1. Modern Optics Lab Lab 3: Experiments with the Telemicroscope  Measuring: Focal lengths of thin lenses Real image magnification Virtual image magnification (simple magnifier) Compound microscope magnification Size of an unknown object Astronomical telescope magnification Entrance and exit pupils of telescope  Theory: The lens formula Transverse magnification Magnifier magnification Compound microscope magnification Telescope magnification Topics

2. Modern Optics Lab Lab 3: Experiments with the Telemicroscope Quantity Sign +- soso Real objectVirtual object sisi Real imageVirtual image f Converging lensDiverging lens yoyo Erect objectInverted object yiyi Erect imageInverted image FoFo FiFi f xoxo soso f sisi xixi yoyo yiyi Thin Lens

3. Modern Optics Lab Lab 3: Experiments with the Telemicroscope Measuring focal length of converging lens  Object at “infinity”  Image appears at focal point  Object at s o  Image at s i  Use lens formula to get f Lamp at front desk Lens Screen: Image of lamp LensReticule Your lamp from optics set in metal holder Screen: Image of reticule

4. Modern Optics Lab Lab 3: Experiments with the Telemicroscope The Magnifying Glass dodo uu yoyo soso sisi aa l L F Eye yiyi yoyo

5. Modern Optics Lab Lab 3: Experiments with the Telemicroscope The Magnifying Glass soso sisi aa l L F Eye yiyi yoyo

6. Modern Optics Lab Lab 3: Experiments with the Telemicroscope The Magnifying Glass Special Cases:  Eye as close as possible to the lens to maximize M p :  Relaxed Viewing:

7. Modern Optics Lab Lab 3: Experiments with the Telemicroscope Measuring Magnification of Magnifying Glass Move the reticule so it is in focus. Compare the size of the reticule spacing (1mm) seen through the lens with the size of the graph paper on the screen (seen simultaneously with the other eye and not through the lens). See next page for illustration. your eye (close to lens)  25 cm linear graph paper Lens Reticule f Stage Mount

8. Modern Optics Lab Lab 3: Experiments with the Telemicroscope Reticule 1mm spacing seen through lens Compare: 3.5 divisions on the graph paper taped to the screen = 1 division on the Reticule spacing seen through the lens.  M=3.5 (in this example) Graph paper 1mm spacing 25 cm away from eye: seen directly

9. Modern Optics Lab Lab 3: Experiments with the Telemicroscope The Compound Microscope soso sisi F Eye yiyi yoyo F xixi fofo fefe Virtual image at infinity when adjusted for relaxed viewing Eyepiece Objective

10. Modern Optics Lab Lab 3: Experiments with the Telemicroscope Setting up the Microscope Part 1: Getting s i, s o and thus M o Move lens A back/forth until you get a sharp image of reticule on the screen Determine s i and s o and calculate M o.  5 cm Stage mount with screen Reticule Lens A (Objective) Lamp  23 cm

11. Modern Optics Lab Lab 3: Experiments with the Telemicroscope Setting up the Microscope Part 2: Add eyepiece Insert lens B, remove stage mount. Adjust lens B until you see a sharp reticule through the microscope. Knowing f e compute the total magnification of the microscope. Stage mount with screen used to be here (remove) Reticule Lens A (Objective) Lamp Lens B (Eyepiece) fefe your eye (close to lens)

12. Modern Optics Lab Lab 3: Experiments with the Telemicroscope Setting up the Microscope Part 3: Measure Magnification Compare the size of the reticule spacing (1mm) seen through the microscope with the size of the graph paper on the screen (seen simultaneously with the other eye and not through the lens). Reticule Lens A (Objective) Lamp Lens B (Eyepiece) your eye (close to lens) Graph paper for comparison  25 cm

13. Modern Optics Lab Lab 3: Experiments with the Telemicroscope Building a Measuring Microscope Leave lens A and B where they are. Adjust object and reticule position until they are both in focus. Reticule is now where the first real image appears  Both reticule and image of object can be seen in focus and compared to each other. Careful when determining the size of the unknown object: o Reticule only experiences eyepiece magnification. o Object experiences eyepiece AND objective magnification. Stage mount with screen used to be here (replace with Reticule). Move until in focus Reticule used to be here (replace with stage mount and “unknown object” obtained from TA). Move object until it is in focus. Lens A (Objective) Lens B (Eyepiece) fefe your eye (close to lens)

14. Modern Optics Lab Lab 3: Experiments with the Telemicroscope Astronomical Telescope: Viewing Objects at Infinity eye s i  f o s o   (looking at far away objects) objective eyepiece virtual image  f e  f o + f e

15. Modern Optics Lab Lab 3: Experiments with the Telemicroscope Astronomical Telescope: Magnification s i  f o from virtual image  f e fofo yoyo yiyi uu aa

16. Modern Optics Lab Lab 3: Experiments with the Telemicroscope Setting up the Telescope and Measuring Magnification Look at scale with one eye through telescope and with the other eye directly. Compare the line spacing to determine magnification. Scale on white board at the front of the room Lens D (Objective) Lens E (Eyepiece) your eye  f D +f E lamp

17. Modern Optics Lab Lab 3: Experiments with the Telemicroscope What you should see white board Compare scale seen through telescope with scale seen directly to determine M. Here: Magnification looks like M  2.3 telescope eyepiece

18. Modern Optics Lab Lab 3: Experiments with the Telemicroscope Astronomical Telescope: Measuring the Entrance Pupil Entrance pupil = diameter of objective lens = d entrance Objective Lens Eyepiece Lens

19. Modern Optics Lab Lab 3: Experiments with the Telemicroscope Astronomical Telescope: Measuring the Exit Pupil (Use a screen to capture a sharp image of the objective lens) Exit pupil = diameter of focused image of objective lens = d exit Objective Lens Eyepiece Lens Diffuse Light