Telescope Comparison
Bresser Messier AR-102 vs Sky-Watcher Evostar 100ED
The Bresser Messier AR-102 is a complete setup. The Sky-Watcher Evostar 100ED needs a mount before it's usable.
First light
Bresser · 102mm · £299
The sky-learner's equatorial scope
- 102mm refractor 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
Sky-Watcher · 100mm · £449
The custom-rig optical tube
- 100mm refractor — optical tube only, no mount included
- 900mm focal length at f/9
- Requires a compatible mount before you can observe anything
- Best for: observers who already own a suitable mount or are building a specific imaging rig
- Not a complete purchase — budget at least £100–300 extra for a mount before observing
The full picture
The numbers that separate these two scopes — and what they mean at the eyepiece.
Aperture
Bresser Messier AR-102 gathers 1× 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
Sky-Watcher Evostar 100ED's longer focal length reaches higher magnification with the same eyepiece — better reach for planetary detail. Bresser Messier AR-102's shorter focal length gives a wider true field — better for large open clusters and extended nebulae.
Focal ratio
Bresser Messier AR-102's faster f/6.47 delivers wider fields with any eyepiece — better for open clusters and large nebulae. Sky-Watcher Evostar 100ED's f/9 provides more magnification per eyepiece — better for fine planetary detail.
Mount type
Sky-Watcher Evostar 100ED has no mount — add a compatible mount before you can observe. Bresser Messier AR-102 is a complete ready-to-use system.
Weight (OTA)
Similar optical tube weight. Any portability difference between these setups comes from the mount, not the tube itself.
Optical design
Both are refractors — no mirrors to collimate, good contrast, colour-free stars with ED or APO glass. The differences between them are in aperture, focal ratio, and glass quality.
At the eyepiece
| Target | Bresser Messier AR-102 | Sky-Watcher Evostar 100ED |
|---|---|---|
| Planets | ||
| Moon | Excellent 102mm aperture delivers sharp crater detail; some purple fringing at the bright limb from the achromatic design, reduced with a fringe-killer filter | Excellent 100mm aperture and f/9 focal ratio reward high magnification with sharp, high-contrast lunar detail |
| Saturn | Good Rings clearly separated from the disc, Cassini Division visible in steady seeing; chromatic aberration softens the image above 130× | Good 900mm focal length and clean ED optics show rings, Cassini Division in good seeing, and subtle disc banding |
| Jupiter | Good Two main equatorial belts and the four Galilean moons are easy; further belt detail limited by chromatic aberration at this focal ratio | Good 100mm resolves two or more cloud belts, GRS, and moon shadow transits; f/9 handles high power well |
| Mars | Moderate Disc and polar cap visible near opposition, but the short focal length and chromatic aberration limit surface detail | Moderate Disc visible with polar cap and large albedo features at opposition, but 100mm limits fine surface detail |
Deep sky | ||
| Orion Nebula (M42) | Excellent 102mm at f/6.5 shows the full nebula extent with bright wings and the Trapezium resolved cleanly | Good Bright nebula core and trapezium well shown, but 900mm focal length crops the outer wings |
| Andromeda Galaxy (M31) | Excellent 660mm focal length frames the bright core and inner halo in one field; 102mm aperture helps reveal dust lane hints under dark skies | Good Bright core and inner halo visible; 900mm frames only the central region, missing the full extent |
| Open clusters | Excellent Wide field and 660mm focal length are ideal — the Double Cluster, Pleiades, and M35 all fit comfortably | Good Compact clusters like M35 frame well; larger groups like the Double Cluster fill the low-power field |
| Globular clusters | Moderate M13 and M3 appear granular at the edges; core remains unresolved at 102mm | Moderate M13 and M5 appear granular at high power but the core remains unresolved at 100mm |
| Faint galaxies | Moderate Brighter Messier galaxies like M81/M82 visible as fuzzy patches; insufficient aperture for detail in fainter targets | Moderate Brighter Messier galaxies detectable as smudges; 100mm lacks the aperture for structure or faint targets |
| Milky Way / wide field | Good 660mm focal length gives wide fields at low power; slightly longer than the ideal ≤400mm for sweeping but still very effective for rich star fields | Not recommended 900mm focal length produces too narrow a field for sweeping Milky Way star fields |
Other | ||
| Double stars | Good 102mm resolves to ~1.1 arcsecond; the fast focal ratio and chromatic aberration reduce contrast on close bright pairs compared to a longer f/ratio scope | Excellent Clean ED optics at f/9 produce tight diffraction patterns; Dawes limit around 1.2 arcseconds |
The real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
Bresser Messier AR-102
- You'll unbox this and be observing the same evening — the EQ mount, tripod, finder, and eyepieces are all in the box, so your first night is spent under the stars, not shopping for accessories.
- You'll find yourself naturally drawn to low-power sweeping: the 3° true field at f/6.5 rewards you with the full spread of the Double Cluster, the wings of Orion, and lazy drifts along the Milky Way — this is where the scope feels most alive.
- You'll wince when you push past 130× on Jupiter or Saturn — the purple fringe on bright limbs is unmistakable, and you'll learn quickly that this scope wants to stay at moderate power rather than chasing fine planetary detail.
