Telescope Comparison
Askar 80PHQ vs Vixen ED80Sf
The specs are close. The experience isn't.
First light
Askar · 80mm · £799
The custom-rig optical tube
- 80mm refractor — optical tube only, no mount included
- 448mm focal length at f/5.6
- 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
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
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
Vixen ED80Sf's longer focal length reaches higher magnification with the same eyepiece — better reach for planetary detail. Askar 80PHQ's shorter focal length gives a wider true field — better for large open clusters and extended nebulae.
Focal ratio
Askar 80PHQ's faster f/5.6 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 | Askar 80PHQ | Vixen ED80Sf |
|---|---|---|
| Planets | ||
| Moon | Excellent 80mm aperture delivers sharp lunar detail; short focal length limits magnification but crater fields and terminator are crisp | Excellent 80mm aperture with ED glass delivers sharp, colour-free crater detail; f/7.5 handles high magnification well |
| Saturn | Good Rings clearly visible at modest magnification; 448mm focal length limits high-power planetary detail | Good Rings clearly defined, Cassini Division visible in steady seeing; 600mm focal length adequate for useful magnification with a short Barlow |
| Jupiter | Good Main cloud belts and Galilean moons visible, but the short focal length constrains useful magnification | Good Main equatorial belts and GRS visible; ED glass keeps the limb clean, but 80mm limits fine belt detail |
| Mars | Challenging Small disc visible at opposition; 80mm aperture and 448mm focal length insufficient to resolve surface features reliably | Challenging Small orange disc visible at opposition; polar cap hints possible but aperture too small for surface detail |
Deep sky | ||
| Orion Nebula (M42) | Excellent Bright target framed beautifully by the wide field; f/5.6 speed and sub-600mm focal length show full nebula extent | Excellent 80mm aperture and 600mm focal length frame the full nebula with surrounding structure; trapezium resolved |
| Andromeda Galaxy (M31) | Excellent 448mm focal length captures the full extent of M31 including outer halo; 80mm aperture adequate for the bright core and dust lanes | Excellent 600mm focal length captures the full extent of the galaxy; bright core and inner dust lanes visible |
| Open clusters | Excellent Wide field at 448mm frames large clusters like the Double Cluster, Pleiades, and Hyades superbly | Excellent 600mm focal length gives wide true field — Pleiades, Double Cluster, and M35 all fit beautifully with pinpoint stars |
| Globular clusters | Moderate 80mm aperture shows bright globulars like M13 as granular but unresolved fuzzy patches | Moderate M13 and M3 appear as fuzzy concentrated balls; 80mm cannot resolve individual stars |
| Faint galaxies | Moderate 80mm aperture detects brighter Messier galaxies as smudges; insufficient light grasp for dim NGC targets visually | Moderate Brighter Messier galaxies (M81/M82, M51) visible as faint smudges; no structure detail at 80mm |
| Milky Way / wide field | Excellent 448mm focal length at f/5.6 — ideal for sweeping rich star fields and Milky Way structure | Good 600mm is slightly long for sweeping Milky Way fields but still delivers rich star clouds with a wide-field eyepiece |
Other | ||
| Double stars | Good 80mm resolves wider doubles cleanly; the fast f/5.6 focal ratio is less ideal than a long-FL refractor for tight pairs | Good Clean ED optics split Albireo easily and handle tighter pairs like Castor; Dawes limit ~1.45 arcsec |
| Astrophotography (deep sky) | Not recommended OTA only with no mount — requires a separate equatorial or GoTo mount for any deep-sky imaging; on a suitable mount this would rate Excellent | Not applicable |
| Astrophotography (planetary) | Challenging 80mm aperture and 448mm focal length undersized for planetary imaging; a Barlow helps but cannot overcome the aperture limit | Not applicable |
| Wide-field emission nebulae (imaging) | Excellent Fast f/5.6 quad APO with integrated flattener is purpose-built for targets like the Veil, North America, and Rosette Nebulae on a suitable mount | Not applicable |
The real tradeoff
Both scopes are capable. The question is which one fits the way you actually observe.
Askar 80PHQ
- You'll spend your setup time nailing back-focus spacing to exactly 55mm — get it right and you're rewarded with pinpoint stars across a full-frame sensor with zero need for an external field flattener; get it wrong and the corners will punish you with elongated stars.
- At f/5.6, your sub-exposures accumulate signal noticeably faster than the Vixen's f/7.5, which means shorter individual exposures or fewer total subs to reach the same depth — you'll feel this most acutely on narrowband work where every photon counts.
- If you ever drop an eyepiece in for a quick visual peek between imaging runs, the 448mm focal length tops out at low magnification — this scope will never give you a satisfying look at Saturn's rings, and you'll know it was never designed to.
Vixen ED80Sf
- You'll find yourself reaching for this scope on clear weeknights just to sweep the Moon and planets — the ED glass delivers genuinely clean, fringe-free views at 100–150× that make quick visual sessions feel worthwhile in a way the Askar's short focal length simply can't.
