15 Optical Instruments
"Gemini Observatory at sunset" by Mailseth
"Gemini South 01"
by Denys
Sections
15.1 Two lens system 15.2 Simple Magnifiers
15.3 Compound Microscope s 15.4 Refracting Telescope 15.5 Cameras
15.6 Eyes
15.1 Two Lens System
Total magnification:
If M is positive, the final image has same the orientation as the object.
Image produced by a system of two thin lenses
Image produced by a system of two thin lenses
Lens 1
Lens 2
15.2 Simple Magnifiers
q ≈ h/25
q’
≈ h/f15.3 Compound Microscope
15.4 Refracting Telescope
q
ey/q
obq
ob ≈ h/
fob andq
ey ≈ h/feyThe astronomical telescope
• The optical system of an astronomical refracting telescope.
The reflecting telescope
• Three designs for reflecting telescopes. Part (d) shows the Gemini North telescope, which uses the design in (c) with an objective mirror 8 meters in diameter.
SPHERICAL ABERRATION
• The Hubble Space Telescope
15.5 Cameras
A digital Camera
Camera lens basics
15.6 The eye
• The optical behavior of the eye is similar to that of a camera.
Defects of vision
• The near point typically recedes with age, as shown in Table 34.1.
• Figure at right shows a normal, a myopic, and a hyperopic eye.
Farsighted correction
• Figure below shows how to correct a hyperopic (farsighted) eye using a converging lens.
Nearsighted correction
• Figure below shows how to correct a myopic (nearsighted) eye using a diverging lens.
Correcting for farsightedness
1 1 1 1 1
2.5cm 100cm
33cm power = 1 3 diopters
f p i
f f
Correcting for nearsightedness
1 1 1 1 1
48cm
48cm power = 1 2.1 diopters
f p i
f f