Sky-Watcher Evostar 100ED
- You'll spend your first few hundred pounds before you ever look through it — there's no mount, no diagonal, no finder, and no eyepieces in the box, so you're building a system, not buying a telescope.
- You'll be rewarded the first time you rack up to 200× on the Moon and see razor-sharp crater rims with virtually no false colour — the ED glass at f/9 delivers the kind of clean, contrasty image the Bresser simply cannot match on bright targets.
- You'll feel the 900mm focal length boxing you in when you try to frame big objects like the Andromeda Galaxy or the Veil Nebula — the narrow field is the price you pay for that crisp high-magnification performance.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Bresser
Bresser Messier AR-102
The achromatic doublet at f/6.5 produces noticeable purple fringing on bright objects above roughly 120×, and no amount of technique will fix it — it's baked into the optical design.
The equatorial mount ships without a tracking motor, so at high magnification objects drift out of the field quickly, and any form of long-exposure astrophotography is off the table without an aftermarket motor.
The tube sits near the mount's practical weight limit, so adding a camera, heavier eyepieces, or a dew shield can tip the balance into noticeable vibration and long settling times.
Sky-Watcher
Sky-Watcher Evostar 100ED
Sold as an OTA only — mount, diagonal, finder, and eyepieces must all be purchased separately, so real out-of-pocket cost to actually observe is well above the £449 sticker price.
At f/9 the focal ratio is slow for deep-sky imaging, demanding long exposures even with a quality tracking mount, and the field is too narrow for wide-field targets without adding a focal reducer.
As an ED doublet rather than a triplet, some residual chromatic aberration is still visible on very bright stars — much less than the Bresser's achromat, but not completely absent.
Which is right for you?
Two different buyers. Two different right answers.
The sky-learner's equatorial scope
Bresser · Bresser Messier AR-102
You're new to astronomy and you want one purchase that gets you outside with a real equatorial mount, a quality dual-speed focuser, and enough aperture to sweep the Milky Way and enjoy the Moon on your very first night. You're drawn to wide, low-power vistas — open clusters, big nebulae, glittering star fields — and you're happy to accept some colour fringing on planets in exchange for a complete, ready-to-use setup at a genuinely modest price. This isn't for you if crisp high-magnification planetary detail matters more than sweeping the sky, or if you have ambitions for long-exposure astrophotography.
The custom-rig optical tube
Sky-Watcher · Sky-Watcher Evostar 100ED
You already own an equatorial mount — or you're ready to invest in one — and what you really want is the sharpest, cleanest views a 100mm refractor can deliver on the Moon, planets, and tight double stars. You're willing to assemble your own accessory kit and spend significantly more than the OTA price because you value optical quality over out-of-the-box convenience. This isn't for you if you need a turnkey package, if you're on a tight total budget, or if wide-field deep-sky sweeping is more your style than high-power planetary observing.
Our verdict
This comparison has a catch: the Sky-Watcher Evostar 100ED is a bare optical tube. You cannot use it without a separate mount — which adds meaningful cost and complexity. The Bresser Messier AR-102 is a complete, ready-to-observe package.
For most buyers, the Bresser Messier AR-102 is the right choice — you can observe the same night it arrives. The Sky-Watcher Evostar 100ED makes sense if you already own a compatible mount, or are deliberately building a specific imaging setup piece by piece. If I had to choose for a first telescope: the Bresser Messier AR-102, without hesitation.
Bresser Messier AR-102
View Bresser Messier AR-102 →Sky-Watcher Evostar 100ED
View Sky-Watcher Evostar 100ED →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 AR-102 | Sky-Watcher Evostar 100ED |
|---|---|---|
Apertureⓘ The most important spec — bigger = more light = better views | 102mm | 100mm |
Focal Length Longer = more magnification potential | 660mm | 900mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/6.47 | f/9 |
Optical Design The type of optics — each design has different strengths | Refractor | Refractor |
Coatings Better coatings = more light transmission through the optics | Fully multi-coated achromatic doublet | Fully multi-coated ED doublet |
How do you point it?
| Spec | Bresser Messier AR-102 | Sky-Watcher Evostar 100ED |
|---|---|---|
Mount Type The mechanical system that holds and moves the telescope | Equatorial | None (OTA only) |
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 AR-102 | Sky-Watcher Evostar 100ED |
|---|---|---|
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 (with 1.25" adapter) |
Size & weight
| Spec | Bresser Messier AR-102 | Sky-Watcher Evostar 100ED |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 3kg | 2.6kg |
Total Weight Full setup including mount — this is what you lug to the car | 9.5kg | — |
Tube Length | 660mm | 720mm |
Tube Material | Aluminium | Aluminium |
What's in the box?
| Spec | Bresser Messier AR-102 | Sky-Watcher Evostar 100ED |
|---|---|---|
Eyepieces Included eyepieces — more is better, but quality matters more than quantity | 25mm and 10mm eyepieces | — |
Finder Scope Helps you locate areas of the sky before switching to the main eyepiece | 8x50 optical finder | — |
Diagonalⓘ Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Blue highlight: Bresser Messier AR-102 advantage · Amber highlight: Sky-Watcher Evostar 100ED advantage · Greyed cells: equal or subjective.