1. Waves, Light & Quanta Tim Freegarde Web Gallery of Art; National Gallery, London

2. 2 Principles of imaging S lenses can affect only the apparent position of an observed object P rays from the focus are collimated parallel rays converge on the focus central rays are not deviated a lens is characterized by its focal length or power (dioptres)

3. 3 Principles of imaging S REAL OBJECT S VIRTUAL OBJECT P REAL IMAGE VIRTUAL IMAGE P

4. 4 Imaging sign conventions REAL IS POSITIVE object distance image distance lens power surface radius of curvature from object to lens from lens to image converging positive from surface to centre LENSES converging (biconvex) diverging (biconcave) f positive f negative

5. 5 Lens system analysis RAY TRACING RULES rays from the focus are collimated parallel rays converge on the focus central rays are not deviated OBJECT AND IMAGE DISTANCES RAY TRANSFER MATRICES

6. 6 Telescopes and binoculars RAY TRACING RULES rays from the focus are collimated parallel rays converge on the focus central rays are not deviated OBJECT AND IMAGE DISTANCES lenses can affect only the apparent position of an observed object

7. 7 Telescopes and binoculars S fofo fofo fefe fefe p1p1 s1s1 s2s2 p2p2 rays from the focus are collimated parallel rays converge on the focus central rays are not deviated

8. 8 Telescopes and binoculars