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Unformatted text preview: There are a wide range of wavelengths
of electromagnetic waves.
Only a very small range of
wavelengths, 400nm to 700nm, is
visible to humans What types of telescopes do
you construct on the ground?
A and C This replica of Newton’s
reflecting telescope built in
This reflecting telescope has a
spherical primary mirror 3 cm
(1.3 in.) in diameter. Its
magnification was 40x. A Newtonian telescope Light-Gathering Power is proportional to
the area of mirror. New technology has created charge-coupled
devices (CCDs) that gather light more
efficiently than photographic plates. This image of the Rosette Nebula, a region of star
formation 5000 ly away in the constellation
Monoceros (the Unicorn), was taken with this
CCD. It shows the incredible detail that can be
recorded by large telescopes and high-resolution
CCDs. These three views of the same part of the sky, each taken with
the same 4-m telescope, compare CCDs to photographic plates.
(a) A negative print of a photographic image.
(b) A negative CCD image. Notice that many faint stars and
galaxies that are invisible in the ordinary photograph can be
seen clearly in this CCD image.
(c) This (positive) color view was produced by combining a
series of CCD images taken through colored filters. A. Different colors of light are
refracted differently and have
different focal points. Thus, all
the colors of the image will
not be focused at once. This
is called chromatic aberration.
B. The weight of a large lens can
cause the lens to sag and
distort the image.
C. Air bubbles in the glass cause
distorting the image
D. Glass is opaque to certain
wavelengths of light, meaning Yerkes Observatory A. To make each 8.4-m primary mirror for the Large Binocular
Telescope II on Mount Graham in Arizona, 40,000 pounds of
glass are loaded into a rotating furnace and heated to 1450
K (2150°F). This image shows glass fragments loaded into
the cylindrical furnace.
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This note was uploaded on 02/03/2014 for the course PHYS 1150 taught by Professor Satoshi during the Spring '08 term at Auburn University.
- Spring '08