Advantages and Disadvantages of an Astronomical Telescope
The telescope which is used for viewing celestial bodies like sun, moon, planets, stars, etc. is called an astronomical telescope. It is an optical instrument that is used to see the magnified image of distant heavenly bodies like stars, planets, satellites, and galaxies, etc.
One of the first advantages of astronomical telescopes is their cost. These telescopes use lenses instead of mirrors. These lenses are considerably expensive and time-consuming to make. These telescopes use mirrors that are easier and less expensive to make. Therefore, these telescopes will usually cost five times less than the refracting variety.
While there are numerous advantages to these telescopes, they do have a few disadvantages. One of the first disadvantages deals with maintenance. The mirrors used in these telescopes need to be recoating after a few years in order to function properly. Another disadvantage of these telescopes deals with contrast. The second mirror used in the telescope will create a central obstruction.
Advantages of an astronomical telescope: Mainly four advantages are found in art astronomical telescope: viz—
- It creates large magnification,
- Superior resolving power per inch of aperture,
- Its field of view is wide,
- Superior performance in inferior conditions – image steadier,
- The image is free from aberration, not reflections or interruption of the light path,
- Long focal ratios can mean the use of longer focus, simpler, eyepieces
- Cross-wire and micrometer screws are used when needed.
Disadvantages of an astronomical telescope: In this instrument, two disadvantages are found; viz –
- A certain amount of secondary spectrum (chromatic aberration) unavoidable (reflector completely free of this),
- Long focal ratios can mean that the instrument is cumbersome,
- As the main tube is very long, so the instrument becomes quite large and
- As an inverted image is formed in this instrument, so it is not usable for observing objects at a long distance in front of the earth’s surface.