Telescope Comparison
Celestron AstroMaster 102AZ vs Explore Scientific AR102
The Celestron AstroMaster 102AZ is a complete setup. The Explore Scientific AR102 needs a mount before it's usable.
First light
Celestron · 102mm · £189
The simple alt-az visual scope
- 102mm refractor on a simple alt-az mount
- Good for: Moon, planets, bright open clusters
- No alignment required — quick to set up, intuitive to move
- Finding objects requires learning to star-hop: navigate with a finder scope and sky chart
- 6.4kg total — manageable to carry to dark-sky sites
Explore Scientific · 102mm · £149
The custom-rig optical tube
- 102mm refractor — optical tube only, no mount included
- 660mm focal length at f/6.5
- 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
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
Explore Scientific AR102 has no mount — add a compatible mount before you can observe. Celestron AstroMaster 102AZ 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
Both scopes · same aperture
Both refractors share essentially the same aperture — views through each will be very similar on all standard targets. The hallmarks of good refractor optics are sharp stars and good contrast on planetary targets, with no false colour on ED or apochromatic glass. Saturn's rings are distinct from the disk; Jupiter shows two equatorial bands. The Orion Nebula (M42) is bright and well-defined. Open clusters are a strength — the Double Cluster in Perseus and the Pleiades look good at low power. The differences between these two scopes show up in focal ratio, focal length, and what they're optimised for, not in fundamental light-gathering capability.
The real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
The Celestron AstroMaster 102AZ is a complete package — everything arrives in one box and you can observe the same day. The Explore Scientific AR102 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 Celestron AstroMaster 102AZ is the practical choice.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Celestron
Celestron AstroMaster 102AZ
Finding faint objects from a light-polluted garden is genuinely hard
Star-hopping to a globular cluster or dim galaxy from a suburban sky requires learning. Users report a real demoralising phase in the first weeks — landing on the wrong star field, convincing yourself it's the target, then finding out later it wasn't. This improves rapidly with experience.
Explore Scientific
Explore Scientific AR102
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 simple alt-az visual scope
Celestron · Celestron AstroMaster 102AZ
You’ll love this if…
- You want the fastest possible setup — no alignment, no polar alignment, just point and look
- Learning the sky by star-hopping feels like part of the appeal, not a barrier to it
- Portability matters — this mount is manageable to carry to a dark-sky site without a car full of equipment
This will frustrate you if…
- You try to find faint objects from a light-polluted garden and mostly fail — users report a real demoralising phase in the first weeks of star-hopping that improves quickly but is genuinely discouraging at the start
The custom-rig optical tube
Explore Scientific · Explore Scientific AR102
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
This comparison has a catch: the Explore Scientific AR102 is a bare optical tube. You cannot use it without a separate mount — which adds meaningful cost and complexity. The Celestron AstroMaster 102AZ is a complete, ready-to-observe package.
For most buyers, the Celestron AstroMaster 102AZ is the right choice — you can observe the same night it arrives. The Explore Scientific AR102 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 Celestron AstroMaster 102AZ, without hesitation.
Celestron AstroMaster 102AZ
View Celestron AstroMaster 102AZ →Explore Scientific AR102
View Explore Scientific AR102 →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 AstroMaster 102AZ | Explore Scientific AR102 |
|---|---|---|
Aperture The most important spec — bigger = more light = better views | 102mm | 102mm |
Focal Length Longer = more magnification potential | 660mm | 660mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/6.5 | f/6.5 |
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 achromatic doublet |
How do you point it?
| Spec | Celestron AstroMaster 102AZ | Explore Scientific AR102 |
|---|---|---|
Mount Type The mechanical system that holds and moves the telescope | Alt-Az | 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 | Celestron AstroMaster 102AZ | Explore Scientific AR102 |
|---|---|---|
Focuser Size 2" accepts wider eyepieces and gives better low-power views | 1.25" | 2" |
Focuser Type Rack-and-pinion is standard; Crayford and dual-speed are smoother | Rack and pinion | Crayford dual-speed |
Size & weight
| Spec | Celestron AstroMaster 102AZ | Explore Scientific AR102 |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 2.9kg | 2.8kg |
Total Weight Full setup including mount — this is what you lug to the car | 6.4kg | — |
Tube Length | 700mm | 540mm |
Tube Material | Aluminium | Aluminium |
What's in the box?
| Spec | Celestron AstroMaster 102AZ | Explore Scientific AR102 |
|---|---|---|
Eyepieces Included eyepieces — more is better, but quality matters more than quantity | 20mm and 10mm eyepieces | 26mm and 6.7mm LER eyepieces |
Finder Scope Helps you locate areas of the sky before switching to the main eyepiece | StarPointer red dot finder | 8x50 right-angle finderscope |
Diagonal Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Blue highlight: Celestron AstroMaster 102AZ advantage · Amber highlight: Explore Scientific AR102 advantage · Greyed cells: equal or subjective.