Telescope Comparison
Bresser Messier 10" Dobsonian vs Bresser Messier 8" Dobsonian
254mm versus 203mm — the aperture difference is the comparison.
First light
Bresser · 254mm · £499
The maximum-aperture visual reflector
- 254mm 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
- 27kg total — designed for a fixed garden or regular dark-sky site, not casual transport
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
The full picture
The numbers that separate these two scopes — and what they mean at the eyepiece.
Aperture
Bresser Messier 10" Dobsonian gathers 1.6× 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
Bresser Messier 10" Dobsonian's longer focal length reaches higher magnification with the same eyepiece — better reach for planetary detail. Bresser Messier 8" Dobsonian's shorter focal length gives a wider true field — better for large open clusters and extended nebulae.
Focal ratio
Bresser Messier 10" Dobsonian's faster f/5 delivers wider fields with any eyepiece — better for open clusters and large nebulae. Bresser Messier 8" Dobsonian's f/5.91 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)
Bresser Messier 8" Dobsonian's optical tube is 6.5kg 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 10" Dobsonian | Bresser Messier 8" Dobsonian |
|---|---|---|
| Planets | ||
| Moon | Excellent 254mm resolves sub-kilometre crater detail; the terminator is spectacular with hundreds of features visible per session | Excellent 203mm aperture resolves craters down to a few kilometres; the dual-speed focuser helps nail sharp focus at high power |
| Saturn | Excellent Cassini Division cleanly split, cloud banding on the globe visible, and multiple moons in the field at 1270mm focal length | Excellent Cassini Division visible in steady seeing, cloud banding on the disc, and several moons including Titan easily spotted |
| Jupiter | Excellent Multiple cloud belts, festoons, GRS detail, and moon shadow transits all accessible at 200x+ in steady seeing | Excellent Multiple cloud belts, Great Red Spot, and all four Galilean moons with shadow transits visible |
| Mars | Excellent 254mm aperture and 1270mm focal length (extendable with Barlows to 2500mm+) reveal dark albedo features, polar caps, and limb phenomena at opposition | Good Polar cap and dark surface features visible at opposition; the 1200mm focal length allows useful magnification with a short eyepiece |
Deep sky | ||
| Orion Nebula (M42) | Excellent Bright nebulosity fills the field with structure and hints of colour; the Trapezium cluster is cleanly resolved into four or more stars | Excellent Bright layered nebulosity with Trapezium resolved; 1200mm focal length crops the widest extent but detail in the core is superb |
| Andromeda Galaxy (M31) | Good 1270mm focal length captures the bright core and inner disc well but crops the full 3° extent; dust lanes visible with averted vision | 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 |
| Open clusters | Good 1270mm focal length means larger clusters like the Double Cluster just fit the field with a wide-angle 2-inch eyepiece; compact clusters like M37 are stunning | Moderate Compact clusters like the Double Cluster look fine, but large sprawling clusters like the Pleiades overfill the field at 1200mm |
| Globular clusters | Excellent 254mm resolves individual stars across the face of M13, M3, and M92 — not just at the edges but into the core region | Excellent 203mm resolves individual stars across the outer regions of M13 and M5; a defining strength of this aperture class |
| Faint galaxies | Excellent Spiral arms in M51, dust lanes in M82, and structure in dozens of NGC galaxies become accessible under dark skies | Good Galaxy groups like the Leo Triplet and Virgo Cluster members are within reach; spiral arm hints visible in M51 under dark skies |
| Milky Way / wide field | Moderate 1270mm focal length limits the true field even with a 2-inch eyepiece; individual star clouds are impressive but you cannot sweep wide swathes | Not recommended 1200mm focal length is far too narrow for sweeping star fields — a wide-field refractor or binoculars serve this purpose better |
Other | ||
| Double stars | Excellent 254mm gives a Dawes limit around 0.46 arcseconds — tight pairs like Porrima and Castor are cleanly split; f/5 may show slight diffraction effects vs longer focal ratios | 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 |
| Astrophotography (deep sky) | Not recommended Manual Dobsonian mount provides no tracking — long-exposure imaging is not possible without aftermarket equatorial platform | Not recommended No tracking means exposures beyond a second or two trail; manual Dobsonian mount is unsuitable for deep-sky imaging |
| Astrophotography (planetary) | Challenging Short video captures of bright planets are possible with a webcam, but manual tracking at 200x+ is very difficult and results are inconsistent | 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 |
The real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
Bresser Messier 10" Dobsonian
- You'll see spiral arms in M51, resolved stars across the face of M13, and festoons on Jupiter — that extra 50mm of aperture over the 8-inch turns 'I think I can see it' into 'I can definitely see it,' and on the best nights the difference is genuinely striking.
- You'll pay for that aperture every time you move the scope — at roughly 25kg assembled, you're wrestling five extra kilos into the car, and the base is proportionally bulkier, so you'll need more boot space and more patience at each end of the drive.
- You'll find the f/5 focal ratio punishes you harder with coma at the field edge than the 8-inch's f/5.9 — a coma corrector like the Baader MPCC goes from 'nice to have' to practically essential if you use wide-angle eyepieces, and the included eyepiece is a single basic Plössl that leaves you immediately shopping for upgrades.
