Telescope Comparison
Bresser Messier NT-203/800 OTA vs Sky-Watcher Explorer 150PDS OTA
203mm versus 150mm — the aperture difference is the comparison.
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 · £229
The custom-rig optical tube
- 150mm newtonian reflector — optical tube only, no mount included
- 750mm focal length at f/5
- 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 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 Explorer 150PDS OTA'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 Explorer 150PDS OTA's f/5 provides more magnification per eyepiece — better for fine planetary detail.
Mount type
Neither scope includes a mount — both require a separate purchase before you can observe.
Weight (OTA)
Sky-Watcher Explorer 150PDS OTA's optical tube is 1.3kg lighter. Relevant if you plan to use it on multiple mounts or carry the tube to dark-sky sites separately.
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 Explorer 150PDS OTA — 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 150PDS 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 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 Bresser Messier NT-203/800 OTA costs 44% more. It delivers 53mm more aperture — a real and visible advantage on faint targets. For a first telescope, the Sky-Watcher Explorer 150PDS OTA is the smarter entry point. Return to the Bresser Messier NT-203/800 OTA when you know from experience what you actually need.
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 Explorer 150PDS 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.
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 custom-rig optical tube
Sky-Watcher · Sky-Watcher Explorer 150PDS 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
Our verdict
At £229 versus £329, the Bresser Messier NT-203/800 OTA costs 44% more. It delivers 53mm more aperture — a real and visible advantage on faint targets.
If budget is a genuine constraint, the Sky-Watcher Explorer 150PDS OTA will make you a happy observer. The Bresser Messier NT-203/800 OTA'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 150PDS OTA, use it for a year, then upgrade knowing exactly what you want.
Bresser Messier NT-203/800 OTA
View Bresser Messier NT-203/800 OTA →Sky-Watcher Explorer 150PDS OTA
View Sky-Watcher Explorer 150PDS OTA →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 Explorer 150PDS OTA |
|---|---|---|
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 aluminium coating and SiO2 overcoat |
How do you point it?
| Spec | Bresser Messier NT-203/800 OTA | Sky-Watcher Explorer 150PDS OTA |
|---|---|---|
Mount Type The mechanical system that holds and moves the telescope | None (OTA only) | 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 NT-203/800 OTA | Sky-Watcher Explorer 150PDS OTA |
|---|---|---|
Focuser Size 2" accepts wider eyepieces and gives better low-power views | 2" | 2" / 1.25" |
Focuser Type Rack-and-pinion is standard; Crayford and dual-speed are smoother | Hexafoc dual-speed Crayford | Dual-speed Crayford (10:1) |
Size & weight
| Spec | Bresser Messier NT-203/800 OTA | Sky-Watcher Explorer 150PDS OTA |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 6.5kg | 5.2kg |
Tube Length | 800mm | 710mm |
Tube Material | Carbon fibre composite | Aluminium |
What's in the box?
| Spec | Bresser Messier NT-203/800 OTA | Sky-Watcher Explorer 150PDS OTA |
|---|---|---|
Diagonal Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Blue highlight: Bresser Messier NT-203/800 OTA advantage · Amber highlight: Sky-Watcher Explorer 150PDS OTA advantage · Greyed cells: equal or subjective.