Telescope
Article by: Jay M. Pasachoff, Hopkins Observatory, Williams College, Williamstown, Massachusetts.
Robert D. Chapman, Laboratory for Solar Physics and Astrophysics, Goddard Space Flight Center,
National Aeronautics and Space Administration, Beltsville, Maryland.
Access to this content is available to Ward's World readers for free
from McGraw Hill's AccessScience, an award-winning, digital STEM
resource that provides immediate, authoritative answers to students' thirst
for scientific knowledge on topics such as climate change, virology,
pollution, and more. Ward's World and McGraw Hill have partnered to
offer educators a no-obligation, free trial subscription to this product.
Request your free trial today and discover how valuable AccessScience
can be for you and your students.
An instrument used to collect, measure, or analyze electro-
magnetic or other radiation from distant objects. A telescope
overcomes the limitations of the human vision by increasing the
ability to see faint objects and discern fine details. In addition,
when used in conjunction with modern detectors, a telescope
can "see" light that is otherwise invisible to the human eye (Fig.
1). The wavelength of the light of interest can have a profound
effect on the design of a telescope. By analogy, detectors of
particles from space are also known as telescopes.
History
The first substantiated record of the invention of the telescope
dates back to 1608 CE, when the Dutch eyeglass maker Hans
Lippershey sought a patent for an optical magnifying device.
The Italian physicist and astronomer Galileo heard reports of
this invention and crafted his own telescope in 1609. With this
instrument, Galileo made the first astronomical observations
of bodies including the Moon, Sun, planets of the solar system,
and distant stars (Fig. 2).
+
ward
'
s
science
Content
• History
• Optical telescopes
• Refracting telescopes
• Reflecting telescopes
• Catadioptric telescopes
• Solar telescopes
• Radio telescopes
• Infrared telescopes
• Ultraviolet telescopes
• X-ray telescopes
• Gamma-ray telescopes
• Cosmic-ray telescopes
• Neutrino telescopes
Key Concepts
• A telescope is an instrument used to collect, measure, or analyze electromagnetic
or other radiation from distant objects.
• There are about as many different kinds of telescopes as there are types of radiation;
these include optical (visible light), solar, radio, infrared, ultraviolet, x-ray, gamma-ray,
cosmic-ray, and neutrino telescopes.
• The three basic kinds of optical telescope are refracting telescopes, which focus light
with lenses, involving lenses; reflecting systems, which use mirrors; and catadioptric
systems, which use a combination of lenses and mirrors.
• Astronomers use spectrographs, charge-coupled devices (CCDs), adaptive optics,
interferometry, and other technologies to augment telescope performance and
overcome the limits of poor seeing.
