Telescope Comparison
Bresser Messier 8" Dobsonian vs Sky-Watcher Skyliner 150P
203mm versus 150mm — the aperture difference is the comparison.
First light
Bresser · 203mm · £349
The maximum-aperture visual reflector
- 203mm Newtonian on a floor-standing Dobsonian alt-az rocker box
- Good for: full visual programme — planets, Moon, globular clusters, galaxies, nebulae
- No alignment required — set up and observe in under 10 minutes
- No motorised tracking — targets drift at high magnification as Earth rotates
- 17.5kg total — designed for a fixed garden or regular dark-sky site, not casual transport
Sky-Watcher · 150mm · £229
The maximum-aperture visual reflector
- 150mm Newtonian on a floor-standing Dobsonian alt-az rocker box
- Good for: full visual programme — planets, Moon, globular clusters, galaxies, nebulae
- No alignment required — set up and observe in under 10 minutes
- No motorised tracking — targets drift at high magnification as Earth rotates
- 13kg total — designed for a fixed garden or regular dark-sky site, not casual transport
The full picture
The numbers that separate these two scopes — and what they mean at the eyepiece.
Aperture
Bresser Messier 8" Dobsonian gathers 1.8× more light. On bright targets — Moon, Saturn, Jupiter — you won't notice. On fainter targets — dim galaxies, faint globular clusters — the gap is real.
Focal length
Same focal length — identical magnification with any given eyepiece. Differences come from optical design and coatings.
Focal ratio
Bresser Messier 8" Dobsonian's faster f/5.91 delivers wider fields with any eyepiece — better for open clusters and large nebulae. Sky-Watcher Skyliner 150P's f/8 provides more magnification per eyepiece — better for fine planetary detail.
Mount type
Same mount type — setup experience and ergonomics will be similar. Differences lie in build quality and included accessories.
Weight (OTA)
Sky-Watcher Skyliner 150P's optical tube is 4.7kg lighter. Relevant if you plan to use it on multiple mounts or carry the tube to dark-sky sites separately.
Optical design
Same optical design — differences between these scopes come from aperture, mount, and focal ratio.
At the eyepiece
| Target | Bresser Messier 8" Dobsonian | Sky-Watcher Skyliner 150P |
|---|---|---|
| Planets | ||
| Moon | Excellent 203mm aperture resolves craters down to a few kilometres; the dual-speed focuser helps nail sharp focus at high power | Excellent 150mm aperture and f/8 focal ratio reward high magnification — craters, rilles, and shadow detail are crisp and high-contrast |
| Saturn | Excellent Cassini Division visible in steady seeing, cloud banding on the disc, and several moons including Titan easily spotted | Excellent 150mm and 1200mm focal length put this squarely in the top tier — rings well-defined, Cassini Division visible in good seeing |
| Jupiter | Excellent Multiple cloud belts, Great Red Spot, and all four Galilean moons with shadow transits visible | Excellent Multiple cloud bands, GRS, and Galilean moon shadow transits visible at 150–200x |
| Mars | Good Polar cap and dark surface features visible at opposition; the 1200mm focal length allows useful magnification with a short eyepiece | Good 150mm shows the disc clearly at opposition with polar cap and dark surface markings; needs very steady seeing |
Deep sky | ||
| Orion Nebula (M42) | Excellent Bright layered nebulosity with Trapezium resolved; 1200mm focal length crops the widest extent but detail in the core is superb | Excellent 150mm gathers plenty of light for nebulosity and the Trapezium; the 1200mm focal length crops the outermost extent but core detail is superb |
| Andromeda Galaxy (M31) | Moderate 1200mm focal length shows the bright core and inner disc well, but the full 3° extent of the galaxy is cropped even with a wide-field 2" eyepiece | Moderate 1200mm focal length shows only the bright core and inner halo — the full 3° extent of the galaxy is well beyond the field of view |
| Open clusters | Moderate Compact clusters like the Double Cluster look fine, but large sprawling clusters like the Pleiades overfill the field at 1200mm | Moderate Narrower field means large clusters like the Pleiades overfill the view; compact clusters like M35 and the Double Cluster fare better |
