Telescope Comparison
Celestron CGEM II 8 SCT vs Celestron NexStar Evolution 9.25
The specs are close. The experience isn't.
First light
Celestron · 203mm · £2,199
The automated deep-sky platform
- 203mm schmidt-cassegrain 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
- 34kg total — requires a fixed garden spot or car transport
Celestron · 235mm · £2,499
The automated deep-sky platform
- 235mm schmidt-cassegrain 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
- 21kg 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
Celestron NexStar Evolution 9.25 gathers 1.3× 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
Celestron NexStar Evolution 9.25's longer focal length reaches higher magnification with the same eyepiece — better reach for planetary detail. Celestron CGEM II 8 SCT's shorter focal length gives a wider true field — better for large open clusters and extended nebulae.
Focal ratio
Same focal ratio — the same eyepiece gives equivalent magnification and true field in both scopes.
Mount type
Same mount type — setup experience and ergonomics will be similar. Differences lie in build quality and included accessories.
Weight (OTA)
Celestron CGEM II 8 SCT's optical tube is 2.3kg lighter. Relevant if you plan to use it on multiple mounts or carry the tube to dark-sky sites separately.
Optical design
Both Schmidt-Cassegrain designs — versatile, compact, good for planets and deep-sky. Differences come from aperture and mount.
At the eyepiece
Celestron
Celestron CGEM II 8 SCT
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.
Celestron
Celestron NexStar Evolution 9.25
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 real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
Both scopes are solving a similar problem in a similar way. The differences are real — build quality and optical refinement — but these show up after several months of regular use, not on the first night. Pick the one whose design best matches how you actually plan to observe.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Celestron
Celestron CGEM II 8 SCT
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.
Not a spontaneous telescope
At 34kg total, this goes out when you plan to go out — not for a quick look on a clear evening.
Celestron
Celestron NexStar Evolution 9.25
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.
Not a spontaneous telescope
At 21kg total, this goes out when you plan to go out — not for a quick look on a clear evening.
Which is right for you?
Two different buyers. Two different right answers.
The automated deep-sky platform
Celestron · Celestron CGEM II 8 SCT
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
- Astrophotography is where you're headed — the tracking equatorial mount is the essential first component of any imaging setup
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 want to take it out for spontaneous sessions — at this weight, getting it in and out of a car on your own requires planning and ideally a second pair of hands
The automated deep-sky platform
Celestron · Celestron NexStar Evolution 9.25
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 want to take it out for spontaneous sessions — at this weight, getting it in and out of a car on your own requires planning and ideally a second pair of hands
Our verdict
These two are closer than most comparisons on this site. The spec differences are genuine — mount type, focal ratio — but neither is the wrong answer for a typical observer starting out.
If I had to choose between them: the Celestron CGEM II 8 SCT is the scope most people will be using regularly six months from now. The Celestron NexStar Evolution 9.25 rewards you more once you know what you're doing — it's worth revisiting after your first year.
Celestron CGEM II 8 SCT
View Celestron CGEM II 8 SCT →Celestron NexStar Evolution 9.25
View Celestron NexStar Evolution 9.25 →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 | Celestron CGEM II 8 SCT | Celestron NexStar Evolution 9.25 |
|---|---|---|
Apertureⓘ The most important spec — bigger = more light = better views | 203mm | 235mm |
Focal Length Longer = more magnification potential | 2032mm | 2350mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/10 | f/10 |
Optical Design The type of optics — each design has different strengths | Schmidt-Cassegrain | Schmidt-Cassegrain |
Coatings Better coatings = more light transmission through the optics | StarBright XLT multi-layer coatings | StarBright XLT fully multi-coated on all optical surfaces |
How do you point it?
| Spec | Celestron CGEM II 8 SCT | Celestron NexStar Evolution 9.25 |
|---|---|---|
Mount Type The mechanical system that holds and moves the telescope | GoTo (Computerised) | 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 | Celestron CGEM II 8 SCT | Celestron NexStar Evolution 9.25 |
|---|---|---|
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 | SCT rear-cell focuser with reducer thread | SCT rear-cell focuser |
Size & weight
| Spec | Celestron CGEM II 8 SCT | Celestron NexStar Evolution 9.25 |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 5.4kg | 7.7kg |
Total Weightⓘ Full setup including mount — this is what you lug to the car | 34kg | 21kg |
Tube Length | 432mm | 508mm |
Tube Material | Aluminium | Aluminium |
What's in the box?
| Spec | Celestron CGEM II 8 SCT | Celestron NexStar Evolution 9.25 |
|---|---|---|
Eyepieces Included eyepieces — more is better, but quality matters more than quantity | 40mm eyepiece | 25mm Plössl |
Finder Scope Helps you locate areas of the sky before switching to the main eyepiece | 8x50 right-angle finder scope | StarPointer red dot finder |
Diagonalⓘ Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Smart features
| Spec | Celestron CGEM II 8 SCT | Celestron NexStar Evolution 9.25 |
|---|---|---|
Built-in Camera Records and stacks images automatically — no separate camera needed | ||
App Controlled | ||
WiFi | ||
Battery Included |
Blue highlight: Celestron CGEM II 8 SCT advantage · Amber highlight: Celestron NexStar Evolution 9.25 advantage · Greyed cells: equal or subjective.