70–90 mm refractor on a manual equatorial mount
Sky-Watcher Evostar 90/900 EQ3-2
A long achromatic refractor on a small equatorial mount with a counterweight. The tube is the one also sold on an alt-az tripod; the mount follows the sky with one knob once it points at the celestial pole, and it is harder to learn and slower to set up than the tube needs.
€479seen 7 Oct 2026 at Astroshop
- 90 mmAperture
- f/10.0Focal ratio
- 15–180×Useful magnification
Should you buy it?
- No if your priority is nebulae, clusters and galaxies, by eye, learn my way around the sky, sharing it with children, taking it with me, first astrophotography, serious deep-sky imaging: 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.
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 | EQ3-2 manual equatorial on an aluminium tripod |
| 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 | €479 seen 7 Oct 2026 at Astroshop |
Made for
- 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: 90 mm gathers about half the light of a 130 mm, arithmetic.
- Learn my way around the sky
It teaches the celestial coordinates, a real skill, but star-hopping from a chart is slower than on a mount that moves up-down and left-right.
- Sharing it with children
An adult aligns it and points it. As a long tube swings round the pole the eyepiece climbs and drops, and the counterweight bar sits at a child's head height (experience).
- Taking it with me
A 90 cm tube, a tripod and a head with its counterweight: a car, not a plane.
- First astrophotography
A phone at the eyepiece on the Moon. Not long exposures: the head is too light to carry a camera steadily (experience), and an f/10 achromat puts a violet halo round bright stars.
- Serious deep-sky imaging
No. A slow achromat on a light manual head is not an imaging instrument.
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 a manual equatorial mount
What it does well
- Sealed tube: no collimation, ever
- Once the mount is aligned roughly on the pole, one slow-motion knob follows a planet at high power
- At f/10 the violet fringe around the Moon and bright planets stays small for an achromat
What it costs you
- 70–90 mm is not much light: a 90 mm gathers (90 ÷ 130)² ≈ 0.48 of a 130 mm's, arithmetic. Deep sky is a short list
- Pointed high, a 90 cm tube on an equatorial head puts the eyepiece low, down among the tripod legs
- About 12 kg in three pieces, and a rough alignment on the pole every night
Worth knowing about this model
A manual equatorial on the EQ3-2 head: pointed roughly at the celestial pole, it follows the sky with one knob. The 10 mm eyepiece gives 90× on 90 mm, an exit pupil of 1 mm; higher powers need a shorter eyepiece or a Barlow, and the spec table lists neither.
Everything about 70–90 mm refractor on a manual equatorial mount →
Same family, other sizes
Read next
- Refractor or reflector for a first telescope?For the same money a reflector gives two to three times the aperture. When that decides, and the two cases where it does not.Updated 30 Aug 2026
- Which telescope should a beginner buy?The short answer, the three things the box does not say, then the detail by budget and by situation.Updated 24 Sept 2026
€479seen 7 Oct 2026 at Astroshop
Where to buy