A small tube whose only job is to watch one star · review
A 70/400 guide scope with a helical focuser offering 90 mm of range including 10 mm of micro-focus, supplied with tube rings, a Synta plate and an adjustable counterweight.
The bottom line The largest and most capable guide scope of the three here, and the one with the most to carry.
f/5.7, which is a longer focal ratio than a small guide scope and twice the focal length. For a main telescope of significant focal length that matters: a guide star’s movement has to be resolvable before it can be corrected.
Ninety millimetres of range with ten of micro-focus, a brass compression ring, two thumbscrews and a lockable draw tube. That range means back-focus problems mostly disappear, and the compression ring keeps the camera centred and unmarked.
Tube rings sized for the scope, a Synta-style plate and an adjustable counterweight to balance the whole assembly. Everything needed to put it on a main telescope is in the box.
The translation renders the counterweight as “Dovanygewicht” and the focuser as a “Wurmauszug”. Neither is a real term; both are clear enough in context, and they are noted here because the specification figures around them are the ones worth trusting.
German, French, Italian and Spanish Amazon stores ran from 189 € to 201 € on the day of the survey.
American and British Amazon stores list it in local currency, which the euro range above sets aside.
Figures as Keepa reported them on the day this page was last updated. Stock and pricing shift without warning.
Prices quoted in this text were read on 17 September 2026. The live price is at the top of the page.
| Aperture | 70 mm (from the title) |
|---|---|
| Focal length | 400 mm, as the maker publishes it |
| Mounting method | Matching tube rings, Synta mounting plate, adjustable counterweight |
| Flexure resistance | Black anodised aluminium with milled knurled rings |
| Focuser type | Helical with a brass compression ring and two thumbscrews |
| Back focus | 90 mm total, of which 10 mm is micro-focus, as the maker states it |
| Weight | Not published by the maker. |
| Amazon reference | B0799FK1RX (same reference on 6 Amazon marketplaces) |
| EAN | 6971336223347 |
For a long main telescope, generally yes: the guide scope has to see a star’s movement finely enough to correct the main one, and focal length is what provides that. The cost is weight and a larger flexure lever.
Different cameras place their sensors at different distances behind the fitting. A generous range means almost any of them can be brought to focus without extension tubes, which removes another joint from the chain.
50 mm aperture · 200 mm focal length · helical focuser
A 50/200 guide scope with a brass compression-ring helical focuser, 40 mm of travel including 10 mm of fine focus, supplied with tube rings and a Synta-style dovetail plate.
Best for: Guiding a main telescope of moderate focal length, and doubling as a wide finder
≈ $78 / £88 / €107
60 mm aperture · helical focuser · male T-thread
A 60 mm guide scope with a non-rotating helical focuser and a male T-thread at the eyepiece collar for screwing a guide camera on directly.
Best for: A guide scope that will spend half its life as a finder
≈ $82 / £94 / €100
114 mm mirror · 900 mm focal length · alt-azimuth mount
A 114/900 Newtonian on a simple alt-azimuth mount, supplied with three eyepieces, a 6x30 finder and a 1.5x erecting lens, recommended by the maker from age eight.
Best for: A family telescope where nobody wants to learn polar alignment
≈ £150 / €142
