Telescope Comparison
Bresser Messier 8" Dobsonian vs Sky-Watcher Explorer 150PL
203mm versus 150mm — the aperture difference is the comparison.
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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 · £249
The sky-learner's equatorial scope
- 150mm newtonian reflector on a manual equatorial mount
- Good for: Moon, planets, bright star clusters and nebulae
- Setup includes rough polar alignment before observing — more steps than a simple alt-az
- Mount axes feel counterintuitive at first; users find they become natural after several sessions
- Keeps the door open for adding tracking motors and moving into astrophotography later
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 Explorer 150PL's f/8 provides more magnification per eyepiece — better for fine planetary detail.
Mount type
Bresser Messier 8" Dobsonian's Dobsonian is immediately intuitive — no alignment, push to aim, observe. Sky-Watcher Explorer 150PL's equatorial mount requires polar alignment before each session but tracks the sky as Earth rotates, keeping objects centred.
Weight (OTA)
Sky-Watcher Explorer 150PL's optical tube is 6.4kg lighter. Relevant if you plan to use it on multiple mounts or carry the tube to dark-sky sites separately.
Optical design
Bresser Messier 8" Dobsonian is a DOBSONIAN; Sky-Watcher Explorer 150PL is a Newtonian reflector (mirrors, needs occasional collimation). Different optical formulas produce different strengths — reflectors give more aperture per pound; refractors give sharper contrast and require no collimation.
At the eyepiece
Bresser
Bresser Messier 8" Dobsonian
The Moon fills the field at low power with more detail than you'll have time to explore on any given night. Saturn's rings are unmistakable from the first session; in good seeing, the Cassini Division — the dark gap between the A and B rings — is a genuine target at higher magnification. Jupiter shows two equatorial cloud bands clearly, the four Galilean moons changing position night to night. The Orion Nebula (M42) shows wide nebulosity with the Trapezium splitting cleanly into four points at 80×. The Hercules Cluster (M13) begins to resolve into individual stars at the outer edges at higher magnification. The Andromeda Galaxy (M31) fills a wide-field eyepiece; the bright core and inner disc are obvious, and on a dark night the dust lane becomes visible with careful looking. The Bresser Messier 8" Dobsonian gathers 1.8× more light than the Sky-Watcher Explorer 150PL — a difference that's marginal on bright targets but visible on fainter ones: dimmer galaxies, faint globular clusters, and extended nebulosity that sits below the threshold of the smaller aperture.
Sky-Watcher
Sky-Watcher Explorer 150PL
The Moon fills the field at low power with more detail than you'll have time to explore on any given night. Saturn's rings are unmistakable from the first session; in good seeing, the Cassini Division — the dark gap between the A and B rings — is a genuine target at higher magnification. Jupiter shows two equatorial cloud bands clearly, the four Galilean moons changing position night to night. The Orion Nebula (M42) shows clear structure — nebulosity spreading around the Trapezium, which splits at moderate power. The Andromeda Galaxy (M31) shows a concentrated core clearly. The Hercules Cluster (M13) shows some resolution at the edges at higher magnification.
The real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
Bresser Messier 8" Dobsonian
- You'll set the base down, drop the tube in, and be observing within minutes — no polar alignment, no counterweights, no fumbling with latitude bolts in the dark, just point and look.
- You'll see things the 150PL simply cannot show you: M51's spiral arms instead of a featureless smudge, M13 with stars resolved across its face rather than just hinted at, and galaxies like M81/M82 with enough light to reveal their different structures — that extra 53mm of aperture is the difference between detecting an object and actually seeing detail in it.
- You'll learn to nudge the scope constantly at high power because nothing tracks for you, but the Dobsonian motion is intuitive — push it where you want — and the dual-speed Crayford focuser means nailing sharp planetary focus is genuinely satisfying rather than an exercise in frustration.
Sky-Watcher Explorer 150PL
- You'll spend your first few sessions learning polar alignment and the quirks of an equatorial mount, but once you've got it, the slow-motion controls let you track a planet or double star smoothly at 200× — something the Dobsonian's push-nudge approach makes far more fiddly.
- You'll get crisp, high-contrast planetary views that punch above what the aperture might suggest, because the f/8 focal ratio is forgiving of cheaper eyepieces and slight collimation errors — you don't need a coma corrector, and stars stay sharp across more of the field.
