start Layer 1 →Layer 2 — Two-Tool Collimation (Laser & Cheshire)
The everyday collimation. The laser sets the focuser axis and ballparks the primary; the Cheshire sets the primary precisely.
Start Layer 2 →Layer 3 — Autocollimator
The precision finish. Refine and verify with the single-pupil autocollimator (iterative and CDP methods), with an interactive eyepiece-view tool.
Start Layer 3 →Download the Guides
Prefer to read at the eyepiece or print for the field? Grab the PDF guides — a Quick-Start for just the steps, or the Complete Manual with full theory and diagrams.
The Tools You'll Use
This guide is written around the Farpoint two-tool workflow. Each tool handles a different part of the alignment:
These procedures are for Newtonian and Dobsonian reflecting telescopes. CATSEYE™ is a trademark of CatEye Collimation; Farpoint is not affiliated with CatEye Collimation.