Best Collimation Tools for Newtonian Telescopes
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If you own a refractor, stop reading: you need none of this. A refractor is a sealed tube with a lens at the front, collimated at the factory, and it stays that way for life. Everything below is for owners of Newtonian reflectors and Dobsonians, where two mirrors have to be aimed at one another and drift apart with handling.
Still here? Then the honest starting point is that a misaligned Newtonian produces soft, flared stars that look exactly like bad optics, and a great many “this telescope is rubbish” verdicts are really uncollimated telescopes. The fix takes five minutes once you have done it once. The hard part is the first time.
Which is why the order in which you buy the tools matters more than the tools. A Cheshire eyepiece comes first, not because it is more accurate than a laser but because it shows you what is misaligned and teaches you the geometry. A laser is faster, and becomes a real time-saver once you already know what you are looking at. Bought in the other order it mostly produces confident mistakes.
First purchase — SVBONY SV197 Cheshire: no batteries, nothing to calibrate, shows the whole alignment at once.
Same job, different badge — Celestron Cheshire collimation eyepiece.
Later, for speed — SVBONY SV121 laser collimator, adjustable so you can true it yourself.
Costs nothing — a collimation cap made from a plastic lid with a small central hole. It really does work for centring.
What the two tools actually do
| Cheshire | Laser | |
|---|---|---|
| Shows you | Both mirrors and their reflections, all at once | One dot |
| Needs | Daylight or a torch, nothing else | Batteries, and to be true itself |
| Speed | Slower, needs a second look | Fast, one person, in the dark |
| Failure mode | You misread it and try again | An untrue laser makes you misalign a correct telescope |
Two practical notes before the picks. Whatever you buy, it needs to be a snug fit in your focuser, because slop in the drawtube introduces more error than the misalignment you set out to correct. And with a laser, insist on one you can adjust: a sealed unit you cannot true yourself is a gamble you will re-run every time it takes a knock.
The tools, in the order you should buy them
SVBONY SV197 Cheshire
A 1.25-inch combination Cheshire and sight tube: fine crosshairs, and an angled, brightly finished face that bounces light down the tube. What you get through it is the secondary mirror, the primary’s reflection and the crosshairs all in one view, so you can see which element is off instead of guessing. That understanding, rather than the metal, is what you are paying for.
It needs light falling on the angled face, so this is a daylight or torch-lit job at the kitchen table rather than something you do mid-session. It also takes a little practice: the nest of reflections is baffling right up until it abruptly is not. It works best if your primary has a centre spot, which most do; marking one yourself is a separate job that involves reaching near the mirror, and while you are in there, resist the urge to clean it. Coatings are delicate, a film of dust costs almost nothing in contrast, and more mirrors are ruined by cleaning than by dirt.
Celestron Cheshire collimation eyepiece
The same job from an established optics brand, with the fit and finish that implies. Choose it if you prefer your accessories to come from the same maker as your telescope, or if the SVBONY is out of stock. There is also a short-body Astromania version for focusers with limited inward travel, which is worth knowing about if your drawtube runs out of room — measure that before you choose between them. Otherwise the caveats are the ones every Cheshire carries: light on the face, and a learning curve.
SVBONY SV121 laser collimator
An adjustable red laser with a 2-inch adapter, projecting a dot you align to the primary’s centre spot. Its case is speed: ninety seconds, one person, in the dark. That matters most if the telescope travels in a car boot and wants checking once you reach the site, and it is where a dim red torch pays for itself, since you will be reading knobs and thumbscrews rather than the sky.
Against it: a laser does not reveal secondary rotation and placement the way a Cheshire does, so treat it as a refinement tool rather than a complete one. It needs batteries. The rotation test above is not a one-off acceptance check — run it every time, because the truing drifts. And the obvious: never point it at a person, and never put your eye to the focuser while it is switched on.
Check the SV121 laser collimator
The free one, which is not a joke
A collimation cap is any cap that fits your focuser snugly with a small hole drilled dead centre — the classic is a 35 mm film canister lid. Looking through that hole puts your eye exactly on the optical axis, which is enough to check that the secondary is centred and to drag a badly misaligned telescope back to roughly right. It costs nothing and it is a sound way to find out whether you want a proper tool at all.
What it cannot do is fine-tune the primary, because there are no crosshairs and no illuminated face to judge against. That gap is precisely where the Cheshire earns its keep.
When you actually need to do it
- After any journey of consequence — a car boot over rough road, a flight, a house move.
- If stars look like commas or fans rather than round points at high power.
- Not every session. A tabletop Dobsonian carried gently into the garden may hold alignment for months.
- Longer tubes drift more than short ones, and truss or collapsible designs more than solid tubes.
The final arbiter costs nothing and outranks every tool on this page. Point at a moderately bright star at high power and defocus slightly: you should see concentric rings with the dark central shadow sitting in the middle. Off to one side means collimation needs attention; centred means your telescope is fine no matter what any device suggested. For that test you want real magnification, so a decent 9 mm eyepiece is the other thing worth having in the maintenance bag.
Quick answers
Do I need to collimate a new telescope?
Check it. Newtonians often shift a little in shipping. Refractors never need it.
Cheshire or laser for a beginner?
Cheshire, clearly. It teaches you what alignment looks like. Add a laser later if speed starts to matter.
Are cheap laser collimators accurate?
Some are and some are not, and the price does not tell you which. Run the rotation test: if the dot circles as you turn the laser in the focuser, it is lying to you.
How often should I collimate?
Whenever the telescope has been moved a meaningful distance, and whenever the star test says so. Not on a schedule.
Can I collimate with no tool at all?
Roughly, yes — a home-made cap plus the defocused star test will pull a badly misaligned scope back into usable shape.
What to read next
- Best Dobsonian Telescope — the telescopes this page applies to.
- Accessories & Maintenance.
- Best Eyepieces for Beginners — including what you need for the star test.
- Best Telescope Accessories to Buy First.
How we reviewed this (updated 16 October 2026): this page is based on manufacturer specifications, listing details and public buyer feedback. We have not hands-on tested the products listed.
Affiliate disclosure: AstroGear Lab is a participant in the Amazon Services LLC Associates Program. If you buy through a link on this page we may earn a small commission at no extra cost to you. As an Amazon Associate I earn from qualifying purchases. Product mentions are editorial choices, not paid placements. We do not quote prices or star ratings because both change daily — check the current listing. Read our full affiliate disclosure.
