New main: Star Digaonals & Mirrors

A star diagonal, also known as a mirror diagonal or simply a diagonal, is an accessory that is used to redirect the light path in a telescope at a right angle. This allows the observer to look through the telescope at a more comfortable angle, rather than having to look straight down into the eyepiece.

Most star diagonals consist of a mirror or prism that is mounted at a 45-degree angle to the telescope's optical axis. Light entering the telescope is reflected off the diagonal and redirected at a right angle, making it easier for the observer to look through the eyepiece. Star diagonals are particularly useful when observing objects that are high in the sky, as they allow the observer to maintain a more comfortable viewing position. They are also commonly used in terrestrial observing, where they can help to avoid neck strain or discomfort when looking through a telescope for extended periods of time. 

Astronz only sells dielectric diagonals, which are a type of star diagonal used in telescopes that is designed to reflect light using a highly reflective dielectric coating rather than a metal coating. Dielectric coatings are typically made from several thin layers of different materials, such as titanium dioxide or silicon dioxide, that are deposited on the surface of the diagonal using a specialised process. These coatings are highly reflective and can reflect up to 99% of the light that strikes them.

Secondary Mirrors:

The secondary mirror in a telescope is a smaller mirror that is positioned in the light path between the primary mirror and the eyepiece or camera. Its purpose is to reflect the light from the primary mirror and redirect it out the side of the telescope, toward the eyepiece or camera.

The secondary mirror is typically mounted on a diagonal or flat surface, and is positioned at a 45-degree angle to the light path. This allows it to reflect the light at a right angle to the eyepiece or camera, making it easier for the observer or imager to see or photograph the object being observed.

Parabolic Mirrors:

A parabolic mirror is a type of curved mirror used in telescopes and other optical systems. It is shaped like a paraboloid, which is a three-dimensional curve that has the property that every ray of light that enters the mirror parallel to its axis is reflected toward a single point known as the focus.

The parabolic mirror is an important component of many reflecting telescopes, which use mirrors to gather and focus light rather than lenses. When light from a distant object enters the telescope, it is reflected by the parabolic mirror and focused at the focal point. An eyepiece or camera is then placed at the focal point to view or capture the image.