| Globular clusters | Excellent 203mm resolves individual stars across the outer regions of M13 and M5; a defining strength of this aperture class | Good 150mm begins resolving individual stars at the edges of M13 and M92 — a clear step up from smaller scopes |
| Faint galaxies | Good Galaxy groups like the Leo Triplet and Virgo Cluster members are within reach; spiral arm hints visible in M51 under dark skies | Good 150mm pulls in galaxies like M81, M82, M51, and M104 as soft glows with hints of structure under dark skies |
| Milky Way / wide field | Not recommended 1200mm focal length is far too narrow for sweeping star fields — a wide-field refractor or binoculars serve this purpose better | Not recommended 1200mm focal length gives too narrow a field for sweeping star fields — a job better suited to binoculars or short-tube scopes |
Other | ||
| Double stars | Excellent 203mm aperture resolves doubles down to about 0.6 arcseconds; Dawes limit easily splits Albireo, the Double Double in Lyra, and many tighter pairs | Excellent 150mm aperture and long f/8 focal ratio produce clean Airy discs — splits close pairs like Albireo, Epsilon Lyrae, and Castor easily |
| Astrophotography (deep sky) | Not recommended No tracking means exposures beyond a second or two trail; manual Dobsonian mount is unsuitable for deep-sky imaging | Not applicable |
| Astrophotography (planetary) | Moderate Planetary video capture with a high-speed camera is feasible — 203mm aperture and 1200mm focal length give a usable image scale, but manual tracking makes it fiddly | Not applicable |
The real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
Bresser Messier 8" Dobsonian
- You'll see genuinely more — that extra 53mm of aperture means M13 resolves into individual stars at the edges, M51's spiral arms emerge under dark skies, and faint galaxies stop being vague smudges and start showing structure you can actually describe.
- You'll reach for the dual-speed Crayford focuser on every planetary session and be grateful it's there — dialling in the Cassini Division at 200× is a fingertip refinement, not the overshoot-and-backtrack game you play with a single-speed rack-and-pinion.
- You'll pay for the aperture in bulk: the 20kg assembled weight and 1.2m tube mean every session is a deliberate decision, not a spontaneous one, and you'll need a cool-down period before the views settle.
Sky-Watcher Skyliner 150P
- You'll find yourself using this scope more often than you'd expect — it's still a big tube, but the lighter weight makes the difference between carrying it out on a weeknight and leaving it in the cupboard.
- You'll be rewarded on planets: the f/8 focal ratio is more forgiving of cheaper eyepieces and less bothered by coma than the Bresser's faster f/5.9 cone, so Saturn's rings and Jupiter's belts look crisp without needing a coma corrector or premium glass.
- You'll hit the aperture ceiling on deep-sky nights — globulars look granular rather than resolved, and galaxies like M51 stay as soft glows rather than revealing spiral structure, which is exactly where the Bresser pulls ahead.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Bresser
Bresser Messier 8" Dobsonian
The Dobsonian base lacks fine altitude adjustment out of the box — heavier eyepieces can cause the tube to drop, and you'll likely end up adding a tension spring mod to keep things balanced.
At f/5.9, coma distortion is visible at the edges of wide-angle eyepieces, so budget for a coma corrector if pinpoint stars across the whole field matter to you.
The supplied 25mm and 9mm eyepieces are adequate but noticeably hold back what the optics can deliver — plan on spending another £40–80 on at least one decent eyepiece early on.
Sky-Watcher
Sky-Watcher Skyliner 150P
The 1200mm focal length at f/8 limits your widest true field to about 1° — you cannot frame the full extent of M31 or do meaningful Milky Way sweeping, which is a real constraint on what this scope feels good at.
The included 25mm and 10mm Plössl eyepieces are basic and noticeably improve with aftermarket replacements — the scope deserves better glass than it ships with.
The tube is over a metre long and the rocker box is bulky, so despite being lighter than the Bresser, it's still not something you'll toss in a car on a whim or use on a balcony.
Which is right for you?
Two different buyers. Two different right answers.