Bresser Messier 8" Dobsonian
- You'll get 80% of the deep-sky performance of the 10-inch at a noticeably lower price and weight — M51's spiral arms are still there under dark skies, globulars still resolve at the edges, and you save £150 that can go straight into a better eyepiece.
- You'll appreciate the dual-speed Crayford focuser the moment you try to nail focus on Saturn's Cassini Division at 200× — it's a genuine quality-of-life upgrade over what the 10-inch ships with, and it means one less accessory to buy on day one.
- You'll still be manhandling a 1.2-metre tube and roughly 20kg of scope, so this isn't a grab-and-go experience either — but that five-kilo saving over the 10-inch makes a real difference when you're loading up alone in the dark at midnight.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Bresser
Bresser Messier 10" Dobsonian
At 25kg assembled with a tube roughly 1.2 metres long, you need an estate car or rear seats down — this scope does not fit casually in a hatchback boot alongside anything else.
The f/5 focal ratio produces noticeable coma at wide-field eyepiece edges, worse than the 8-inch's f/5.9, making a coma corrector an effectively required purchase that adds to the real cost.
The included eyepiece is typically a single 25mm Super Plössl — you'll need to budget immediately for both a high-power eyepiece and a low-power 2-inch eyepiece to access what this aperture can actually deliver.
Bresser
Bresser Messier 8" Dobsonian
The Dobsonian base lacks fine altitude adjustment out of the box — heavier eyepieces or accessories can cause the tube to drift, and a tension spring modification is a common fix owners end up performing.
No tracking means objects drift out of view in 30–60 seconds at high magnification — you'll spend your planetary sessions nudging the scope rather than staring at detail, and that gets tiring over a long evening.
The supplied 25mm and 9mm eyepieces are adequate but visibly limit the scope's performance — budget for at least one quality mid-range or high-power eyepiece soon after purchase to see what 203mm can really do.
Which is right for you?
Two different buyers. Two different right answers.
The maximum-aperture visual reflector
Bresser · Bresser Messier 10" Dobsonian
You already own a smaller scope and you know you love deep-sky observing — you've seen M13 as a fuzzy ball and M51 as a grey smudge, and you want to see them properly resolved. You have a car that can swallow a big tube, a dark-sky site you're willing to drive to, and you'd rather spend your budget on raw aperture than convenience features. You're comfortable with collimation and manual star-hopping, and you're prepared to buy a coma corrector and better eyepieces to get the most from this scope. This isn't for you if you want any kind of astrophotography, if you live in a flat with no storage, or if you need a scope you can set up and observe within five minutes.
The maximum-aperture visual reflector
Bresser · Bresser Messier 8" Dobsonian
You're buying your first serious telescope, or you want the most capable visual scope you can get without the weight and cost penalty of going to 10 inches. You like the idea of a scope that works straight out of the box with a decent focuser, and you'd rather put the £150 you save toward a quality eyepiece or a Telrad finder. You have space to store a big tube but you don't want every observing session to feel like a gym workout. This isn't for you if you want tracking, GoTo, or astrophotography — and it's not for you if you're certain you'll be chasing the faintest galaxy detail, because that extra 50mm of aperture in the 10-inch makes a real difference at the limit.
Our verdict
The Bresser Messier 8" Dobsonian is designed to get a new observer to the eyepiece quickly with minimal friction. The Bresser Messier 10" Dobsonian assumes you already know what you want from the sky, or are genuinely willing to put in the learning time.
If this is your first telescope, buy the Bresser Messier 8" Dobsonian. You'll spend a year learning what you actually want, and those lessons are cheaper at £349. The Bresser Messier 10" Dobsonian is the scope to buy when you've outgrown your first one and know exactly why you want it. If I had to choose for a first-time buyer: the Bresser Messier 8" Dobsonian.
Bresser Messier 10" Dobsonian
View Bresser Messier 10" Dobsonian →Bresser Messier 8" Dobsonian
View Bresser Messier 8" 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 10" Dobsonian | Bresser Messier 8" Dobsonian |
|---|---|---|
Apertureⓘ The most important spec — bigger = more light = better views | 254mm | 203mm |
Focal Length Longer = more magnification potential | 1270mm | 1200mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/5 | f/5.91 |
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 10" Dobsonian | Bresser Messier 8" 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 10" Dobsonian | Bresser Messier 8" 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 (2" with 1.25" adapter) |
Size & weight
| Spec | Bresser Messier 10" Dobsonian | Bresser Messier 8" Dobsonian |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 18kg | 11.5kg |
Total Weightⓘ Full setup including mount — this is what you lug to the car | 27kg | 17.5kg |
Tube Length | 1270mm | 1200mm |
Tube Material | Steel | Steel |
What's in the box?
| Spec | Bresser Messier 10" Dobsonian | Bresser Messier 8" Dobsonian |
|---|---|---|
Eyepieces Included eyepieces — more is better, but quality matters more than quantity | 25mm and 10mm eyepieces | 25mm and 10mm eyepieces |
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 10" Dobsonian advantage · Amber highlight: Bresser Messier 8" Dobsonian advantage · Greyed cells: equal or subjective.