1. Lesson 6 – Microscope and telescope
Construct a ray diagram for a compound microscope with final image formed close to the near point of the eye (normal adjustment). Students should be familiar with the terms objective lens and eyepiece lens.
Construct a ray diagram for an astronomical telescope with the final image at infinity (normal adjustment).
State the equation relating angular magnification to the focal lengths of the lenses in an astronomical telescope in normal adjustment.
Solve problems involving the compound microscope and the astronomical telescope (Problems can be solved either by scale ray diagrams or by calculation).

2. Compound microscope

3. Using a microscope – Making onion skin slides practical (Year 7!!!!)
Eyepiece lens
Objective lens

5. The object is placed at a distance just beyond the focal lens of the objective lens (so a short focal length is used)

6. A real inverted image is produced closer to the eyepiece lens than the focal length

7. The real image acts as an object for the eye piece lens
The real image acts as an object for the eye piece lens. The eyepiece lens thus acts like a simple magnifying glass in the image formed by the objective

8. Enlarged image seen by eye. Largest when image at near point of eye.

9. Let’s make a microscope using two lens and then let’s draw our own ray diagram for a microscope

10. Astronomical telescope
This is the 24 inch reflecting telescope at the Lowell Observatory in Flagstaff, Arizona, which was used to discover Pluto. Nearly all astronomical telescopes use mirrors rather than lenses, but we will learn how a telescope with lenses works.

11. Telescope – Ray diagram
Angular magnification = fo/fe

12. Let’s make a telescope!
Proud man