70–90 mm refractor on an alt-az mount
Sky-Watcher Evostar 90/900 AZ-3
The shape most people picture when they picture a telescope. Sealed tube, nothing to collimate, and a standing eyepiece height that suits sharing.
€258seen 23 Oct 2026 at Astroshop
Price alert
One email when the price we observe for the Sky-Watcher Evostar 90/900 AZ-3 falls at least 5% below the lowest we observed in the previous 30 days. At most one a week.
- 90 mmAperture
- f/10.0Focal ratio
- 11.7 kgTypical weight
- 15–180×Useful magnification
Should you buy it?
- Yes if what you mainly want is sharing it with children: that is what this family does best.
- No if your priority is nebulae, clusters and galaxies, by eye: other families do better for the same money.
Computed from its family's per-goal scores and its own numbers — not a rating, not one evening's opinion.
Where to buy
Also search at First Light Optics · Optique Unterlinden · Pierro Astro · Teleskop-Express (searches; neither price nor stock checked)
1 of these 5 links earn us a commission, marked above. Sorted by price, never by what pays. How this site is funded.
Prices are observed on the date shown, never live. Links marked paid link earn us a commission and cost you nothing extra.
Observed price history
Unchanged at Astroshop: €258 at each of the 25 readings from 29 Sept 2026 to 23 Oct 2026.
Only prices actually read on the retailer’s page, one per day at most; a day without a reading is a gap, not a guess.
What it shows, really
These circles are simulations, computed from the aperture, the magnification and the sky — indicative, not exact. A real night also depends on the turbulence, your eyes and your experience. Closer to the truth than the photo on the box; still not a promise.
Under a suburban sky (Bortle 6), through a common 25 mm eyepiece for wide targets and a 10 mm for planets. Every circle is the true field — nothing is enlarged.
Photo credits
These thumbnails are built from real photographs, scaled and darkened by the same arithmetic as the large view.
The numbers
Photo: Astroshop| Aperture | 90 mm |
|---|---|
| Focal ratio | 900 mm · f/10.0 |
| Mount | AZ-3 alt-az with slow-motion controls on both axes, aluminium tripod |
| Typical weight | 11.7 kg |
| Eyepieces | 25 mm and 10 mm |
| Useful magnification | 15× to 180× at 90 mm |
| Resolution (Dawes) | 1.3″ — the tightest double star this aperture can split |
| Faintest star, suburban sky | around magnitude 11.0 |
| Observed price | €258 seen 23 Oct 2026 at Astroshop |
Made for
- Sharing it with children
Standing height, sealed tube, and no mirror to knock out of line.
- The Sun
In white light: sunspots with their penumbra, faculae near the edge, and granulation on a steady morning. Dawes' limit on the Sun: 1.3″ (116 ÷ 90 mm, arithmetic). It needs a certified cell over the front whose range holds its 115 mm outside diameter: the Omegon Helievo 112 (104–128 mm), €69 (seen 26 Sept 2026). Every time: certified filter over the front · finder capped · never an eyepiece filter · an adult with children · never without the filter · measure first.
Not made for
- Nebulae, clusters and galaxies, by eye
Bright clusters and the Orion Nebula. Galaxies are mostly out of reach.
The Sun, safely
No solar filter in the box
The Sun with this model
It needs a certified cell over the front whose range holds its 115 mm outside diameter: the Omegon Helievo 112 (104–128 mm), €69 (seen 26 Sept 2026).
In white light: sunspots with their penumbra, faculae near the edge, and granulation on a steady morning. Dawes' limit on the Sun: 1.3″ (116 ÷ 90 mm, arithmetic).
The listing gives a fit of 104–128 mm across the outside of the tube. Clear aperture 112 mm. The listing names no standard; no international standard exists for filters on telescopes, binoculars or lenses (AAS).
Where to buy
1 of these 1 links earn us a commission, marked above. Sorted by price, never by what pays. How this site is funded.
Every time
- A certified solar filter over the FRONT of the instrument, fastened so it cannot slip or blow off.
- Cap or remove the finder. It is a second telescope, and it has no filter.
- Never a filter at the eyepiece end: the concentrated sunlight there can crack it in an instant.
- With children, an adult is there every time.
- Never look, or point, without the filter on. Check it before each use; a scratched or torn filter goes in the bin.
- Measure before ordering. A cell that sits loose can fall off.
Sources for the Sun
- American Astronomical Society — How to View a Solar Eclipse Safely — filters on optics go on the front; eclipse glasses never with optics; children supervised
- American Astronomical Society — Solar Filters for Optics — eyepiece filters are dangerous; the finder capped, removed or filtered; the filter attached securely
- American Astronomical Society — About the ISO 12312-2 Standard — EN ISO 12312-2:2015 covers naked-eye viewers only; no international standard covers filters on telescopes, binoculars or lenses
- Société astronomique de France — Guide des observations solaires — a filter at the front, never one screwed into the eyepiece, the finder capped
- NASA — Keep Your Eclipse Glasses to See the Sun's ‘Freckles’ — a large enough sunspot shows through eclipse glasses
- AAVSO — Le Guide d'Observation Solaire de l'AAVSO, v1.1 (2017), p. 6 — archived copy — “Les ouvertures plus grandes que 100 à 125 mm sont généralement limitées par les effets de turbulence atmosphérique”; 50 to 80 mm is enough to count sunspots
The family it belongs to: 70–90 mm refractor on an alt-az mount
What it does well
- Point it and look. No collimation, ever
- The eyepiece stays at a comfortable height wherever you aim
- Doubles as a daytime spotting scope
What it costs you
- 70–90 mm is not much light. Deep sky is a short list
- Cheap achromats show a violet fringe on the Moon and bright planets
- The bundled tripod is usually the weak part — a wobbly tripod ruins a good tube
Worth knowing about this model
The long achromat the French forums name when a refractor is the right answer: f/10 keeps the colour fringing small, the AZ-3 has real slow-motion knobs, and nothing needs adjusting, ever. A 90 cm tube on a tripod — fine on a balcony where a Dobsonian will not fit. Less light than a 130 mm tabletop at a similar price; that is the trade, not a flaw.
Same family, other sizes
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Read next
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- Aligning the finder, in daylightThe commonest cause of a failed first night, fixed in ten minutes, in daylight, on a distant pole.Updated 8 Oct 2026
€258seen 23 Oct 2026 at Astroshop
Where to buy