Telescope Comparison
Sky-Watcher Explorer 150PDS OTA vs Sky-Watcher Star Discovery 150P
The Sky-Watcher Star Discovery 150P is a complete setup. The Sky-Watcher Explorer 150PDS OTA needs a mount before it's usable.
First light
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
Sky-Watcher · 150mm · £429
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
- 9.5kg 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
Equal light-gathering. Aperture won't settle this comparison — the mount, focal ratio, and observing experience are what differ.
Focal length
Same focal length — identical magnification with any given eyepiece. Differences come from optical design and coatings.
Focal ratio
Same focal ratio — the same eyepiece gives equivalent magnification and true field in both scopes.
Mount type
Sky-Watcher Explorer 150PDS OTA has no mount — add a compatible mount before you can observe. Sky-Watcher Star Discovery 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
Both scopes · same aperture
Both are 150mm Newtonian reflectors — light gathering is identical. What you see through each depends on your eyepieces, your sky, and the steadiness of the atmosphere, not which scope you bought. Saturn's rings separate clearly from the disk; in good seeing, the Cassini Division — the dark gap between the A and B rings — is a genuine target at moderate magnification. Jupiter shows two equatorial cloud bands reliably, four Galilean moons changing position night to night. The Orion Nebula (M42) shows real nebulosity around the Trapezium, which splits into four stars at moderate magnification. The Andromeda Galaxy (M31) fills a wide-field eyepiece, the bright core distinct from the outer halo. What separates these scopes is the mount, the setup experience, and where you can use them — not what you see through them.
The real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
The Sky-Watcher Star Discovery 150P is a complete package — everything arrives in one box and you can observe the same day. The Sky-Watcher Explorer 150PDS 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 Star Discovery 150P is the practical choice.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
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.
Sky-Watcher
Sky-Watcher Star Discovery 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
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
The guided beginner's telescope
Sky-Watcher · Sky-Watcher Star Discovery 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 Sky-Watcher Explorer 150PDS OTA is a bare optical tube. You cannot use it without a separate mount — which adds meaningful cost and complexity. The Sky-Watcher Star Discovery 150P is a complete, ready-to-observe package.
For most buyers, the Sky-Watcher Star Discovery 150P is the right choice — you can observe the same night it arrives. The Sky-Watcher Explorer 150PDS 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 Star Discovery 150P, without hesitation.
Sky-Watcher Explorer 150PDS OTA
View Sky-Watcher Explorer 150PDS OTA →Sky-Watcher Star Discovery 150P
View Sky-Watcher Star Discovery 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 | Sky-Watcher Explorer 150PDS OTA | Sky-Watcher Star Discovery 150P |
|---|---|---|
Aperture The most important spec — bigger = more light = better views | 150mm | 150mm |
Focal Length Longer = more magnification potential | 750mm | 750mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/5 | 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 | Sky-Watcher Explorer 150PDS OTA | Sky-Watcher Star Discovery 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 | Sky-Watcher Explorer 150PDS OTA | Sky-Watcher Star Discovery 150P |
|---|---|---|
Focuser Size 2" accepts wider eyepieces and gives better low-power views | 2" / 1.25" | 2" |
Focuser Type Rack-and-pinion is standard; Crayford and dual-speed are smoother | Dual-speed Crayford (10:1) | Rack and pinion |
Size & weight
| Spec | Sky-Watcher Explorer 150PDS OTA | Sky-Watcher Star Discovery 150P |
|---|---|---|
OTA Weight Optical tube only — useful for comparing mount load capacity | 5.2kg | 5.2kg |
Total Weight Full setup including mount — this is what you lug to the car | — | 9.5kg |
Tube Length | 710mm | 710mm |
Tube Material | Aluminium | Aluminium |
What's in the box?
| Spec | Sky-Watcher Explorer 150PDS OTA | Sky-Watcher Star Discovery 150P |
|---|---|---|
Eyepieces Included eyepieces — more is better, but quality matters more than quantity | — | 10mm and 25mm 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 | Sky-Watcher Explorer 150PDS OTA | Sky-Watcher Star Discovery 150P |
|---|---|---|
Built-in Camera Records and stacks images automatically — no separate camera needed | ||
App Controlled | ||
WiFi | ||
Battery Included |
Blue highlight: Sky-Watcher Explorer 150PDS OTA advantage · Amber highlight: Sky-Watcher Star Discovery 150P advantage · Greyed cells: equal or subjective.