The maximum-aperture visual reflector
Bresser · Bresser Messier 8" Dobsonian
You want deep-sky to actually look like deep-sky — resolved globular clusters, spiral arms in galaxies, layered nebulosity — and you're willing to wrestle with a bigger tube to get there. You're a beginner or intermediate observer who's committed to visual astronomy, you have storage space and a car boot that can handle 1.2 metres of telescope, and you'd rather spend your budget on aperture now than on tracking you don't need yet. You'll appreciate the dual-speed focuser the first time you try to nail focus on Saturn at 250×. This isn't for you if astrophotography is the goal, if you live in a flat with only balcony access, or if you know you'll skip sessions when setup takes more than five minutes.
The maximum-aperture visual reflector
Sky-Watcher · Sky-Watcher Skyliner 150P
You're starting out, you want a real telescope that stands on the ground and shows you planets with genuine detail, and you'd rather save £120 for eyepiece upgrades or a Telrad finder than chase the last increment of deep-sky performance. You'll use this scope most on the Moon, Jupiter, and Saturn, and its forgiving f/8 focal ratio means the views are sharp without fussing over coma or premium eyepieces. This isn't for you if you already know you want to chase faint galaxies under dark skies — the 150mm aperture will leave you wanting more — or if wide-field sweeping is a priority, because the narrow field of view at 1200mm focal length works against you there.
Our verdict
At £229 versus £349, the Bresser Messier 8" Dobsonian costs 52% more. It delivers 53mm more aperture — a real and visible advantage on faint targets.
If budget is a genuine constraint, the Sky-Watcher Skyliner 150P will make you a happy observer. The Bresser Messier 8" Dobsonian's optical advantage on faint targets is real and you are unlikely to regret it if you can stretch. If I had to choose without knowing your situation: start with the Sky-Watcher Skyliner 150P, use it for a year, then upgrade knowing exactly what you want.
Bresser Messier 8" Dobsonian
View Bresser Messier 8" Dobsonian →Sky-Watcher Skyliner 150P
View Sky-Watcher Skyliner 150P →Deep field: Full specifications
Every data point, for those who want to go further.
Full specifications
Fields highlighted in blue or amber indicate the better value for that spec. Data is manufacturer-stated and may vary.
How much can it see?
| Spec | Bresser Messier 8" Dobsonian | Sky-Watcher Skyliner 150P |
|---|---|---|
Apertureⓘ The most important spec — bigger = more light = better views | 203mm | 150mm |
Focal Length Longer = more magnification potential | 1200mm | 1200mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/5.91 | f/8 |
Optical Design The type of optics — each design has different strengths | Dobsonian | Dobsonian |
Coatings Better coatings = more light transmission through the optics | Parabolic primary mirror, fully coated | Parabolic primary mirror, fully multi-coated |
How do you point it?
| Spec | Bresser Messier 8" Dobsonian | Sky-Watcher Skyliner 150P |
|---|---|---|
Mount Type The mechanical system that holds and moves the telescope | Dobsonian | Dobsonian |
GoTo Computer-controlled pointing — finds any of thousands of objects automatically | ||
Tracking Motor keeps objects centred as the Earth rotates — essential for astrophotography |
The focuser
| Spec | Bresser Messier 8" Dobsonian | Sky-Watcher Skyliner 150P |
|---|---|---|
Focuser Size 2" accepts wider eyepieces and gives better low-power views | 2" | 1.25" |
Focuser Type Rack-and-pinion is standard; Crayford and dual-speed are smoother | Dual-speed Crayford (2" with 1.25" adapter) | Rack and pinion |
Size & weight
| Spec | Bresser Messier 8" Dobsonian | Sky-Watcher Skyliner 150P |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 11.5kg | 6.8kg |
Total Weightⓘ Full setup including mount — this is what you lug to the car | 17.5kg | 13kg |
Tube Length | 1200mm | 1150mm |
Tube Material | Steel | Steel |
What's in the box?
| Spec | Bresser Messier 8" Dobsonian | Sky-Watcher Skyliner 150P |
|---|---|---|
Eyepieces Included eyepieces — more is better, but quality matters more than quantity | 25mm and 10mm eyepieces | 25mm and 10mm Super eyepieces |
Finder Scope Helps you locate areas of the sky before switching to the main eyepiece | 8x50 right-angle finder | 6x30 optical finder |
Diagonal Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Blue highlight: Bresser Messier 8" Dobsonian advantage · Amber highlight: Sky-Watcher Skyliner 150P advantage · Greyed cells: equal or subjective.