1. History of Astronomical Instruments The early history: From the unaided eye to telescopes

2. The Human Eye Anatomy and Detection Characteristics

3. Anatomy of the Human Eye

14. Visual Observations • Navigation • Calendars • Unusual Objects (comets etc.)

16. Hawaiian Navigation: From Tahiti to Hawaii Using the North direction, Knowledge of the lattitude, And the predominant direction of the Trade Winds

17. Tycho Quadrant

19. Pre-Telescopic Observations • Navigation • Calendar • Astrology • Planetary Motion • Copernican System • Kepler’s Laws

21. Why build telescopes? • Larger aperture means more light gathering power • sensitivity goes like D2, where D is diameter of main light collecting element (e.g., primary mirror) • Larger aperture means better angular resolution • resolution goes like lambda/D, where lambda is wavelength and D is diameter of mirror

22. Refractor telescopes exclusively use lenses to collect light have big disadvantages: aberrations & sheer weight of lenses Reflector telescopes use mirrors to collect light relatively free of aberrations mirror fabrication techniques steadily improving Collection: Telescopes

25. William Herschel Caroline Herschel

26. Herschel 40 ft Telescope

27. Basic optical designs: Prime focus: light is brought to focus by primary mirror, without further deflection Newtonian: use flat, diagonal secondary mirror to deflect light out side of tube Cassegrain: use convex secondary mirror to reflect light back through hole in primary Nasmyth focus: use tertiary mirror to redirect light to external instruments Optical Reflecting Telescopes

28. Mirror Grinding Tool

29. Mirror Polishing Machine

30. Fine Ground Mirror

31. Mirror Polishing

32. Figuring the Asphere

38. Crossley 36” Reflector

39. Yerkes 40-inch Refractor

40. Drawing of the Moon (1865)

41. First Photograph of the Moon (1865)

42. The Limitations of Ground-based Observations Diffraction Seeing Sky Backgrounds

43. Diffraction

44. Wavefront Description of Optical System

45. Wavefronts of Two Well Separated Stars

46. When are Two Wavefront Distinguishable ?

47. Atmospheric Turbulence

48. Characteristics of Good Sites • Geographic latitude 15° - 35° • Near the coast or isolated mountain • Away from large cities • High mountain • Reasonable logistics

49. Modern Observatories The ESO-VLT Observatory at Paranal, Chile