Telescope Comparison
Bresser Messier 12" Dobsonian vs Explore Scientific 12" Dobsonian
The specs are close. The experience isn't.
First light
Bresser · 305mm · £699
The maximum-aperture visual reflector
- 305mm 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
- 42kg total — designed for a fixed garden or regular dark-sky site, not casual transport
Explore Scientific · 305mm · £999
The maximum-aperture visual reflector
- 305mm 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
- 34kg 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
Equal light-gathering. Aperture won't settle this comparison — the mount, focal ratio, and observing experience are what differ.
Focal length
Bresser Messier 12" Dobsonian's longer focal length reaches higher magnification with the same eyepiece — better reach for planetary detail. Explore Scientific 12" Dobsonian's shorter focal length gives a wider true field — better for large open clusters and extended nebulae.
Focal ratio
Same focal ratio — the same eyepiece gives equivalent magnification and true field in both scopes.
Mount type
Same mount type — setup experience and ergonomics will be similar. Differences lie in build quality and included accessories.
Weight (OTA)
Explore Scientific 12" Dobsonian's optical tube is 5.0kg 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 12" Dobsonian | Explore Scientific 12" Dobsonian |
|---|---|---|
| Planets | ||
| Moon | Excellent 305mm aperture delivers overwhelming detail — craterlets, rilles, and shadow play at 200–300×; a neutral density filter helps manage brightness | Excellent 305mm aperture delivers overwhelming lunar detail — sub-kilometre crater features, rilles, and shadow play at high magnification |
| Saturn | Excellent Cassini Division easily visible, Crepe Ring and cloud banding on the disc accessible in steady seeing at 250×+ | Excellent 305mm aperture and 1524mm focal length show the Cassini Division cleanly, globe banding, and multiple moons |
| Jupiter | Excellent Multiple cloud belts, festoons, the Great Red Spot, and moon shadow transits visible; 1525mm focal length supports high magnification well | Excellent Multiple cloud belts, festoons, the Great Red Spot, and moon shadow transits visible in steady seeing |
| Mars | Excellent At 305mm and 1525mm focal length, dark albedo features, polar caps, and occasional dust storm effects visible near opposition | Excellent 305mm aperture at 1524mm focal length reveals dark albedo features and polar caps at opposition |
Deep sky | ||
| Orion Nebula (M42) | Excellent Trapezium cleanly split, extensive nebulosity with hints of colour; 1525mm focal length crops the widest extent but detail is superb | Excellent Massive light grasp shows layered nebulosity with hints of colour; Trapezium E and F stars visible on good nights |
| Andromeda Galaxy (M31) | Moderate 1525mm focal length shows only the bright core and inner disc — too narrow to frame the full 3° extent; dust lanes visible but outer halo is cropped | Moderate 1524mm focal length crops the 3° extent to the bright core and inner dust lanes — full halo is beyond the field of view |
| Open clusters | Moderate 1525mm focal length means larger clusters like the Double Cluster overfill the field; compact clusters like M37 are well-served | Moderate Long focal length limits the field of view — larger clusters like the Double Cluster overfill the field, though compact clusters are striking |
| Globular clusters | Excellent 305mm resolves individual stars across the core of M13, M3, and M5 — one of this scope's signature strengths | Excellent 305mm resolves individual stars across the full extent of clusters like M13 and M92, including their dense cores |
| Faint galaxies | Excellent 305mm pulls in galaxies to mag 14+; spiral arm structure visible in M51, NGC 891's dust lane detectable from dark sites | Excellent 305mm of aperture reveals spiral arms in M51, dust lanes in edge-on galaxies, and populates the Virgo Cluster with dozens of members |
| Milky Way / wide field | Not recommended 1525mm focal length gives far too narrow a field for sweeping star fields — a separate wide-field instrument is needed | Not recommended 1524mm focal length produces far too narrow a field for sweeping Milky Way star fields |
Other | ||
| Double stars | Excellent 305mm resolves pairs under 0.5 arcsecond; f/5 is faster than ideal for tight doubles but a Barlow sharpens the Airy disc at high power | Excellent 305mm aperture gives a Dawes limit of ~0.38 arcseconds; long focal length supports high magnification for tight pairs |
| Astrophotography (deep sky) | Not recommended Manual Dobsonian mount has no tracking — long exposures are not possible | Not applicable |
| Astrophotography (planetary) | Moderate Lucky imaging with a high-speed camera is technically possible at 305mm, but manual tracking makes it difficult to keep targets centred; results are inconsistent | Good 305mm aperture and 1524mm focal length suit high-resolution planetary video capture, though manual tracking limits frame consistency |
The real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
Bresser Messier 12" Dobsonian
- You're getting the same 305mm aperture and f/5 optical formula as the Explore Scientific for £300 less — the views of M13's resolved core and the Veil Nebula's filaments will be effectively identical, so you'll pocket the difference for a coma corrector and better eyepieces that actually matter.
- You'll wrestle with approximately 42kg of total setup weight, and the Bresser's included eyepieces are serviceable but forgettable — expect to budget another £100–150 on a decent wide-field eyepiece before your second session.
- Your observing rhythm is the same manual push-to workflow as any untracked Dob: collimate, cool down for 30–60 minutes, star-hop to your target, and nudge the tube every 30 seconds at 250×. The savings here buy gear, not convenience.