- When you do turn to imaging, you'll need to budget for a separate field flattener to keep star shapes tight across your sensor, and at f/7.5 you'll be stacking roughly 80% more exposure time than the Askar to reach the same signal-to-noise ratio on a faint nebula.
- The 1.25"-only focuser keeps your accessory options narrow — you won't be sliding in that 2" widefield eyepiece or large-format filter wheel without an aftermarket upgrade, which is a real limitation for a scope at this price point.
The dark side
Every scope has a personality. Here’s where each one gets difficult.
Askar
Askar 80PHQ
The integrated quad-element design means your flat-field performance lives or dies on hitting the correct 55mm back-focus distance — even small spacing errors introduce field curvature and corner star elongation that no amount of post-processing will fix.
Some users report the stock focuser can struggle under the weight of heavier camera and filter-wheel combinations, so you may find yourself budgeting for a focuser upgrade on top of the already mount-less £799 OTA price.
At 80mm aperture and f/5.6, faint targets like dim galaxy groups still demand long total integration times — the fast focal ratio helps per-frame, but it doesn't compensate for the limited light-gathering area compared to a 100mm+ imaging refractor.
Vixen
Vixen ED80Sf
The standard focuser is 1.25" only, which locks you out of 2" eyepieces, many camera adapters, and larger filter setups — a significant limitation for a scope positioned at premium pricing.
Without a dedicated field flattener, camera images show coma and field curvature at the sensor edges, so astrophotography use adds an accessory cost the Askar's built-in quad-element design avoids entirely.
At £649 for an 80mm OTA with no mount, diagonal, finder, or eyepieces included, you're paying for Vixen's build precision and ED glass — not for aperture, and the total system cost to make this scope usable can rival much larger instruments.
Which is right for you?
Two different buyers. Two different right answers.
The custom-rig optical tube
Askar · Askar 80PHQ
You already own an equatorial mount with autoguiding and you want a compact, dedicated imaging OTA that delivers flat-field performance out of the box without fussing with external correctors. You're building widefield deep-sky or narrowband mosaics and you want the fastest possible focal ratio in a portable 80mm package. You accept that this scope will never be your visual telescope — you won't even unbox a diagonal for it — and you're comfortable spending the time to dial in precise back-focus spacing because you know the corner stars in your images depend on it. This isn't for you if you want any visual versatility, if you're new to astrophotography and don't yet own a tracking mount, or if you expect 80mm of aperture to compete with larger refractors on faint targets.
The custom-rig optical tube
Vixen · Vixen ED80Sf
You want one well-built refractor that does double duty — clean, colour-free visual observing of the Moon and planets on weeknights, and respectable deep-sky imaging when you pair it with a mount and field flattener on weekends. You value Vixen's mechanical precision and you're willing to pay a premium for an 80mm scope that feels like a quality instrument every time you handle it. You'll get genuine enjoyment from visual sessions in a way the imaging-only Askar can't deliver. This isn't for you if astrophotography is your sole priority — the slower f/7.5 speed, the need for an external flattener, and the 1.25"-only focuser all add friction and cost that the Askar sidesteps by design.
Our verdict
Same aperture, same light-gathering, £150 price difference. The extra cost of the Askar 80PHQ buys a different mount — not better optics.
For most beginners, the Vixen ED80Sf is the right starting point — the optics are identical and the savings are better spent on a quality eyepiece or a dark-sky trip. The Askar 80PHQ makes sense if the mount it comes with is specifically what you want to learn. If I had to choose: the Vixen ED80Sf — same sky, less money.
Askar 80PHQ
View Askar 80PHQ →Vixen ED80Sf
View Vixen ED80Sf →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 | Askar 80PHQ | Vixen ED80Sf |
|---|---|---|
Aperture The most important spec — bigger = more light = better views | 80mm | 80mm |
Focal Length Longer = more magnification potential | 448mm | 600mm |
Focal Ratio Lower f-number = wider field of view; higher = more magnification per eyepiece | f/5.6 | f/7.5 |
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 PHQ quadruplet on all surfaces | Fully multi-coated ED doublet on all air-to-glass surfaces |
How do you point it?
| Spec | Askar 80PHQ | Vixen ED80Sf |
|---|---|---|
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 | Askar 80PHQ | Vixen ED80Sf |
|---|---|---|
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 2" (with 1.25" adapter) | Dual-speed Crayford (with 1.25" adapter) |
Size & weight
| Spec | Askar 80PHQ | Vixen ED80Sf |
|---|---|---|
OTA Weightⓘ Optical tube only — useful for comparing mount load capacity | 2.8kg | 1.8kg |
Tube Length | 360mm | 528mm |
Tube Material | Aluminium | Aluminium |
What's in the box?
| Spec | Askar 80PHQ | Vixen ED80Sf |
|---|---|---|
Diagonal Tilts the eyepiece 90° for comfortable viewing — useful on refractors |
Blue highlight: Askar 80PHQ advantage · Amber highlight: Vixen ED80Sf advantage · Greyed cells: equal or subjective.