Name: Optical Instruments: Spectrometer
Uploaded: 2019-07-19
Duration: 7 min 33 s
Description: The basic function of a spectrometer is to take in light, break it into its spectral components, digitise the signal as a function of wavelength, and read it...

Question

Draw the labelled diagram of cassegrain telescope. Write the advantages of cassegrain telescope.

Accepted Answer

The Cassegrain reflector is a combination of a primary concave mirror and a secondary convex mirror, the main characteristic being that the optical path folds back onto itself, relative to the optical system's primary mirror entrance aperture. This design puts the focal point at a convenient location behind the primary mirror and the convex secondary adds a telephoto effect creating a much longer focal length in a mechanically short system. Below shows the diagram of Cassegrain telescope.

Following are the advantages of Cassegrain telescope:

In this telescope, the mirror is replaced by an objective lens. So there is no chance for chromatic and spherical aberrations.

The spherical aberration will be converted into parabolic aberration.

The appearance of the image in a reflecting telescope is brighter than that of the refracting telescope.

Another advantage of a Cassegrain reflecting telescope is, it requires only one side of polishing the image.

The lens is heavier than the mirror. So because of using lightweight mirrors, the apparatus requires less support.

Draw the labelled diagram of cassegrain telescope. Write the advantages of cassegrain telescope.

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