Sky-Watcher primary mirror 130/900
If you are looking for a quality replacement or upgrade for your Newtonian reflector, you are in the right place. This primary mirror from Sky-Watcher is manufactured with emphasis on precision grinding and the quality of the reflective coating - the properties that truly matter in astronomy. Whether you need to replace a damaged mirror or want to improve the optical performance of your optical tube, this mirror provides a reliable foundation for observing the night sky.
Key optical parameters
Primary mirror for a Newtonian reflector with a 130 mm aperture and 900 mm focal length is a popular choice among amateur astronomers thanks to its combination of compact dimensions and a favourable focal ratio of f/6.9. This parameter ensures good results both when observing planets and the Moon, and when viewing bright nebulae and star clusters. The mirror is compatible with a wide range of standard Newtonian-type tubes of the corresponding diameter.
| Parameter |
Value |
| Mirror type |
Primary mirror for Newtonian reflector |
| Aperture |
130 mm |
| Focal length |
900 mm |
| Focal ratio |
f/6.9 |
| Weight |
580 g |
| Coating |
Aluminium with SiO2 protective layer |
| Mirror cell compatibility |
Standard 3-point primary mirror cell |
Why the primary mirror matters
The primary mirror is the heart of every reflector - all light from the observed object is gathered at its surface before travelling on to the secondary mirror and the eyepiece. Any inaccuracy in the mirror's geometry or shortcomings of the reflective coating are therefore directly reflected in the quality of the resulting image.
Sky-Watcher pays close attention to precise parabolisation of its optical components and applies a quality aluminium coating with a protective layer of silicon dioxide (SiO2). This ensures high reflectivity and long surface durability even under typical astronomical use conditions.
Installation and collimation
The weight of 580 g is entirely standard for this aperture, and installing the mirror in a tube requires no special modifications - the mirror sits in the standard 3-point primary mirror cell that is part of the tubes of compatible instruments. When replacing the mirror, we recommend paying attention to proper collimation after installation, as precise optical alignment is essential for achieving a sharp image.
Installation tips
- The mirror fits a standard 3-point primary mirror cell - no tube modifications needed.
- After mounting, always perform a full collimation of the optical system.
- Handle the mirror surface carefully - avoid touching the coated face.
- Clean the coating only when necessary and use appropriate methods for aluminised optics.
Who is this mirror for?
This Sky-Watcher 130/900 replacement mirror is the right choice for anyone who wants to preserve or restore the full optical potential of their telescope without having to purchase an entirely new instrument. It is a practical and cost-effective way to extend the life of a favourite optical tube or to experiment with building your own optical system.
The mirror will be especially appreciated by:
- More experienced amateur astronomers who carry out maintenance and adjustment of their instruments themselves.
- ATM (Amateur Telescope Making) enthusiasts who are building their own telescopes and are looking for reliable optics from a proven manufacturer.
- Users who need to replace a damaged or degraded mirror in an existing Sky-Watcher 130/900 tube.
About Sky-Watcher
Sky-Watcher is a world-renowned brand with a long tradition in the manufacture of astronomical optics. Its products are respected by the astronomical community around the world, and the brand is a trusted choice for both beginners and experienced observers.
