Maksutov-CassegrainOptical tube onlySky-Watcher
A 127 mm f/11.8 Maksutov-Cassegrain — a small, sealed, high-contrast tube that punches far above its size on the Moon, planets and double stars.
The best lunar and planetary view available from a telescope this small, bought at the cost of a very narrow field and a long cooldown.
Sold as an optical tube only. No mount, tripod or head is included. For imaging in particular, the mount is usually the larger part of the total cost.
Where to buy
Links open at the retailer in a new tab. We do not publish prices, because a price we recorded last month is worse than no price at all.
The same four purposes are scored for every telescope on this site, using the same weights. A telescope that is excellent for one is often poor for another — that is the point.
Visual observing
6.3 / 10
Confidence: high
Superb within its narrow specialism and very portable, but 127 mm and a sub-degree field limit its general deep-sky usefulness.
| Factor | Score | Weight |
|---|---|---|
| Aperture | 4.6 | 30% |
| Optical qualityeditorial | 8.0 | 20% |
| Ergonomicseditorial | 7.5 | 15% |
| Portability | 8.5 | 15% |
| Mount usabilitySold without a mount — the mount is a separate purchase and a separate decision. | 2.0 | 10% |
| Valueeditorial | 7.5 | 10% |
Weighted total: 6.3. Read the full methodology.
Nebula imaging
3.4 / 10
Confidence: high
f/11.8 is far too slow and the field far too narrow for extended nebulosity.
| Factor | Score | Weight |
|---|---|---|
| Focal ratio | 0.1 | 25% |
| Corrected field | 5.5 | 20% |
| Image circleNo image circle or sensor compatibility published — treated conservatively. | 4.0 | 15% |
| Focal length fit | 3.4 | 15% |
| Mount demand | 2.2 | 10% |
| Imaging workfloweditorial | 6.0 | 10% |
| Valueeditorial | 7.5 | 5% |
Weighted total: 3.4. Read the full methodology.
Galaxy imaging
6.8 / 10
Confidence: medium
The focal length sits in the right window but the small aperture and slow focal ratio make integration times impractical.
| Factor | Score | Weight |
|---|---|---|
| Focal length fit | 10.0 | 25% |
| Resolving power | 5.3 | 20% |
| Corrected field | 5.5 | 15% |
| Optical qualityeditorial | 8.0 | 15% |
| Mount demand | 2.2 | 10% |
| Imaging workfloweditorial | 6.0 | 10% |
| Valueeditorial | 7.5 | 5% |
Weighted total: 6.8. Read the full methodology.
Planetary imaging
6.7 / 10
Confidence: high
Long native focal length and high contrast make it a capable planetary imager; only aperture keeps it below the larger catadioptrics.
| Factor | Score | Weight |
|---|---|---|
| Aperture | 4.6 | 30% |
| Focal length fit | 8.7 | 25% |
| Optical qualityeditorial | 8.0 | 20% |
| Collimation & thermals | 6.5 | 10% |
| TrackingNo mount supplied — tracking quality depends entirely on the mount you pair it with. | 5.0 | 10% |
| Valueeditorial | 7.5 | 5% |
Weighted total: 6.7. Read the full methodology.
Scores are relative to every telescope on this site, not absolute quality marks. A 6.5 for galaxy imaging and a 6.5 for visual observing do not mean the same thing. How scoring works.
A thick meniscus corrector at the front, a spherical primary at the back, and a secondary formed by an aluminised spot on the inside of the corrector itself. Because the secondary is part of the corrector there is nothing to misalign, which is why Maksutovs effectively never need collimating.
The spot secondary is small — around 27% by diameter — and that is the source of the design’s reputation for contrast. It is also why the light cone is so slow: f/11.8 is the price of a compact tube with a long focal length.
Within its specialism this is a remarkable little telescope. Cassini’s division, festoons in Jupiter’s belts, and craterlets on the lunar floor are all within reach on a steady night. Double stars separate crisply because the diffraction pattern is clean.
Outside that specialism it is limited. The maximum true field is under a degree, so the Pleiades do not fit and large nebulae are viewed through a keyhole. Owners almost always pair it with a short refractor or binoculars rather than using it alone.
Not viable. f/11.8 means very long integration times and the field of view covers a small fraction of most nebulae.
1 500 mm is in the right focal-length range for galaxies, and that makes this telescope look plausible on paper. In practice 127 mm at f/11.8 collects so little light that exposures become impractical, and there is no reducer that fixes the aperture.
This is where the Skymax earns its place. 1 500 mm native focal length means a planetary camera needs only modest amplification to reach a good sampling ratio, the contrast is excellent, and the tube is small enough to carry outside early and let it settle. Aperture caps the ultimate resolution — an 8-inch will resolve finer detail — but per kilogram and per pound spent this is outstanding.
3.5 kg and 365 mm long: this rides comfortably on a small alt-azimuth mount and packs into a daypack. The one discipline it demands is thermal. Take it outside 45 to 90 minutes before you intend to observe seriously, and fit a dew heater on the corrector if your nights are damp.
| Aperture | 127 mm (5") |
|---|---|
| Focal length | 1500 mm (59.1") |
| Focal ratio | f/11.8 |
| Optical design | Gregory-Maksutov Cassegrain |
| Type | Maksutov-Cassegrain |
| Glass / mirror | Thick meniscus corrector with aluminised spot secondary |
| Central obstruction | 27% |
| Resolving power | 0.91"Calculated from aperture (Dawes limit), not a manufacturer figure. |
| Limiting magnitude | ≈ 12.5Estimated from aperture under dark skies. Real skies are usually worse. |
| Field correction built in | No |
|---|---|
| Usable visually | Yes |
| APS-C sensors | Not fully covered |
| Corrector required | No |
| Autoguiding | Not essential |
| Mount included | No — optical tube only |
|---|---|
| Tracking | Depends on your mount |
| GoTo | Depends on your mount |
| Mounting interface | Vixen-style dovetail |
| OTA weight | 3.5 kg (7.7 lb) |
|---|---|
| Tube length | 365 mm (14.4") |
| Tube diameter | 150 mm |
| Longest transport dimension | 420 mm (16.5") |
| Brand | Sky-Watcher |
|---|---|
| Model | Skymax 127 Maksutov-Cassegrain |
| Status | Current |
| Price band | Mid-rangeWe publish bands, not prices. Check the retailer for the current price. |
| Skill level | beginner, intermediate |
Editorial notes
We list an accessory as included only when the product record says so explicitly. If a mount, eyepiece, camera, flattener, reducer, corrector, guider or adapter is not listed above, assume it is not in the box.
Schmidt-Cassegrain
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