Telescope Comparison
Vixen ED80Sf vs William Optics Zenithstar 61
The specs are close. The experience isn't.
First light
Vixen · 80mm · £649
The custom-rig optical tube
- 80mm refractor — optical tube only, no mount included
- 600mm focal length at f/7.5
- 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
William Optics · 61mm · £499
The custom-rig optical tube
- 61mm refractor — optical tube only, no mount included
- 360mm focal length at f/5.9
- 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
The full picture
The numbers that separate these two scopes — and what they mean at the eyepiece.
Aperture
Vixen ED80Sf gathers 1.7× 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
Vixen ED80Sf's longer focal length reaches higher magnification with the same eyepiece — better reach for planetary detail. William Optics Zenithstar 61's shorter focal length gives a wider true field — better for large open clusters and extended nebulae.
Focal ratio
William Optics Zenithstar 61's faster f/5.9 delivers wider fields with any eyepiece — better for open clusters and large nebulae. Vixen ED80Sf's f/7.5 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)
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
| Target | Vixen ED80Sf | William Optics Zenithstar 61 |
|---|---|---|
| Planets | ||
| Moon | Excellent 80mm aperture with ED glass delivers sharp, colour-free crater detail; f/7.5 handles high magnification well | Moderate 61mm aperture shows craters and maria, but the short 360mm focal length limits useful magnification for fine detail |
| Saturn | Good Rings clearly defined, Cassini Division visible in steady seeing; 600mm focal length adequate for useful magnification with a short Barlow | Challenging Rings visible as distinct structure, but 61mm aperture and 360mm focal length cannot reveal Cassini Division or banding |
| Jupiter | Good Main equatorial belts and GRS visible; ED glass keeps the limb clean, but 80mm limits fine belt detail | Challenging Disc and two main equatorial belts visible, but small aperture limits cloud detail and the short focal length keeps the image very small |
| Mars | Challenging Small orange disc visible at opposition; polar cap hints possible but aperture too small for surface detail | Not recommended Tiny orange disc at opposition; 61mm aperture and 360mm focal length cannot resolve surface features |
Deep sky | ||
| Orion Nebula (M42) | Excellent 80mm aperture and 600mm focal length frame the full nebula with surrounding structure; trapezium resolved | Good Wide field frames the full nebula and surrounding region; 61mm shows the bright core and inner nebulosity but lacks aperture for fainter outer structure visually |
| Andromeda Galaxy (M31) | Excellent 600mm focal length captures the full extent of the galaxy; bright core and inner dust lanes visible | Excellent 360mm focal length captures the full extent of M31 and companion galaxies in a single field — ideal framing for imaging |
| Open clusters | Excellent 600mm focal length gives wide true field — Pleiades, Double Cluster, and M35 all fit beautifully with pinpoint stars | Excellent 360mm focal length gives wide true field, perfectly suited for large clusters like the Double Cluster, Pleiades, and Hyades |
| Globular clusters | Moderate M13 and M3 appear as fuzzy concentrated balls; 80mm cannot resolve individual stars | Challenging 61mm aperture shows fuzzy patches only; no star resolution possible even at the edges |
| Faint galaxies | Moderate Brighter Messier galaxies (M81/M82, M51) visible as faint smudges; no structure detail at 80mm | Not recommended 61mm aperture gathers too little light to reveal faint galaxy detail visually |
| Milky Way / wide field | Good 600mm is slightly long for sweeping Milky Way fields but still delivers rich star clouds with a wide-field eyepiece | Excellent 360mm focal length at f/5.9 delivers sweeping star fields — one of this scope's strengths both visually and for imaging |
Other | ||
| Double stars | Good Clean ED optics split Albireo easily and handle tighter pairs like Castor; Dawes limit ~1.45 arcsec | Moderate Dawes limit of ~1.9 arcseconds; wide pairs split cleanly but close doubles are beyond reach, and short focal length makes high-power splitting impractical |
| Astrophotography (deep sky) | Not applicable | Not recommended No mount or tracking included; on a suitable equatorial mount this would rate Excellent — f/5.9, APO glass, and 360mm focal length are ideal for wide-field imaging |
| Astrophotography (planetary) | Not applicable | Challenging 61mm aperture and 360mm focal length produce a very small planetary image scale; no tracking included |
| Large emission nebulae (imaging) | Not applicable | Excellent With a tracking mount, the wide f/5.9 field frames targets like the North America Nebula, Veil Nebula, and Heart/Soul complex superbly |
The real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
Vixen ED80Sf
- You'll spend your observing sessions doing genuine visual astronomy — the ED80Sf rewards you with crisp lunar rilles, Saturn's Cassini Division, and open clusters rendered as tight star fields all the way to the edge.
- When you mount this on an equatorial tracker, you get a capable wide-field imaging platform that handles large nebulae and Andromeda's full extent with well-corrected star shapes across your sensor.
