Quick question about telescope classification

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Discussion Overview

The discussion revolves around the classification of telescopes, specifically the term 'astronomical telescope' and its distinction from terrestrial telescopes. Participants explore the definitions and characteristics of both refracting and reflecting telescopes in the context of their use in astronomy versus terrestrial observation.

Discussion Character

  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that 'astronomical telescope' refers specifically to refracting telescopes with an objective and eyepiece lens, while others argue that both reflecting and refracting telescopes can be classified as astronomical telescopes based on their intended use for observing celestial objects.
  • One participant recalls that astronomical telescopes are not designed to erect the image and require a separate accessory lens for that purpose.
  • A later reply asserts that most major astronomical telescopes are reflectors, citing the Hubble Space Telescope as an example, and mentions exceptions like the Yerkes Observatory and Lick Observatory, which house large refractors.
  • Another participant clarifies that terrestrial telescopes, including binoculars, are all refractors and highlights that the main difference between terrestrial and astronomical refractors is the presence of an additional lens in terrestrial telescopes to invert the image for upright viewing.

Areas of Agreement / Disagreement

Participants express differing views on the definition of astronomical telescopes, with no consensus reached on whether the term exclusively refers to refracting telescopes or includes both types. The discussion remains unresolved regarding the classification criteria.

Contextual Notes

There are limitations in the definitions provided, as they depend on specific interpretations and contexts of use. The discussion also reflects varying levels of familiarity with telescope design and terminology.

21joanna12
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I am slightly confused about what the term 'astronomical telescope' covers. My textbook seems to be implying that astronomical telescopes are refracting telescopes with an objective and eyepiece lens, and reflecting telescopes are separate to astronomical telescopes. On the other hand I have read some sources that seem to say that both reflecting and refracting telescopes can be astronomical telescopes because they are used to view planets/stars/moons and the opposite is a terrestrial telescope used for observing things on Earth. Could someone clear up this discrepancy?

Thank you in advance! :)
 
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"Astronomical telescope" usually means any telescope that is used (or designed to be used) for astronomy, regardless of optical design.
 
As I recall from my youth, when I built an 6" and an 8", astronomical telescopes are not intended to erect the image but require a separate accessory lens to do so.
 
21joanna12 said:
I am slightly confused about what the term 'astronomical telescope' covers. My textbook seems to be implying that astronomical telescopes are refracting telescopes with an objective and eyepiece lens, and reflecting telescopes are separate to astronomical telescopes

no that is totally incorrect
astronomical telescopes are either, infact all of the major astronomical scopes are reflectors ... even the Hubble Space Telescope

There are 2 exceptions, the Yerkes Observatory in WI, USA is a 40 inch refractor and the largest in the world ... was built in the 1890's
And the Lick Observatory on Mt Hamilton, CA, USA, which sports a 36" refractor, also built in the last 1880's

For amateur astronomy, I have owned both types, currently own 8" and 9.25" reflectors
21joanna12 said:
and the opposite is a terrestrial telescope used for observing things on Earth. Could someone clear up this discrepancy?

terrestrial telescopes ( including binoculars) are all refractors ... completely the opposite to your opening statement

The only difference between a terrestrial refractor and an astronomical refractor is that the terrestrial one has an extra lens built into it to invert the image so that it is upright for viewing. Some astronomical refractors may come with or have an accessory lens that can invert the image for terrestrial usecheers
Dave
 
Last edited:

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