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

2. Anatomy and Detection Characteristics
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. 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

26. William Herschel
Caroline Herschel

27. Herschel 40 ft Telescope

28. 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

29. Mirror Grinding Tool

30. Mirror Polishing Machine

31. Fine Ground Mirror

32. Mirror Polishing

33. Figuring the Asphere

39. Crossley 36” Reflector

40. Yerkes 40-inch Refractor

41. Drawing of the Moon
(1865)

42. First Photograph of the Moon (1865)

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

44. Diffraction

45. Wavefront Description of Optical System

46. Wavefronts of Two Well Separated Stars

47. When are Two Wavefront Distinguishable ?

48. Atmospheric Turbulence

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

50. Modern Observatories
The VLT Observatory at Paranal, Chile

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

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

54. 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.

55. 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

56. LOCAL TURBULENCE Mirror Seeing
The contribution to seeing due to turbulence over the mirror is given by:
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

57. Mirror Seeing
The thickness of the boundary layer over a flat plate increases with the distance to the edge in the and with the flow velocity.
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.

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

60. Gemini South Dome

62. Coating - thermal properties

63. Enclosure coatings UKIRT - reflective bare aluminum
UH - TiO2-based white paint
GEMINI - Al-based Lo-Mit paint
CFHT - TiO2-based white paint
IRTF - reflective aluminum foil
KECK - TiO2-based white paint
SUBARU - - reflective Alclad siding

64. CFHT
Keck
UKIRT
IfA
IRTF
Gemini
Subaru

65. Coatings tested red metal primer ACE
CFHT white paint Triangle Paint Co.
Gemini aluminum paint Lo-Mit
IRTF Al foil – 3.1mil 3M product # 439
light blue acrylic latex ACE color 24-D
dark blue acrylic latex ACE color 24-B

66. White
Al foil
Lo-Mit
Primer

67. Solar spectrum

70. Coatings - conclusions
Paints
all paints supercool at night by radiating to the sky
white paint heats the least in sunlight
pigmented paints heat more than white during the day
Reflective coatings
ideal thermal properties
heat very little during the day
hardly supercool at all at night

72. Conclusions:
Curved surfaces remain visible over wide areas regardless of whether they are painted or reflective, and are therefore difficult to hide.
Flat panels CAN produce very bright glares, but only in very specific directions. Outside these directions a panel will reflects blue sky.
The reflection of sunlight from cylindrical reflecting surfaces is much brighter than from spherical surfaces of similar size.
White domes and reflective domes in direct sunlight are equally bright, but reflective domes are visible much longer

73. Sunset on Mauna Kea Keck I and Subaru September 20, 1999 5:42 p.m.

74. Conclusions:
Telescope enclosures with both low visibility and excellent thermal properties are possible
A promising approach:
highly reflective siding
vertical flat walls
active control of glare geometries
Domes - painted or reflective – are hard to hide
Reflective domes remain highly visible longer than painted domes

89. Night Sky Emission Lines at Optical Wavelengths

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

91. Sky Background in L and M Band

92. V-band sky brightness variations

93. J-band OH Emission Lines

94. H-band OH Emission Lines

95. K-band OH Emission Lines

100. Uncorrected

101. ADC Conceptual Design Linear ADC design
Variable prism separation provides correction
UV-to-near IR transmission requires fused silica optics
Nulled
Fully Open, Z=60

103. Corrector for 4m prime focus telescope
(parabolic mirror)
This corrector includes an atmospheric dispersion compensator
consisting of 2 counter-rotating lenses (doublet)