Telescope Comparison
Bresser Messier NT-203/800 OTA vs Sky-Watcher Virtuoso GTi 150P
The Sky-Watcher Virtuoso GTi 150P is a complete setup. The Bresser Messier NT-203/800 OTA needs a mount before it's usable.
First light
Bresser · 203mm · £329
The custom-rig optical tube
- 203mm newtonian reflector — optical tube only, no mount included
- 800mm focal length at f/3.9
- 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
Sky-Watcher · 150mm · £449
The guided beginner's telescope
- 150mm newtonian reflector on a computerised mount with motorised tracking
- Good for: Moon, planets, bright nebulae, star clusters, and deep-sky objects
- GoTo system finds any object in its database after initial star alignment — no star atlas needed
- Tracking motors keep objects centred as Earth rotates — useful above 100×, essential for photography
- 6.5kg total — requires a fixed garden spot or car transport
The full picture
The numbers that separate these two scopes — and what they mean at the eyepiece.
Aperture
Bresser Messier NT-203/800 OTA 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
Bresser Messier NT-203/800 OTA's longer focal length reaches higher magnification with the same eyepiece — better reach for planetary detail. Sky-Watcher Virtuoso GTi 150P's shorter focal length gives a wider true field — better for large open clusters and extended nebulae.
Focal ratio
Bresser Messier NT-203/800 OTA's faster f/3.9 delivers wider fields with any eyepiece — better for open clusters and large nebulae. Sky-Watcher Virtuoso GTi 150P's f/5 provides more magnification per eyepiece — better for fine planetary detail.
Mount type
Bresser Messier NT-203/800 OTA has no mount — add a compatible mount before you can observe. Sky-Watcher Virtuoso GTi 150P 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 Newtonian reflectors — the same optical formula. Any performance difference comes from collimation quality, focal ratio, and eyepiece choice, not the design itself.
At the eyepiece
Bresser
Bresser Messier NT-203/800 OTA
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 NT-203/800 OTA gathers 1.8× more light than the Sky-Watcher Virtuoso GTi 150P — 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 Virtuoso GTi 150P
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.
The Sky-Watcher Virtuoso GTi 150P is a complete package — everything arrives in one box and you can observe the same day. The Bresser Messier NT-203/800 OTA is a bare optical tube that needs a separate compatible mount before you can point it at anything, adding significant cost and complexity. Unless you already own a suitable mount, the Sky-Watcher Virtuoso GTi 150P is the practical choice.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Bresser
Bresser Messier NT-203/800 OTA
No mount included
You cannot observe until you buy a separate compatible mount — add at least £100–300 before you have a working telescope.
Nothing to look through on day one
Until a mount arrives, the optical tube is a piece of glass you cannot point at the sky.
Sky-Watcher
Sky-Watcher Virtuoso GTi 150P
Alignment required every session
GoTo star alignment cannot be skipped — the mount needs to know where it is pointing before it can find objects. This adds several minutes to the start of every session, every time.
Collimation: the skill nobody mentions in the listing
The mirrors go out of alignment with use. Stars look bloated rather than sharp when this happens. Users report that a Cheshire eyepiece makes collimation straightforward once learned, but most beginners don't discover they need it until their second or third month.
Which is right for you?
Two different buyers. Two different right answers.
The custom-rig optical tube
Bresser · Bresser Messier NT-203/800 OTA
You’ll love this if…
- You already own a compatible equatorial or alt-az mount — this is the optical tube you've specifically chosen to put on it
- You're building an imaging rig piece by piece and know exactly what you need at the end of a focuser
- Choosing an optical tube independently of the mount gives you more flexibility over your overall system
This will frustrate you if…
- You buy it without fully accounting for the mount — add at least £100–300 to the purchase price before you have a working telescope
- You expected a complete package and didn't realise this is a bare optical tube that cannot be used without a separate mount
The guided beginner's telescope
Sky-Watcher · Sky-Watcher Virtuoso GTi 150P
You’ll love this if…
- You want to navigate straight to targets without a star atlas — align once and the scope slews to any object in its database on demand
- You observe from a light-polluted garden where star-hopping to faint deep-sky objects would take most of a clear night
- You want objects to stay centred at high magnification without having to manually nudge the scope every few minutes
This will frustrate you if…
- You find the star alignment required at the start of every session frustrating — GoTo alignment cannot be skipped, and several minutes on a cold night before you can observe is the reality
- You notice that stars look bloated rather than sharp and don't know why — users report this is usually a collimation issue that's straightforward to fix once you know about it, but the listing doesn't mention it
Our verdict
This comparison has a catch: the Bresser Messier NT-203/800 OTA is a bare optical tube. You cannot use it without a separate mount — which adds meaningful cost and complexity. The Sky-Watcher Virtuoso GTi 150P is a complete, ready-to-observe package.
For most buyers, the Sky-Watcher Virtuoso GTi 150P is the right choice — you can observe the same night it arrives. The Bresser Messier NT-203/800 OTA 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 Sky-Watcher Virtuoso GTi 150P, without hesitation.
Bresser Messier NT-203/800 OTA
View Bresser Messier NT-203/800 OTA →Sky-Watcher Virtuoso GTi 150P
View Sky-Watcher Virtuoso GTi 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 NT-203/800 OTA | Sky-Watcher Virtuoso GTi 150P |
|---|---|---|
Apertureⓘ The most important spec — bigger = more light = better views | 203mm | 150mm |
Focal Length Longer = more magnification potential | 800mm | 750mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/3.9 | f/5 |
Optical Design The type of optics — each design has different strengths | Newtonian Reflector | Newtonian Reflector |
Coatings Better coatings = more light transmission through the optics | Parabolic primary mirror with aluminium coating and SiO2 overcoat | Parabolic primary mirror with multi-coated optics |
How do you point it?
| Spec | Bresser Messier NT-203/800 OTA | Sky-Watcher Virtuoso GTi 150P |
|---|---|---|
Mount Type The mechanical system that holds and moves the telescope | None (OTA only) | GoTo (Computerised) |
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 NT-203/800 OTA | Sky-Watcher Virtuoso GTi 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 | Hexafoc dual-speed Crayford | Rack and pinion |
Size & weight
| Spec | Bresser Messier NT-203/800 OTA | Sky-Watcher Virtuoso GTi 150P |
|---|---|---|
OTA Weight Optical tube only — useful for comparing mount load capacity | 6.5kg | 6.5kg |
Total Weight Full setup including mount — this is what you lug to the car | — | 6.5kg |
Tube Length | 800mm | — |
Tube Material | Carbon fibre composite | Steel (collapsible FlexTube) |
What's in the box?
| Spec | Bresser Messier NT-203/800 OTA | Sky-Watcher Virtuoso GTi 150P |
|---|---|---|
Eyepieces Included eyepieces — more is better, but quality matters more than quantity | — | 25mm and 10mm Super eyepieces |
Finder Scope Helps you locate areas of the sky before switching to the main eyepiece | — | Red dot finder |
Diagonal Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Smart features
| Spec | Bresser Messier NT-203/800 OTA | Sky-Watcher Virtuoso GTi 150P |
|---|---|---|
Built-in Camera Records and stacks images automatically — no separate camera needed | ||
App Controlled | ||
WiFi | ||
Battery Included |
Blue highlight: Bresser Messier NT-203/800 OTA advantage · Amber highlight: Sky-Watcher Virtuoso GTi 150P advantage · Greyed cells: equal or subjective.