Republic of the Philippines
UNIVERSITY OF EASTERN PHIIPPINES
LAOANG CAMPUS
Laoang, Northern Samar
NAME OF PRESENTER/S : PAMELA FLORES
COURSE/YEAR
: BSED 3-B SCIENCE
TITLE/TOPIC
: THE UNIVERSE
COURSE INSTRUCTOR : MR. GEROBEL VALENZUELA
Astronomy (Research on simplicity and complexity of telescopes; evolution of
telescopes; A4; description, time, diagram; can be computerized for all
components
Telescopes: Simplicity and Complexity
Simplicity:
Early refracting telescopes were relatively simple in design, using just lenses to
magnify objects. They allowed astronomers to make groundbreaking observations,
such as Galileo's discovery of Jupiter's moons. However, their limitations in image
quality drove the development of more complex solutions. A telescope, at its simplest,
is an optical instrument designed to magnify distant objects. The basic design consists
of two lenses: an objective lens (or mirror) that gathers light and focuses it to a point,
and an eyepiece lens that magnifies the focused image for observation. This basic
setup, known as a refracting telescope, is easy to understand and construct.
Complexity:
Reflecting telescopes introduced complexity with mirrors, but they significantly
improved image quality by eliminating chromatic aberration. Over time, telescopes
became more intricate with compound designs, sophisticated mountings, and
advanced instruments for capturing different wavelengths of light. As our
understanding of optics and technology evolved, telescopes became more complex
and sophisticated. The introduction of reflecting telescopes, which use mirrors instead
of lenses, was a significant development. These telescopes eliminate chromatic
aberration (color distortion) inherent in refracting telescopes and can be made larger
without exponentially increasing their weight. Modern telescopes are now equipped
with various components, including precise mounts for tracking celestial objects,
computerized systems for automated pointing and imaging, and advanced detectors
for capturing light.
Modern Advances:
Space telescopes exemplify complexity by requiring precise engineering for launch,
deployment, and communication. Adaptive optics add complexity to ground-based
telescopes, incorporating real-time computer-controlled adjustments to counter
atmospheric effects.
Evolution of Telescopes:
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Refracting Telescopes: The first telescopes, developed in the early 17th
century, were refracting telescopes. They used lenses to bend and focus light,
magnifying distant objects. However, these telescopes suffered from chromatic
aberration - different colors of light focusing at different points, leading to image
distortion.
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Reflecting Telescopes: To overcome the limitations of refracting telescopes,
Isaac Newton introduced the reflecting telescope in the mid-17th century.
These telescopes use mirrors to reflect and focus light, avoiding chromatic
aberration and allowing for larger aperture designs.
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Compound Telescopes: Compound telescopes, also known as catadioptric
telescopes, combine lenses and mirrors to achieve a balance between compact
design and image quality. Examples include Schmidt-Cassegrain and
Maksutov-Cassegrain telescopes.
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Radio Telescopes: In the 20th century, astronomers expanded their
observations beyond visible light by developing radio telescopes. These
telescopes detect radio waves emitted by celestial objects, providing insights
into the universe's radio emissions, including distant galaxies and cosmic
background radiation.

Space Telescopes: Placing telescopes in space eliminates the distortion
caused by Earth's atmosphere. The Hubble Space Telescope is a prime
example, capturing stunning images of distant galaxies, nebulae, and other
cosmic phenomena.
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Adaptive Optics: To counter the blurring effects of Earth's atmosphere on
ground-based telescopes, adaptive optics technology was developed. It
involves real-time adjustments of the telescope's mirrors to compensate for
atmospheric distortions.
Evolution of Telescopes:
1. Galilean Telescope (1609):
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Diagram: Galilean Telescope Diagram
Description: The Galilean telescope, invented by Galileo Galilei,
consisted of a convex objective lens and a concave eyepiece lens. It
produced an upright, magnified image.
Explanation: Light entered through the objective lens, forming an
inverted real image. The eyepiece lens magnified this image for
observation.
