History of the Telescope
Introduction
The telescope is an instrument which increases our ability to observe far away objects through the collection of electromagnetic radiation, the most prevalent type of telescope is the optical telescope which collects light, however there are other kinds of telescopes which collect UV and X -Rays. Optical telescopes use lenses to redirect light to a specified point. Different lenses are used for different magnifications of celestial objects. This essay will be mainly discussing optical telescopes.
As we go through the history of optical telescope we can see that there are a few concepts that are fundamental to all the different types of optical telescopes, from the reflecting to the refracting to the hybrid of the two these are as follows.
The lens and its properties were known prior to the invention of the optical telescope with simple lenses made from rock crystal being found before recorded history (George & Yannis, 1987). The properties of light such as reflection, refraction and colour were discussed by Ptolemy in his work ‘Optics’ written in the 2nd century (Salih, Al Amri, & El Gomati, 2005) and by the 12th Century ‘reading lenses’, the predecessors to the magnifying glasses, were in use by people suffering from sight deficits (White, 1961).
All telescopes have a hole or opening through which light travels called the aperture. This relates to the telescope’s ability to collect light through a lens or mirror, with the bigger the aperture the more light it is able to collect and bring to focus, and the brighter the final image. The focal length of a telescope is the distance required by the objective lens or primary mirror to bring all the light it has collected to a single point (focal point). As a general rule of thumb, the longer the focal length of a telescope the more capable of the telescope to deliver higher magnifications. Finally, the resolution of a telescope is the ability to see fine details in an
The telescope is an instrument which increases our ability to observe far away objects through the collection of electromagnetic radiation, the most prevalent type of telescope is the optical telescope which collects light, however there are other kinds of telescopes which collect UV and X -Rays. Optical telescopes use lenses to redirect light to a specified point. Different lenses are used for different magnifications of celestial objects. This essay will be mainly discussing optical telescopes.
As we go through the history of optical telescope we can see that there are a few concepts that are fundamental to all the different types of optical telescopes, from the reflecting to the refracting to the hybrid of the two these are as follows.
The lens and its properties were known prior to the invention of the optical telescope with simple lenses made from rock crystal being found before recorded history (George & Yannis, 1987). The properties of light such as reflection, refraction and colour were discussed by Ptolemy in his work ‘Optics’ written in the 2nd century (Salih, Al Amri, & El Gomati, 2005) and by the 12th Century ‘reading lenses’, the predecessors to the magnifying glasses, were in use by people suffering from sight deficits (White, 1961).
All telescopes have a hole or opening through which light travels called the aperture. This relates to the telescope’s ability to collect light through a lens or mirror, with the bigger the aperture the more light it is able to collect and bring to focus, and the brighter the final image. The focal length of a telescope is the distance required by the objective lens or primary mirror to bring all the light it has collected to a single point (focal point). As a general rule of thumb, the longer the focal length of a telescope the more capable of the telescope to deliver higher magnifications. Finally, the resolution of a telescope is the ability to see fine details in an
Bibliography: Delehanty, M. (n.d.). All about telescopes: refractors, reflectors and more. Retrieved 05 15, 2011, from Astronomy Today: http://www.astronomytoday.com/astronomy/telescopes.html Drake, S George , S., & Yannis, S. A. (1987). Lenses in Antiquity. American Jounral of Archaeology, 191-196. King, H. C. (2003). THe History of the Telescope. Cambridge: Courier Dover Publications. Plotner, T. (2008, July 23). Reflector Telescope. Retrieved 05 15, 2011, from Universe Today: http://www.universetoday.com/15849/reflector-telescope/ Plotner, T Salih, H., Al Amri, M., & El Gomati, E. (2005). The miracle of light. A World of Science, 2-7. Strobel, N. (2011, 01 07). Telescopes. Retrieved 5 15, 2011, from Astronomy Notes: http://www.astronomynotes.com/telescop/s1.htm White, L