Primary mirror 250/1000 - Sky-Watcher parabolic mirror for Newtonian reflectors
Looking for a reliable replacement primary mirror for your Newtonian telescope? The Sky-Watcher parabolic primary mirror with a diameter of 250 mm and a focal length of 1000 mm is a precision-ground optical component designed specifically for Newtonian reflectors. Whether you are restoring existing optics or building your own custom telescope, this mirror provides a solid foundation for quality sky observation.
Why a parabolic mirror?
A parabolic primary mirror for a Newtonian telescope offers a fundamental advantage over spherical grinding - it eliminates spherical aberration, which at a focal ratio of f/4 would cause significant blurring of star points towards the edge of the field of view. The parabolic shape ensures that parallel rays of light are focused into a single focal point regardless of where on the mirror surface they land.
For an aperture of 250 mm and a focal length of 1000 mm, parabolic grinding is an absolute necessity - no compromise in the form of a spherical mirror would deliver satisfactory results at this f/4 ratio.
Key specifications
| Parameter |
Value |
| Mirror diameter |
250 mm (10″) |
| Focal length |
1000 mm |
| Focal ratio |
f/4 |
| Mirror type |
Parabolic primary mirror |
| Intended use |
Newtonian and Dobsonian reflectors |
| Brand |
Sky-Watcher |
Performance - visual observing and astrophotography
A 250 mm (10″) mirror at f/4 is an excellent choice for both visual observing and astrophotography:
- The large aperture allows you to capture faint deep-sky objects - nebulae, galaxies and globular clusters.
- The short focal length of 1000 mm keeps the telescope tube relatively compact even with such a large light-collecting surface.
- For astrophotographers this means a fast optical system capable of capturing extended objects with shorter exposure times.
Compatibility and installation
The mirror is intended as a replacement primary mirror for Sky-Watcher Newtonian reflectors with matching dimensions, but thanks to its standardised parameters it can also be used when building a custom Dobsonian or Newtonian telescope. When replacing or installing the mirror, careful collimation is essential - precise alignment of the primary and secondary mirror is the key to achieving maximum optical performance of the entire system.
Sky-Watcher quality
Sky-Watcher is one of the world's leading manufacturers of astronomical optics with a long tradition and strict output quality control. Their mirrors undergo thorough inspection of the grinding quality and reflective coating, so you can count on high reflectivity and an accurate optical surface straight out of the box.
