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 D 2, 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. Collection: Telescopes 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

25. William HerschelCaroline Herschel

26. Herschel 40 ft Telescope

27. Optical Reflecting Telescopes 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

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

51. Pu`u Poliahu UH 0.6-m UH 2.2-m The first telescopes on Mauna Kea (1964-1970)

52. Local Seeing Flow Pattern Around a Building Incoming neutral flow should enter the building to contribute to flushing, the height of the turbulent ground layer determines the minimum height of the apertures. Thermal exchanges with the ground by re- circulation inside the cavity zone is the main source of thermal turbulence in the wake.

53. Mirror Seeing When a mirror is warmer that the air in an undisturbed enclosure, a convective equilibrium (full cascade) is reached after 10-15mn. The limit on the convective cell size is set by the mirror diameter

54. LOCAL TURBULENCE Mirror Seeing The warm mirror seeing varies slowly with the thickness of the convective layer: reduce height by 3 orders of magnitude to divide mirror seeing by 4, from 0.5 to 0.12 arcsec/K The contribution to seeing due to turbulence over the mirror is given by:

55. Mirror Seeing When a mirror is warmer that the air in a flushed enclosure, the convective cells cannot reach equilibrium. The flushing velocity must be large enough so as to decrease significantly (down to 10-30cm) the thickness turbulence over the whole diameter of the mirror. The thickness of the boundary layer over a flat plate increases with the distance to the edge in the and with the flow velocity.

56. Thermal Emission Analysis VLT Unit Telescope UT3 Enclosure 19 Feb. 1999 0h34 Local Time Wind summit: ENE, 4m/s Air Temp summit: 13.8C

58. Gemini South Dome

73. Night Sky Emission Lines at Optical Wavelengths

74. Sky Background in J, H, and K Bands

75. Sky Background in L and M Band

76. V-band sky brightness variations

77. H-band OH Emission Lines

80. Camera Construction Techniques 1. Pre-amplifier Pressure Vessel Vacuum pump port Liquid Nitrogen fill port Camera mounting Face-plate. The photo below shows a scientific CCD camera in use at the Isaac Newton Group. It is approximately 50cm long, weighs about 10Kg and contains a single cryogenically cooled CCD. The camera is general purpose detector with a universal face-plate for attachment to various telescope ports. Mounting clamp

81. Camera Construction Techniques 4.... A cutaway diagram of the same camera is shown below. Thermally Electrical feed-through Vacuum Space Pressure vessel Pump Port Insulating Pillars Focal Plane of Telescope Telescope beam Optical window CCD CCD Mounting Block Thermal coupling Nitrogen can Activated charcoal ‘Getter’ Boil-off Face-plate

82. Camera Construction Techniques 5. CCD Temperature servo circuit board Platinum resistance thermometer Gold plated copper mounting block Top of LN2 can Pressure Vessel Signal wires to CCD Location points (x3) for insulating pillars that reference the CCD to the camera face-plate Aluminised Mylar sheet Retaining clamp The camera with the face-plate removed is shown below ‘Spider’. The CCD mounting block is stood off from the spider using insulating pillars.

83. Camera Construction Techniques 6. A ‘Radiation Shield’ is then screwed down onto the spider, covering the cold components but not obstructing the CCD view. This shield is highly polished and cooled to an intermediate temperature by a copper braid that connects it to the LN2 can. Radiation Shield

84. Camera Construction Techniques 7. ‘Spider’ Vane CCD Clamp plate CCD Signal connector (x3) Copper rod or ‘cold finger’ used to cool the CCD. It is connected to an LN2 can. Gold plated copper CCD mounting block. CCD Package Some CCDs cameras are embedded into optical instruments as dedicated detectors. The CCD shown below is mounted in a spider assembly and placed at the focus of a Schmidt camera. FOS 1 Spectrograph