StellaLyra · 10-inch f/12 M-LRC Classical Cassegrain
Build a dedicated setup for close-up lunar and planetary work.
The StellaLyra 10-inch carbon-truss Classical Cassegrain combines a 250mm aperture with a 3045mm focal length and nominal f/12 focal ratio. It is a substantial optical tube for observers and imagers who want to concentrate on smaller targets and fine detail.
Choose it as part of a complete system. A suitable mount, carefully selected rear accessories and a practical installation plan are central to enjoying a telescope of this size.
Make three metres of focal length a deliberate choice.
A long focal length gives a target more space on the same camera sensor and higher magnification with the same eyepiece. That is useful for a close study of lunar terrain, planets or double stars, while a larger subject may need a different framing strategy.
Start with the targets you actually want to observe or record. For imaging, check their size against your camera’s field of view. For visual use, plan a useful range of eyepieces and the tracking needed to keep a subject comfortably in view.
Extra image scale only helps when seeing, focus and tracking support it. On an unsteady night, a smaller, sharper image can reveal more than a highly magnified blur.
An open carbon-truss structure.
The carbon-fibre truss connects the optical assemblies, with Losmandy-style mounting rails above and below.
Plan protection for the exposed structure during storage and transport. Assess nearby lights and your observing environment when deciding whether additional light control is needed. Any accessory fitted around the open frame must remain clear of the optical path and moving equipment.
Carbon construction does not remove the need to check focus as conditions change. Allow the complete telescope to settle outdoors before judging its best performance.
Plan the working load and handling together.
Published tube weight is 17.2kg. Add the diagonal, eyepiece or camera, guiding equipment and other attached accessories when assessing mount suitability.
Check saddle compatibility, counterweight requirements and balance range before installation. Decide how the telescope will be supported while it is secured or removed, and whether a permanent setup would better suit your routine than repeated transport.
Balance with the actual rear equipment attached. Check that the focuser, accessories and cables remain clear of the mount, tripod or pier throughout the intended pointing range.
Fine focusing with the primary held fixed.
The 3.25-inch dual-speed linear-bearing Crayford focuser provides coarse and fine manual control while the primary mirror stays fixed.
Support the camera or diagonal during attachment, secure every connection and keep cable weight off the focuser. Assess the complete accessory train at different pointing angles. The focuser’s diameter alone does not specify an acceptable camera payload.
If you intend to automate focus, confirm the motor, bracket and coupling for the supplied focuser before buying. Record a useful starting focus position, then refine it on the target rather than assuming yesterday’s setting will be exact.
Practical eyepiece examples.
Magnification is the telescope’s focal length divided by the eyepiece focal length. At the native focal length:
| Eyepiece focal length | Approximate magnification |
|---|---|
| 30mm | 102× |
| 20mm | 152× |
| 12mm | 254× |
Eyepieces are separate purchases. These are calculated examples, not guaranteed usable powers on every night. Begin at lower power, centre the target and increase magnification while the view continues to improve.
Configure the rear optical path.
Two 25mm and one 50mm extension rings are supplied. Select the combination that positions the focuser appropriately for your diagonal or camera arrangement.
Installing every ring is not a universal setup. Assemble the intended accessories, establish where focus falls and leave useful focuser travel available. Keep notes of successful arrangements so a change between observing and imaging is repeatable.
If additional optical elements are fitted, check their own spacing and connection requirements separately from the telescope’s mechanical extension.
Prepare the system before a long imaging run.
Practise acquiring a target at the native focal length before adding amplification. A small camera sensor can give a very narrow field, so an accurately aligned finder and steady tracking are valuable.
Use short test captures to establish focus and exposure. Choose a Barlow around the camera’s pixel size and the seeing. For long-exposure work, assess guiding and the full image field before committing to a sequence.
The supplier quotes a 55mm illuminated field. Illumination is not a guarantee of a flat, fully corrected image across a large sensor, and adapters can restrict the usable field. Check actual corner performance and the complete optical train for your proposed camera.
Alignment and cooling still matter.
Allow time for thermal settling and assess a well-centred star before making alignment changes. Use a procedure appropriate to a Classical Cassegrain, and distinguish focus, seeing and tracking problems from collimation.
Make one adjustment at a time and keep a record. Avoid disturbing an already sound alignment simply because a low-altitude target is shimmering or the telescope has just been brought outside.
Included and purchased separately
| Supplied with the OTA | Choose separately |
|---|---|
| Carbon-truss Classical Cassegrain and focuser | Suitable mount and tripod or pier |
| Upper and lower rails; finder base | Finder and any guiding equipment |
| 2-inch to 1.25-inch adapter | Diagonal and eyepieces for visual use |
| Two 25mm and one 50mm extension rings | Camera, connection adapters and any amplification optics |
Specifications at a glance
| Design / aperture | Classical Cassegrain / 250mm |
|---|---|
| Focal length / nominal ratio | 3045mm / f/12 |
| Mirror material | Quartz primary and secondary |
| Published length / end-ring diameter | 690mm / 400mm |
| Published tube weight | 17.2kg |
Before ordering
Is this a complete observing or imaging kit?
No. It is an optical tube assembly. Choose the mount, finder, diagonal and eyepieces or camera separately, and budget for the adapters and support equipment needed by your actual setup.
Does the truss make it an easy portable telescope?
Assess the size and total working weight against your own transport and installation arrangements. Plan secure support during fitting and removal, plus suitable protection for the open structure.
Should I compare it with the 8-inch model?
Compare target framing, mount requirements and the full kit’s handling. The 8-inch Classical Cassegrain is a smaller option worth considering when storage and transport shape your observing routine.
Availability reflects supplier stock and may change. Contact Dark Clear Skies to confirm dispatch timing if you need the telescope for a particular date.