- You're paying premium prices for 80mm of aperture, but you're getting optically clean views across visual, wide-field imaging, and grab-and-go portability — no single thing it does best, but nothing it does poorly.
William Optics Zenithstar 61
- You'll point this at the sky and immediately feel the limitation — the 61mm aperture and 360mm focal length mean the Moon shows craters clearly but Saturn and Jupiter remain pale discs, and planetary detail stays out of reach no matter how much patience you have.
- The moment you attach a camera and tracking mount, this telescope transforms into what it was designed to be: a wide-field imaging engine that frames the full Orion Nebula, the complete Andromeda Galaxy, and sprawling hydrogen-alpha regions as a single exposure.
- You're not buying a visual telescope that happens to image well — you're buying an imaging telescope that can show you the Moon and bright planets as a bonus, and accepting that limitation is the price of its exceptional field and portability.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Vixen
Vixen ED80Sf
Sold as OTA only with no mount, diagonal, finder, or eyepieces — your actual cost to first light is roughly £1,200–1,500 once you add these essentials.
80mm aperture cannot resolve globular cluster cores, reveal faint galaxy structure, or show meaningful Mars detail, leaving you visually outperformed by 100mm+ instruments at the same total price.
1.25″ focuser on the standard model restricts your eyepiece options and accessory compatibility compared to 2″ focuser refractors at this price point.
Field curvature and coma at the edges of camera sensors require a dedicated field flattener to achieve tack-sharp stars across full APS-C sensors, adding cost and complexity.
William Optics
William Optics Zenithstar 61
Sold as OTA only with no mount, diagonal, or eyepiece — you cannot observe with this telescope until you've invested another £400–800 in a mount and optical accessories.
61mm aperture makes this unsuitable as a primary visual telescope; Saturn, Jupiter, and the Moon show only basic structure, and deep-sky visual observing is severely limited.
Maximum useful magnification is around 120×, constraining lunar and planetary detail to basic surface features and ring systems only.
Field curvature is significant at the edges of APS-C and full-frame sensors without the Flat6A field flattener (roughly £250), making that accessory nearly essential rather than optional for clean imaging.
Which is right for you?
Two different buyers. Two different right answers.
The custom-rig optical tube
Vixen · Vixen ED80Sf
You'll love the ED80Sf if you want a single optical tube that does visual observation genuinely well — sharp lunar detail, planetary viewing, open cluster sweeping — while maintaining the flexibility to image wide-field nebulae and clusters when you mount it on a tracker. You're comfortable spending £1,200–1,500 for a complete system and you value optical cleanliness (no chromatic aberration) across multiple use cases. You're not chasing deep-sky aperture or expecting a ready-to-use package; you're an intermediate observer who knows what you need and won't compromise on build quality.
The custom-rig optical tube
William Optics · William Optics Zenithstar 61
You'll love the Zenithstar 61 if you are primarily an astrophotographer who images wide-field nebulae, Milky Way regions, and large objects that benefit from enormous true field of view — and you're willing to accept that this telescope's visual performance is secondary. You travel with your imaging rig, need portability over aperture, and can pair it with a modest equatorial mount and a dedicated astronomy camera. You're not buying this for visual observing; if you are, stop here and choose something else. Accepting the 61mm aperture limitation is the deal that unlocks what this scope does exceptionally well.
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 Vixen ED80Sf is the scope most people will be using regularly six months from now. The William Optics Zenithstar 61 rewards you more once you know what you're doing — it's worth revisiting after your first year.
Vixen ED80Sf
View Vixen ED80Sf →William Optics Zenithstar 61
View William Optics Zenithstar 61 →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 | Vixen ED80Sf | William Optics Zenithstar 61 |
|---|---|---|
Apertureⓘ The most important spec — bigger = more light = better views | 80mm | 61mm |
Focal Length Longer = more magnification potential | 600mm | 360mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/7.5 | f/5.9 |
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 ED doublet on all air-to-glass surfaces | Fully multi-coated FMC on all air-to-glass surfaces, including ED element |
How do you point it?
| Spec | Vixen ED80Sf | William Optics Zenithstar 61 |
|---|---|---|
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 | Vixen ED80Sf | William Optics Zenithstar 61 |
|---|---|---|
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 | Dual-speed Crayford (with 1.25" adapter) | Dual-speed Crayford 2" (10:1 reduction fine focus) |
Size & weight
| Spec | Vixen ED80Sf | William Optics Zenithstar 61 |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 1.8kg | 1.35kg |
Tube Length | 528mm | 270mm |
Tube Material | Aluminium | Aluminium, anodised red |
What's in the box?
| Spec | Vixen ED80Sf | William Optics Zenithstar 61 |
|---|---|---|
Diagonal Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Blue highlight: Vixen ED80Sf advantage · Amber highlight: William Optics Zenithstar 61 advantage · Greyed cells: equal or subjective.