Keplerian Telescope (1611):
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Diagram: Keplerian Telescope Diagram
Description: Johannes Kepler improved the design with a convex
objective and convex eyepiece lens. This produced an inverted image
that allowed for higher magnification.
Explanation: The objective lens formed an inverted real image, and the
eyepiece lens magnified it. This design reduced aberrations.
Newtonian Reflecting Telescope (1668):
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Diagram: Newtonian Telescope Diagram
Description: Isaac Newton introduced the reflecting telescope, using a curved
mirror as the objective instead of a lens. A flat diagonal mirror reflected the
image to an eyepiece on the side of the telescope.
Explanation: Light collected by the mirror was reflected to the side of the
telescope, allowing for easier observation.
Hubble Space Telescope (1990):
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Diagram: Hubble Space Telescope
Description: The Hubble Space Telescope is a space-based observatory with
a 2.4-meter primary mirror. It orbits Earth and captures images using various
instruments across the electromagnetic spectrum.
Explanation: Hubble's position above Earth's atmosphere eliminates distortion
and allows for stunning images of distant celestial objects.
James Webb Space Telescope (Upcoming):
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Diagram: JWST Diagram
Description: The James Webb Space Telescope (JWST) is a highly
anticipated successor to Hubble. It's optimized for infrared observations and
has a large segmented mirror.
Explanation: JWST's advanced technology will enable us to study the universe
in unprecedented detail, revealing information about distant galaxies, stars, and
planetary systems.
1608: Lippershey's Refracting Telescope
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Description: In 1608, Dutch spectacle maker Hans Lippershey created one of
the earliest known refracting telescopes. It consisted of a convex objective lens
and a concave eyepiece lens, enclosed within a tube. When pointed at distant
objects, it produced magnified images, thus allowing for significant
advancements in astronomical observation.
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Explanation: Lippershey's telescope marked a pivotal moment by introducing
a practical instrument that could magnify distant objects, leading to
groundbreaking astronomical discoveries by Galileo Galilei and Johannes
Kepler.
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Time: Early 17th century (1608)
1672: Cassegrain Telescope Concept
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Description: The Cassegrain telescope, conceived by French priest Laurent
Cassegrain in 1672, is a type of reflecting telescope. It involves light entering
the telescope through an aperture and reflecting off a primary mirror onto a
secondary mirror, which then directs the light to an eyepiece or detector.
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Explanation: Cassegrain's concept expanded the possibilities of telescope
design, enabling longer focal lengths in a more compact instrument, which was
especially beneficial for astronomical observatories with limited space.
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Time: Late 17th century (1672)
1780s: Achromatic Lenses Introduced
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Description: Achromatic lenses are lens systems that consist of two or more
lenses made of different types of glass. They were introduced in the 18th
century to address chromatic aberration, a problem that caused colored fringes
around objects when using simple lenses.
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Explanation: Achromatic lenses combined different glass types to minimize
chromatic aberration by refracting different colors of light by varying amounts.
This advancement greatly improved the quality of images produced by
refracting telescopes.
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Time: 1780s
1845: Large Refractor at Pulkovo Observatory
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Description: The Great Refractor at the Pulkovo Observatory in Russia,
completed in 1845, was a massive refracting telescope with a 15-inch (38 cm)
diameter lens. It was one of the largest refracting telescopes of its time and
played a significant role in advancing observational astronomy.
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Explanation: Large refracting telescopes like the one at Pulkovo Observatory
allowed astronomers to observe celestial objects with greater detail and clarity.
Its impressive size and precision optics contributed to groundbreaking
discoveries
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Time: 1845
1923: Schmidt-Cassegrain Telescope
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Description: The Schmidt-Cassegrain telescope, developed by Bernhard
Schmidt in 1931 but popularized in the 20th century, combines elements of both
the Cassegrain and Schmidt camera designs. It features a corrector plate at the
front to eliminate spherical aberration and coma, resulting in a compact yet
high-performance instrument.
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Explanation: The Schmidt-Cassegrain design revolutionized amateur
astronomy by providing a compact and versatile instrument capable of
capturing deep-sky images. Its popularity surged due to its ease of use and
portability.
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Time: 1923