1. Telescopes
T02 - Calub
T08 - Li
T10 – Misola
Physics 3 Presentation

2. Definition
Telescopes – are instruments used to observe
remote, distant objects. It collects and focuses light coming
from the observed object, resulting to a clearer, magnified
image of it.
* We need magnification for our eyes don’t have enough space to see distant things. Pixel
example.

3. A Bit of History
• Coming from the word “tele” – far and “skopein” – As of now,
far seeing. from the simple
• Since its invention in 1608 by Hans Lippershy, it lens ancestor, it has
has been widely used in Astrophysics. Galileo was evolved into
considered the father of telescopes. gamma ray,
• Galileo first used a telescope for astronomical infrared telescopes,
purposes. basically the types
• Kepler improved the design further using two of electromagnetic
convex lenses. waves available.

4. • Properties
– Aperture – how well it can collect light.
• Larger diameter = more light = clearer view
– Magnification
• Factors affecting the performance of
telescopes in magnifying objects vary
depending on the following:
– Availability of Light in the Environment
– Combination of Lenses/Mirrors Used
• Thickness and focal length

5. Parts of a Telescope
• Objective Lens – collects lots of lights and focuses it into a
very small image at the focus.
•Eyepiece Lens – magnifies the focused image into a size that
perfectly fits into the viewer’s eyes.

7. Two Basic Types
• Reflecting • Refracting
– An optical telescope. – Also an optical
• Increases apparent telescope.
brightness of object, and – Primarily uses lenses.
its angular size.
– Invented earlier.
– Invented in the 17th
Century.
– More used nowadays in
astronomical labs.
– Mirror based.

8. Refracting
Telescope
• Uses concave objective
and convex ocular lens.
•Bends parallel lights
into a focal point to
create a clearer image.
•Angular magnification is
equal to the ratio of
objective focal length over
eyepiece focal length.
•Used in binoculars.

9. •Pros:
•Low Maintenance
•Clear and contrasting Images
•Ease of Usage
•Cons:
• Chromatic Aberration
• Fringes or Rainbow like
appearances at the points of
the images where dark and
light colors appear.
• Because of the different
wavelengths in a white light.
•Costs more.
•Not developed for Astronomical
Purposes.
• Light loss.

12. Reflecting
Telescope
•Commonly uses parabolic
primary mirror and angled
flat secondary mirror to focus
light into the eyepiece.
• Famous models are
Gregorian  First model built in
1688 by Newton.
and Newtonian telescopes.
•Easier to manufacture, Its popularity
increased with the
cheaper materials and less advent in silver
spherical abberations. coating, parabolic
mirror
manufacturing, seg
mented mirrors, etc.

13. •Pros
•Cheaper to manufacture
•More capable to detect faint
astronomical objects.
• Tends to have more compact
design.
•Cons
• The tube body can get easily
destroyed = high maintenance.
• Bulkier Design
•Spherical Abberation
•Higher magnification = smaller
field of view

15. Catadioptric
Telescopes
•Uses both lenses and
mirrors.
•Used widely in taking
highly accurate
magnifications/lighting .
I.e.: microscopes,
headlamps, etc.

16. Here are other types of Telescopes
Radio Telescopes

17. Gemini N Mauna Kea (4213 m), Hawaii
Gemini S Cerro Pachon (2722 m), Chile

18. William Herschel telescope 4.2 m, La Palma (2400 m), Canary Islands, Spain
Optical and IR

19. References
• http://science.howstuffworks.com/telescope3.htm
• http://webcache.googleusercontent.com/search?gcx=w&ix=c2&sourceid=chrome
&ie=UTF-8&q=cache%3Atelescopes.lifetips.com%2Fcat%2F64000%2Frefracting-
telescopes%2Findex.html
• http://webcache.googleusercontent.com/search?gcx=w&ix=c2&sourceid=chrome
&ie=UTF-8&q=cache%3Atelescopes.lifetips.com%2Fcat%2F63999%2Freflecting-
telescopes%2Findex.html
• http://en.wikipedia.org/wiki/Chromatic_aberration
• http://webcache.googleusercontent.com/search?q=cache:ZKn7pHGyE8EJ:www.ast
ro-
tom.com/technical_data/useful_formulas.htm+telescope+formulae&cd=1&hl=tl&c
t=clnk&gl=ph
• http://www.slideshare.net/radmila/telescopes-presentation
• http://www.slideshare.net/bergsa/HowTelescopesWork