Telescope Comparison
Explore Scientific 8" Dobsonian vs Orion StarBlast 6 Astro Reflector
203mm versus 150mm — the aperture difference is the comparison.
First light
Explore Scientific · 203mm · £299
The maximum-aperture visual reflector
- 203mm Newtonian on a floor-standing Dobsonian alt-az rocker box
- Good for: full visual programme — planets, Moon, globular clusters, galaxies, nebulae
- No alignment required — set up and observe in under 10 minutes
- No motorised tracking — targets drift at high magnification as Earth rotates
- 20kg total — designed for a fixed garden or regular dark-sky site, not casual transport
Orion · 150mm
The simple alt-az visual scope
- 150mm newtonian reflector 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
- 5.4kg total — manageable to carry to dark-sky sites
The full picture
The numbers that separate these two scopes — and what they mean at the eyepiece.
Aperture
Explore Scientific 8" Dobsonian 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
Explore Scientific 8" Dobsonian's longer focal length reaches higher magnification with the same eyepiece — better reach for planetary detail. Orion StarBlast 6 Astro Reflector's shorter focal length gives a wider true field — better for large open clusters and extended nebulae.
Focal ratio
Orion StarBlast 6 Astro Reflector's faster f/5 delivers wider fields with any eyepiece — better for open clusters and large nebulae. Explore Scientific 8" Dobsonian's f/5.9 provides more magnification per eyepiece — better for fine planetary detail.
Mount type
Both are alt-az in principle, but the Dobsonian rocker-box is typically more stable at the eyepiece. Neither scope tracks — objects drift at high magnification.
Weight (OTA)
Orion StarBlast 6 Astro Reflector's optical tube is 8.6kg lighter. Relevant if you plan to use it on multiple mounts or carry the tube to dark-sky sites separately.
Optical design
Explore Scientific 8" Dobsonian is a DOBSONIAN; Orion StarBlast 6 Astro Reflector is a Newtonian reflector (mirrors, needs occasional collimation). Different optical formulas produce different strengths — reflectors give more aperture per pound; refractors give sharper contrast and require no collimation.
At the eyepiece
Explore Scientific
Explore Scientific 8" Dobsonian
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 Explore Scientific 8" Dobsonian gathers 1.8× more light than the Orion StarBlast 6 Astro Reflector — 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.
Orion
Orion StarBlast 6 Astro Reflector
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.
Both scopes are solving a similar problem in a similar way. The differences are real — mount type and setup experience — 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.
Explore Scientific
Explore Scientific 8" Dobsonian
Objects drift out of view at high magnification
There is no tracking. At high magnification, targets drift across the field as Earth rotates and require regular manual nudging to keep them centred.
Too large for spontaneous outings
At 20kg total, getting this scope to a dark-sky site requires planning and ideally a second pair of hands. It suits a fixed garden setup or a dedicated trip, not an impulsive clear-night dash.
Orion
Orion StarBlast 6 Astro Reflector
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.
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.
Which is right for you?
Two different buyers. Two different right answers.
The maximum-aperture visual reflector
Explore Scientific · Explore Scientific 8" Dobsonian
You’ll love this if…
- More aperture per pound is your main criterion — this design gives more light-gathering for your money than any other mount type at this price
- You plan to observe from a fixed garden or regular dark-sky site where you can set it up and leave it between sessions
- You prefer manual navigation — the Dobsonian rewards patient, hands-on observing and builds genuine sky knowledge over time
This will frustrate you if…
- You want to observe at high magnification without nudging the scope constantly — there is no tracking, and targets drift across the field as Earth rotates
- You want to take it to different locations easily — at this weight and size, it's a significant lift and benefits from a second pair of hands
- 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 simple alt-az visual scope
Orion · Orion StarBlast 6 Astro Reflector
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 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
- 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
Our verdict
At similar price points, these scopes offer different amounts of aperture per pound. The Orion StarBlast 6 Astro Reflector gives you more light-gathering for your money — and for visual observing, aperture per pound is the most useful single metric.
For pure optical value, the Orion StarBlast 6 Astro Reflector is the stronger pick. The Explore Scientific 8" Dobsonian compensates with other features — decide whether those trade-offs justify the premium. If I had to choose: the Orion StarBlast 6 Astro Reflector — more aperture per pound means more sky.
Explore Scientific 8" Dobsonian
View Explore Scientific 8" Dobsonian →Orion StarBlast 6 Astro Reflector
View Orion StarBlast 6 Astro Reflector →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 | Explore Scientific 8" Dobsonian | Orion StarBlast 6 Astro Reflector |
|---|---|---|
Apertureⓘ The most important spec — bigger = more light = better views | 203mm | 150mm |
Focal Length Longer = more magnification potential | 1200mm | 750mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/5.9 | f/5 |
Optical Design The type of optics — each design has different strengths | Dobsonian | Newtonian Reflector |
Coatings Better coatings = more light transmission through the optics | Enhanced aluminium mirror coatings | 94% reflectivity parabolic primary mirror |
How do you point it?
| Spec | Explore Scientific 8" Dobsonian | Orion StarBlast 6 Astro Reflector |
|---|---|---|
Mount Type The mechanical system that holds and moves the telescope | Dobsonian | Alt-Az |
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 | Explore Scientific 8" Dobsonian | Orion StarBlast 6 Astro Reflector |
|---|---|---|
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 | Crayford | Rack and pinion |
Size & weight
| Spec | Explore Scientific 8" Dobsonian | Orion StarBlast 6 Astro Reflector |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 14kg | 5.4kg |
Total Weightⓘ Full setup including mount — this is what you lug to the car | 20kg | 5.4kg |
Tube Length | 1168mm | 635mm |
Tube Material | Steel | Steel |
What's in the box?
| Spec | Explore Scientific 8" Dobsonian | Orion StarBlast 6 Astro Reflector |
|---|---|---|
Eyepieces Included eyepieces — more is better, but quality matters more than quantity | 25mm and 10mm eyepieces | 25mm and 10mm Sirius Plössl |
Finder Scope Helps you locate areas of the sky before switching to the main eyepiece | 8x50 right-angle finderscope | EZ Finder II red dot |
Diagonal Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Blue highlight: Explore Scientific 8" Dobsonian advantage · Amber highlight: Orion StarBlast 6 Astro Reflector advantage · Greyed cells: equal or subjective.