- You'll save £100 up front, and the equatorial mount gives you a future upgrade path to motorised tracking if you want to dabble in basic planetary imaging — something the Dobsonian mount simply doesn't offer without starting over.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Bresser
Bresser Messier 8" Dobsonian
The base has no fine altitude control out of the box — heavier eyepieces can cause the tube to droop, and most owners end up adding a tension spring mod to fix the balance.
At f/5.9, coma distortion is visible at the edges of wide-angle eyepieces, so if you want clean star fields across the whole view, you're looking at adding a coma corrector that costs nearly as much as the supplied eyepieces you'll also want to replace.
Collimation shifts with every car journey and sometimes between sessions — if you don't learn to collimate quickly and check it every time, your planetary views will be noticeably soft, and the scope's potential goes to waste.
Sky-Watcher
Sky-Watcher Explorer 150PL
The EQ3-2 mount is marginal for a tube this long — wind gusts or even touching the focuser can set off vibrations that take several seconds to dampen, which is especially annoying when you're trying to observe planets at 200×.
No motor drive is included, so despite having an equatorial mount, you're still manually correcting drift at high magnification — you get the setup complexity of an EQ mount without the tracking benefit unless you buy a motor separately.
The supplied 6×30 finder is dim and narrow, making it genuinely difficult to locate fainter targets — most owners replace it with a red-dot or Telrad almost immediately, adding an unplanned early cost.
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 observing to actually feel rewarding — not just ticking off faint smudges, but seeing spiral arms in galaxies and resolved stars in globular clusters. You don't mind a scope that takes up real space in the car and the living room, because on a clear night you want the most light-gathering power your budget allows. You're happy with a simple push-to setup that needs no power and no alignment procedure, and you'd rather spend your time at the eyepiece than wrestling with a mount. If you're a family, a club member, or a beginner who wants to be genuinely stunned by what's up there, this is where your £349 goes furthest.
The sky-learner's equatorial scope
Sky-Watcher · Sky-Watcher Explorer 150PL
You're drawn to the Moon and planets more than to faint fuzzies, and you want an evening where you park on Saturn's rings or split a tight double star and just savour the view. You'd rather learn the discipline of an equatorial mount now — polar aligning, using slow-motion cables — because you can see yourself adding a motor drive later and maybe trying planetary imaging. You're comfortable trading deep-sky reach for sharper, higher-contrast planetary views at a lower price, and you appreciate that the f/8 focal ratio means less fuss with collimation and no need for a coma corrector. This isn't for you if wide-field sweeping or galaxy hunting is the priority — but if the Moon and planets are your first love, the 150PL delivers where it matters.
Our verdict
At £249 versus £349, the Bresser Messier 8" Dobsonian costs 40% more. It delivers 53mm more aperture — a real and visible advantage on faint targets.
If budget is a genuine constraint, the Sky-Watcher Explorer 150PL 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 Explorer 150PL, use it for a year, then upgrade knowing exactly what you want.
Bresser Messier 8" Dobsonian
View Bresser Messier 8" Dobsonian →Sky-Watcher Explorer 150PL
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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 Explorer 150PL |
|---|---|---|
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 | Newtonian Reflector |
Coatings Better coatings = more light transmission through the optics | Parabolic primary mirror, fully coated | Parabolic primary mirror with multi-coated optics |
How do you point it?
| Spec | Bresser Messier 8" Dobsonian | Sky-Watcher Explorer 150PL |
|---|---|---|
Mount Type The mechanical system that holds and moves the telescope | Dobsonian | Equatorial |
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 Explorer 150PL |
|---|---|---|
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 Explorer 150PL |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 11.5kg | 5.1kg |
Total Weightⓘ Full setup including mount — this is what you lug to the car | 17.5kg | 14kg |
Tube Length | 1200mm | 900mm |
Tube Material | Steel | Steel |
What's in the box?
| Spec | Bresser Messier 8" Dobsonian | Sky-Watcher Explorer 150PL |
|---|---|---|
Eyepieces Included eyepieces — more is better, but quality matters more than quantity | 25mm and 10mm eyepieces | 25mm and 10mm Kellner |
Finder Scope Helps you locate areas of the sky before switching to the main eyepiece | 8x50 right-angle finder | 6x30 optical finder scope |
Diagonal Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Blue highlight: Bresser Messier 8" Dobsonian advantage · Amber highlight: Sky-Watcher Explorer 150PL advantage · Greyed cells: equal or subjective.