Textbook Notes (378,720)
CA (167,253)
UTSG (10,976)
AST (204)
AST201H1 (66)
Chapter 6

# CHAPTER 6 ASTRO.docx

2 Pages
91 Views

Department
Astronomy & Astrophysics
Course Code
AST201H1
Professor
Michael Reid

This preview shows half of the first page. Sign up to view the full 2 pages of the document.
CHAPTER 6
TELESCOPES
6.1
Refraction is the bending of a wave
Nowadays, most images are recorded digitally with electronic detectors called charge
coupled devices (CCDs). A CCD is a chip of silicon is chip that is extremely sensitive to
photons. Its physically divided into a grid of squares called picture elements (pixels)
Advantages of CCDs over photographic film: much more sensitive to light; have a much
wider dynamic range which allows it to record dim and bright light at the same time; can
be digitally processed to bring out the details of the image
6.2
2 most important properties of a telescope: light collecting area and angular resolution
a 10m telescope has a light collecting area 25 times greater than a 2m telescope
([10/2]^2 = 25)
angular resolution is the SMALLEST angle over which we can tell two dots or two stars
are distinct (Human angular resolution is 1/60 degrees)
Hubble space telescope (2.4m) has a angular resolution of about 0.05 arcsecond for
visible light
The angular resolution that a telescope could achieve if it were limited only by the
interference of light waves is also called diffraction limit (depends on diameter of
telescope and wavelength of light)
The larger the telescope, the smaller the diffraction limit which leads to a better
(smaller) angular resolution
2 basic designs of telescopes: refracting and reflecting telescope
A refracting telescope uses lenses to collect and focus light
A reflecting telescope uses precisely curved primary mirrors to gather light
Observations through the telescope fall into 3 categories: imaging (photographs),
spectroscopy (study spectra) and timing (changes with time)
Nowadays, most astronauts use invisible light to record images
Spectrographs use diffraction gratings to separate the various colors of light into
spectra, which are then recorded with a detector such as a CCD

#### Loved by over 2.2 million students

Over 90% improved by at least one letter grade.

OneClass has been such a huge help in my studies at UofT especially since I am a transfer student. OneClass is the study buddy I never had before and definitely gives me the extra push to get from a B to an A!

Leah — University of Toronto

Balancing social life With academics can be difficult, that is why I'm so glad that OneClass is out there where I can find the top notes for all of my classes. Now I can be the all-star student I want to be.

Saarim — University of Michigan

As a college student living on a college budget, I love how easy it is to earn gift cards just by submitting my notes.

Jenna — University of Wisconsin

OneClass has allowed me to catch up with my most difficult course! #lifesaver

Anne — University of California
Description
CHAPTER 6 TELESCOPES 61Refraction is the bending of a waveNowadays most images are recorded digitally with electronic detectors called charge coupled devices CCDs A CCD is a chip of silicon is chip that is extremely sensitive to photons Its physically divided into a grid of squares called picture elements pixelsAdvantages of CCDs over photographic film much more sensitive to light have a much wider dynamic range which allows it to record dim and bright light at the same time can be digitally processed to bring out the details of the image 622 most important properties of a telescope light collecting area and angular resolutiona 10m telescope has a light collecting area 25 times greater than a 2m telescope 102225angular resolution is the SMALLEST angle over which we can tell two dots or two stars are distinct Human angular resolution is 160 degreesHubble space telescope 24m has a angular
More Less

Only half of the first page are available for preview. Some parts have been intentionally blurred.

Unlock Document

Unlock to view full version

Unlock Document
Notes
Practice
Earn
Me

OR

Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Join to view

OR

By registering, I agree to the Terms and Privacy Policies
Just a few more details

So we can recommend you notes for your school.