Explore Scientific 12" Dobsonian
- You're paying a £300 premium for what is optically a near-identical 305mm f/5 Newtonian — the galaxies, globulars, and planetary detail you'll see through either scope are indistinguishable on any given night of seeing.
- The dual-speed Crayford focuser is where you'll feel the difference most tangibly: dialling in sharp focus on Saturn's Cassini Division or lunar rilles is noticeably smoother and more precise than a single-speed unit, and that matters every single session.
- You'll still haul a heavy tube and base to your dark site, still collimate before every session, and still manually track everything — the extra spend doesn't change the fundamental ownership rhythm, it refines the mechanical experience at the eyepiece.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Bresser
Bresser Messier 12" Dobsonian
At a reported 42kg total weight, you need a vehicle with real cargo space and ideally a second pair of hands — this is not a scope you casually load into a hatchback.
The included Plössl-type eyepieces are a bottleneck on a 305mm mirror — you'll see soft edges and underwhelming fields of view until you upgrade, effectively adding to the headline price.
f/5 coma is visible in the outer 30% of wide-angle eyepieces, so a coma corrector isn't optional if you plan to use anything wider than a basic Plössl.
Explore Scientific
Explore Scientific 12" Dobsonian
At £999 it's significantly more expensive than the Bresser while delivering the same aperture, focal ratio, and manual-only operation — you need to value the mechanical refinements to justify the gap.
Collimation is critical at f/5 and required before every session — if you don't own a collimation tool and aren't comfortable using one, your first nights will be frustrating rather than rewarding.
Cool-down time for the 12-inch mirror runs 30–60 minutes, and if your model doesn't include a mirror cell fan, you'll want to add one yourself to avoid tube currents degrading planetary views.
Which is right for you?
Two different buyers. Two different right answers.
The maximum-aperture visual reflector
Bresser · Bresser Messier 12" Dobsonian
You want the most aperture you can buy for under £700, and you're comfortable spending the savings on a coma corrector, a quality wide-field eyepiece, and a collimation tool — because you know the included accessories won't do justice to a 12-inch mirror. You're an intermediate observer who already star-hops confidently, you have a car that can swallow 42kg of telescope, and you'd rather invest in glass and filters than pay extra for a marginally nicer focuser. This isn't for you if you want a polished out-of-the-box experience or lack the storage and transport to handle a full-size Dobsonian.
The maximum-aperture visual reflector
Explore Scientific · Explore Scientific 12" Dobsonian
You value a refined mechanical experience at the eyepiece — particularly the dual-speed Crayford focuser — and you're willing to pay £300 more for build quality you'll appreciate every time you rack focus on a planet or double star. You're an experienced visual observer who already owns decent eyepieces and a coma corrector, so the total cost of ownership matters less than the nightly quality of use. This isn't for you if you're on a tight budget and would rather put that £300 toward accessories that directly improve the view, since optically these two scopes are functionally the same telescope.
Our verdict
At £699 versus £999, the Explore Scientific 12" Dobsonian costs 43% more. The extra money buys a more capable mount and better build quality, not larger optics.
For most buyers starting out, the Bresser Messier 12" Dobsonian is the sensible choice — put the savings into a better eyepiece. The Explore Scientific 12" Dobsonian makes sense once you know exactly why you need what it offers. If I had to choose: the Bresser Messier 12" Dobsonian, and spend the difference on a quality eyepiece.
Bresser Messier 12" Dobsonian
View Bresser Messier 12" Dobsonian →Explore Scientific 12" Dobsonian
View Explore Scientific 12" Dobsonian →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 12" Dobsonian | Explore Scientific 12" Dobsonian |
|---|---|---|
Aperture The most important spec — bigger = more light = better views | 305mm | 305mm |
Focal Length Longer = more magnification potential | 1525mm | 1524mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/5 | f/4.99 |
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 coated |
How do you point it?
| Spec | Bresser Messier 12" Dobsonian | Explore Scientific 12" Dobsonian |
|---|---|---|
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 12" Dobsonian | Explore Scientific 12" Dobsonian |
|---|---|---|
Focuser Size 2" accepts wider eyepieces and gives better low-power views | 2" | 2" |
Focuser Type Rack-and-pinion is standard; Crayford and dual-speed are smoother | Dual-speed Crayford (2" with 1.25" adapter) | Dual-speed Crayford (10:1 reduction) |
Size & weight
| Spec | Bresser Messier 12" Dobsonian | Explore Scientific 12" Dobsonian |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 27kg | 22kg |
Total Weightⓘ Full setup including mount — this is what you lug to the car | 42kg | 34kg |
Tube Length | 1525mm | 1500mm |
Tube Material | Steel | Steel |
What's in the box?
| Spec | Bresser Messier 12" Dobsonian | Explore Scientific 12" Dobsonian |
|---|---|---|
Eyepieces Included eyepieces — more is better, but quality matters more than quantity | 25mm and 10mm eyepieces | 25mm eyepiece |
Finder Scope Helps you locate areas of the sky before switching to the main eyepiece | 8x50 right-angle finder | 8x50 right-angle finder |
Diagonal Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Blue highlight: Bresser Messier 12" Dobsonian advantage · Amber highlight: Explore Scientific 12" Dobsonian advantage · Greyed cells: equal or subjective.