Unified Astronomy Thesaurus

  1. O associations
  2. O clusters
  3. O dwarfs
  4. O giant stars
  5. O magnitude
  6. O stars
  7. O subdwarfs
  8. O supergiants
  9. O-association USE O associations
  10. O-clusters USE O clusters
  11. O-type main sequence stars USE O stars
  12. O-type stars USE O stars
  13. OB associations
  14. OB stars
  15. OB supergiants
  16. Oberon USE Uranian satellites
  17. Oblateness
  18. Oblique rotators
  19. Obliquity USE Axial tilt
  20. Obliquity of ecliptic
  21. Obliquity of the ecliptic USE Obliquity of ecliptic
  22. Observation techniques
  23. Observational astronomy
  24. Observational cosmology
  25. Observatories
  26. Occultation
  27. Occulting discs USE Occulting disks
  28. Occulting disks
  29. Ocean planets
  30. Ocean tides
  31. Ocean-atmosphere interactions
  32. OCOs USE Oort cloud objects
  33. Oe stars
  34. Oef stars
  35. Of stars
  36. Of type stars USE Of stars
  37. Of-type stars USE Of stars
  38. OH clouds USE Hydroxyl radical clouds
  39. OH masers USE Hydroxyl masers
  40. OH sources USE Hydroxyl sources
  41. OH-IR stars USE OH/IR stars
  42. OH/IR stars
  43. Old stars
  44. Omega baryons
  45. Omega lambda
  46. Omega mass
  47. Omega parameter
  48. Omega( lambda) USE Omega lambda
  49. Omega(baryon) USE Omega baryons
  50. Omega(mass) USE Omega mass
  51. Omicron ceti stars USE Mira variable stars
  52. ONC population USE Orion population stars
  53. ONC stellar population USE Orion population stars
  54. Oort Cloud USE Oort cloud
  55. Oort cloud
  56. Oort cloud objects
  57. Oort constants
  58. Oort formulae
  59. Oort formulas USE Oort formulae
  60. Oort's formulae USE Oort formulae
  61. Oort's formulas USE Oort formulae
  62. Oosterhoff groups
  63. Open clusters USE Open star clusters
  64. Open star clusters
  65. Open universe
  66. Öpik theory USE Opik theory
  67. Opik theory
  68. Öpik's theory USE Opik theory
  69. Opik's theory USE Opik theory
  70. Opik-Oort Cloud USE Oort cloud
  71. Öpik–Oort cloud USE Oort cloud
  72. Opposition
  73. Opposition (astronomy) USE Positional astronomy
  74. Optical bursts
  75. Optical counterparts USE Optical identification
  76. Optical double stars USE Optical doubles
  77. Optical doubles
  78. Optical flares
  79. Optical identification
  80. Optical interferometry
  81. Optical observation
  82. Optical observatories
  83. Optical outbursts USE Optical bursts
  84. Optical phase shifting interferometry
  85. Optical phase-shifting interferometry USE Optical phase shifting interferometry
  86. Optical position
  87. Optical pulsars
  88. Optical telescopes
  89. Orbit determination
  90. Orbit dynamics USE Orbital dynamics
  91. Orbital anomalies
  92. Orbital dynamics
  93. Orbital elements
  94. Orbital evolution
  95. Orbital mechanics USE Astrodynamics
  96. Orbital motion
  97. Orbital nodes
  98. Orbital resonance gaps
  99. Orbital theory
  100. Orbiting observatory USE Space observatories
  101. Orbits
  102. Orcus
  103. Orientation
  104. Origin of the Milky Way USE Milky Way formation
  105. Origin of the universe
  106. Orion Nebula population stars USE Orion population stars
  107. Orion population USE Orion population stars
  108. Orion population stars
  109. Orphan planets USE Rogue planets
  110. Orreries
  111. Oscillating universe
  112. Osculating orbit
  113. Osculatory elements
  114. Our galaxy USE Milky Way Galaxy
  115. Outbursts USE Optical bursts
  116. Outer planets
  117. Overabundance
  118. Oxygen burning
  119. Ozone layer