What it shows
Through the family's typical instrument: 175 mm at f/6.5, with the eyepiece a beginner would use for each target. Computed, then darkened by the sky — never a photograph.
- The MoonDetailed57× (20 mm eyepiece) · 175 mm · 3.1 mm exit pupil
- SaturnDetailed190× (6 mm eyepiece) · 175 mm · 0.9 mm exit pupil
- The Hercules ClusterRecognisable114× (10 mm eyepiece) · 175 mm · 1.5 mm exit pupil
- The Whirlpool GalaxyRecognisable57× (20 mm eyepiece) · 175 mm · 3.1 mm exit pupil
Photo credits
These thumbnails are built from real photographs, scaled and darkened by the same arithmetic as the large view.
Which level of detail a target reaches is a rule of thumb from observers; the magnification, field and exit pupil are arithmetic.
What it is for, goal by goal
Every score with the sentence behind it, highest first.
- Deep sky5/5 ExcellentThe classic answer. Aperture is what deep-sky observing is short of, and this is where it stops being expensive.
- Moon & planets4/5 GoodPlenty of resolution. You will be nudging it along by hand every thirty seconds at high power.
- Sun4/5 GoodIn white light: sunspots with their penumbra, faculae near the edge, and granulation on a steady morning. Dawes' limit on the Sun: 0.8″ (116 ÷ 150 mm, arithmetic). Some models in this family come with the maker's solar filter, not all. Each model's page says whether its box has one. Every time: certified filter over the front · finder capped · never an eyepiece filter · an adult with children · never without the filter · measure first.
- Learn the sky3/5 FairStar-hopping with a finder works well, but the field is narrower than binoculars.
- With a child2/5 WeakThe eyepiece height wanders between standing and kneeling as you move around the sky.
Not for this
- Travel1/5 PoorIt goes in a car and nowhere else.
Not scored: Photo, Serious photo.
What it does well
- Enough aperture that globular clusters resolve into stars rather than staying fuzz
- No mount to align: push it, and it stays where you left it
- Nothing electronic to fail at −2 °C
What it costs you
- Two trips outside, or one heavy one. This is what decides whether it gets used
- The base is bulky in a way the tube is not — storage is the real constraint
- Useless on a balcony: it cannot swing past a railing or reach anything high
The Sun, safely
The Sun with this family
Some models in this family come with the maker's solar filter, not all. Each model's page says whether its box has one.
In white light: sunspots with their penumbra, faculae near the edge, and granulation on a steady morning. Dawes' limit on the Sun: 0.8″ (116 ÷ 150 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).
- 150 mm: outside diameter not sourced — once measured, one of: Omegon Helievo 152 (144–168 mm), Omegon Helievo 172 (164–188 mm), Omegon Helievo 192 (184–208 mm), euro EMC SF100 (187–221 mm) (€89–€125).
- 200 mm: outside diameter not sourced — once measured, one of: Omegon Helievo 192 (184–208 mm), euro EMC SF100 (187–221 mm), euro EMC SF100 (215–273 mm) (€109–€163).
The listing names no standard; no international standard exists for filters on telescopes, binoculars or lenses (AAS).
Counted against this family: €125, the filter for its smallest model — its cheapest route, where its price band starts.
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
Next to it
Smaller
130 mm tabletop Dobsonian- −35 mm
- −14 kg
- −€180 at entry level
Recognisable targets (of 14): countryside 14 → 14, city 10 → 10.
Same budget, another way
72–80 mm ED refractor- −99 mm
- −15 kg
- +€70 at entry level
Recognisable targets (of 14): countryside 14 → 10, city 10 → 7.
Bigger
250–300 mm Dobsonian- +100 mm
- +20 kg
- +€470 at entry level
Recognisable targets (of 14): countryside 14 → 14, city 10 → 12.
Rule of thumb from observers, at each family's typical aperture.
The models
Each price is the cheapest one observed, with its date. Links marked paid link earn us a commission and cost you nothing extra; the list is ordered by price, then by name — never by what pays. How this site is funded
| Model | Aperture | Focal length | Weight | Eyepieces supplied | Cheapest observed | Buy |
|---|---|---|---|---|---|---|
 Sky-Watcher Skyliner 150P Classic | 150 mm | 1200 mm | 18 kg | 25 mm and 10 mm | €357seen 7 Oct 2026 at Astroshop | At Astroshoppaid link4 other sellers
|
 Bresser Messier 6" Dobson | 152 mm | 1200 mm | 19 kg | 25 mm and 9 mm | €359seen 7 Oct 2026 at Astroshop | At Astroshoppaid link4 other sellers
|
 Sky-Watcher Skyliner 200P | 200 mm | 1200 mm | 25 kg | 25 mm and 10 mm | €449seen 7 Oct 2026 at Astroshop | At Astroshoppaid link4 other sellers
|
Questions people ask
150 or 200 mm?
A 200 gathers (200 ÷ 150)² ≈ 1.8 times the light and resolves 0.58″ against 0.77″ (Dawes' limit, 116 ÷ D). But its tube is 1.2 m long and the whole thing goes out in two trips. If you can store it and carry it, take the 200; if either makes you hesitate, the 150 will go out more often — and that is what counts.
A Dobsonian in a flat?
Storing one, yes — the base takes more room than the tube. Using one on a balcony, no: it cannot aim over a railing and cannot reach high in the sky. It needs a garden, a yard, or a lift and a car.
What will I really see of deep sky?
Globular clusters resolved into stars, M51 as two round smudges under a good sky, the Ring Nebula as a small grey ring. In grey, never in colour. In a city, galaxies become hard: then the sky is the limit, not the telescope.
Should I get the GoTo version?
What a beginner lacks first is knowing where to look, and a red-dot finder with an atlas teaches that better than a motor. GoTo adds cost, batteries and an alignment every night. It makes sense for someone who already knows they dislike hunting.
Read next
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- 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