DCS 2″ Dielectric Mirror Diagonal — 99% Reflectivity
Enjoy a more comfortable view of the night sky with the Dark Clear Skies 2″ 90° dielectric mirror diagonal. Its multi-layer dielectric mirror coating offers 99% reflectivity, while the included 2″ to 1.25″ adapter lets you use both popular eyepiece sizes.
Designed for visual observing with compatible refractors and Cassegrain telescopes, it turns the light path through 90° so you can look down into the eyepiece when your telescope points high in the sky.
Made for comfortable visual observing
- 99% reflective dielectric mirror: multi-layer coatings help keep light loss at the diagonal low.
- 2″ and 1.25″ eyepieces: use a 2″ eyepiece directly, or fit the supplied reducer for a 1.25″ eyepiece.
- 90° viewing angle: a practical choice for lunar, planetary and deep-sky observing, particularly with targets high overhead.
- Metal construction: a black aluminium housing with a red DCS side plate and knurled retaining screws.
- Supplied with protection: dust caps and a storage box help keep the diagonal covered between sessions.
Will it fit my telescope?
The telescope side requires a compatible 2″ eyepiece receiver or focuser. Refractors with a suitable 2″ focuser are the usual application. Schmidt-Cassegrain and Maksutov-Cassegrain telescopes need a suitable 2″ visual back or adapter if they do not already have one.
Check that your telescope has enough focus travel for a 2″ diagonal and your chosen eyepiece. The included 1.25″ adapter reduces the eyepiece holder; it does not allow the diagonal's 2″ telescope barrel to fit a 1.25″ focuser.
Specifications
| Optical design | Mirror diagonal |
|---|---|
| Viewing angle | 90° |
| Mirror coating | Multi-layer dielectric |
| Reflectivity | 99% |
| Telescope connection | 2″ barrel |
| Eyepiece sizes | 2″ directly; 1.25″ with the included adapter |
| Housing | Black aluminium with red DCS side plate |
| Primary use | Visual astronomy |
What is included?
- 1 × DCS 2″ 99% dielectric mirror diagonal
- 1 × 2″ to 1.25″ eyepiece adapter
- Dust caps
- Storage box
Which way round will the view appear?
In a normal refractor or Cassegrain visual setup, a mirror diagonal gives an upright image with left and right reversed. This is normal for astronomical viewing; it is not a correct-image terrestrial diagonal.
Looking after your diagonal
Refit the dust caps after use and store the diagonal in its box. Avoid touching the mirror surface and use appropriate optical cleaning methods only when cleaning is needed.