What Are Catadioptric Telescopes?

A refracting telescope is an optical system that combines a refractive system with a reflective system. Its objective lens contains both a lens and a reflector. The light of a celestial body must be refracted and reflected at the same time. This system is characterized by easy correction of off-axis aberrations. Based on spherical mirrors, appropriate refractive elements are added to correct spherical aberrations to obtain good optical quality. The most widely used are the Schmidt telescope (Meade 12 "LX200SC in the United States), the Schmidt-Cassegrain system (KP300S at Nanjing Tianyi Center), the Maxutov and Maxutov-Cassegrain telescopes (Nanjing) Yufu Astronomy Science and Education Instrument Factory 160mm and other series) four types.

Refracting telescope

A refracting telescope is an optical system that combines a refractive system with a reflective system. Its objective lens contains both a lens and a reflector. The light of a celestial body must be refracted and reflected at the same time. This system is characterized by easy correction of off-axis aberrations. Based on spherical mirrors, appropriate refractive elements are added to correct spherical aberrations to obtain good optical quality. The most widely used is the Schmidt telescope (

The refracting telescope first appeared in 1814. In 1931,

1. Folding reflection telescope and shading system.

The outer lens barrel can provide proper shielding of the telescope group, and isolate the light from directly illuminating the primary and secondary reflectors, so that the source of stray light is mainly limited to direct light and scattered stray light from a small angle light source,

First, it must be able to exclude the direct light source effect to prevent the primary mirror, secondary mirror and the rear-end correction mirror group in the telescope group from being exposed to external light sources, such as direct sunlight.

Blocking out of perspective or not following

Advantages of the refracting telescope

1. Long focal length can be obtained with a short lens barrel, so it is easy to obtain high system magnification with eyepieces of general focal lengths;

When observing the sky with large-aperture reflecting telescopes, large aberrations are always unavoidable, and only a small part of the center can achieve better results.

Folding mirrors are divided into (1) pure Schmitt (2) Schmitt Gesellin (3) and Maxtorf's:

1.Pure Schmitt Mirror-dedicated to astrophotography

Refracting telescope

2. Schmidt Geiselin

3. The Maxtorf type has the characteristics of a mirror and reduces aberrations.

Therefore, if you are interested in planet and moon observation, please choose refractors and fold mirrors. If you are interested in nebulae and star clusters, please choose reflectors. If your financial ability permits, please buy as large a telescope as possible, because the larger the telescope diameter, the stronger the light collecting power. But also pay attention to the brand, because the brand is often directly proportional to the optical quality. Such as Nikon, ZEISS, Takahashi VIXEN (refractive mirror).