130–150 mm Newtonian on a small GoTo alt-az mount
Sky-Watcher Explorer-130PS AZ-GTi
An ordinary telescope — a short 130 or 150 mm Newtonian — on a small motorised alt-az mount driven from a phone. It finds the target and keeps it in the field, and you still look through an eyepiece. It needs batteries and a star alignment every night, and it does the finding you might have wanted to learn.
€595seen 7 Oct 2026 at Astroshop
- 130 mmAperture
- f/5.0Focal ratio
- 6.7 kgTypical weight
- 22–260×Useful magnification
Should you buy it?
- Yes if what you mainly want is the moon and the planets: that is what this family does best.
- No if your priority is taking it with me, learn my way around the sky, 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)
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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 | 130 mm |
|---|---|
| Focal ratio | 650 mm · f/5.0 |
| Mount | AZ-GTi GoTo alt-az driven over Wi-Fi from a phone, aluminium tripod |
| Typical weight | 6.7 kg |
| Eyepieces | 25 mm and 10 mm |
| Useful magnification | 22× to 260× at 130 mm |
| Resolution (Dawes) | 0.9″ — the tightest double star this aperture can split |
| Faintest star, suburban sky | around magnitude 11.8 |
| Observed price | €595 seen 7 Oct 2026 at Astroshop |
Made for
- The Moon and the planets
130–150 mm, and the mount tracks: Saturn stays in the field at 150× on 150 mm (exit pupil 1 mm) instead of drifting out in under a minute (arithmetic, with a 50° eyepiece). Dawes' limit is 0.77″ on 150 mm (116 ÷ 150, arithmetic). The eyepieces in these kits stop at 65–75× on 130–150 mm (an exit pupil of 2 mm); more needs one bought separately.
- The Sun
In white light: sunspots with their penumbra, faculae near the edge, and granulation on a steady morning. Dawes' limit on the Sun: 0.9″ (116 ÷ 130 mm, arithmetic). Measure the outside diameter first, then one of: Omegon Helievo 132 (124–148 mm), Omegon Helievo 152 (144–168 mm), Omegon Helievo 172 (164–188 mm) (€79–€99). 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
- Taking it with me
A car trip: tube, mount head, tripod, batteries and a phone. Hand luggage, no.
- Learn my way around the sky
The GoTo does the part you said you wanted to learn. The app names what is up; it does not teach you to find it.
- First astrophotography
A phone at the eyepiece on the Moon, and short planetary videos, which tracking makes easier. Not long exposures: an alt-az mount rotates the field during the exposure, and these small mounts are not built to carry a camera (experience).
- Serious deep-sky imaging
No. Field rotation and a mount rated for about 5 kg rule out long exposures.
The Sun, safely
No solar filter in the box
The Sun with this model
No source we have states the outside diameter of its tube or dew shield. Measure it at the front, then take the cell whose range holds it. For 130 mm of aperture, one of these:
In white light: sunspots with their penumbra, faculae near the edge, and granulation on a steady morning. Dawes' limit on the Sun: 0.9″ (116 ÷ 130 mm, arithmetic).
Past about 100 to 125 mm, daytime air rather than aperture generally sets the limit on the Sun (experience: the AAVSO solar observing guide).
- Omegon Helievo 132 (124–148 mm): holds 124–148 mm, €79 (seen 26 Sept 2026) Astroshoppaid link
- Omegon Helievo 152 (144–168 mm): holds 144–168 mm, €89 (seen 26 Sept 2026) Astroshoppaid link
- Omegon Helievo 172 (164–188 mm): holds 164–188 mm, €99 (seen 26 Sept 2026) Astroshoppaid link
The listing names no standard; no international standard exists for filters on telescopes, binoculars or lenses (AAS).
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: 130–150 mm Newtonian on a small GoTo alt-az mount
What it does well
- Finds objects a town sky hides, and tracks them: a planet stays in the field at high power, and while others take turns
- Real aperture at the eyepiece — a 150 mm gathers (150 ÷ 7)² ≈ 460 times the light of a dark-adapted 7 mm pupil, arithmetic
- A standard dovetail: the tube and the mount can each be replaced later without the other
What it costs you
- Batteries — usually eight AA cells — and an alignment on one or two stars at the start of every night
- On most of these kits the phone is the hand controller: a flat phone battery ends the night
- Small mounts rated for about 5 kg: a 150 mm tube is near that limit, and at high power the view settles slowly after a touch (experience)
Worth knowing about this model
Runs on eight AA cells or 12 V, and the GoTo needs an alignment on two stars, or the brightest one, before it finds anything; a phone or tablet drives it over Wi-Fi. 6.7 kg in all. The 10 mm eyepiece gives 65× on 130 mm, an exit pupil of 2 mm; higher powers need a shorter eyepiece or a Barlow, and the spec table lists neither.
Everything about 130–150 mm Newtonian on a small GoTo alt-az mount →
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Read next
- Do you need a GoTo mount for a first telescope?At €500 the motor replaces half the mirror. Who that is a bad trade for, and the three people it is right for.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
€595seen 7 Oct 2026 at Astroshop
Where to buy