1. Greatest Eastern Elongation
    For planets inside Earth's orbit, it is the furthest angular separation from the earth east of the sun.
  2. Superior Conjunction
    Planet is opposite earth on the other side of the sun.Image Upload 1
  3. Inferior Conjunction
    When two planets are aligned on the same side of the sun.Image Upload 2
  4. Precession of the moon's orbit is _________ when viewed north of the ecliptic plane.
  5. Moon's Orbital Precession Period
    18.61 years
  6. Noncentral Solar Eclipses
    ...are partial eclipses.

    You can't see a full eclipse no matter your location on earth.
  7. Annular or Ring Eclipse
    When the moon is smaller than the sun during an eclipse.
  8. Who had the first model of the solar system?
  9. Full moon is how much brighter than a 1st or 3rd quarter moon?
    11x brighter
  10. Define: Albedo
    Fraction of light reflected by surface
  11. Planetary Opposition
    Image Upload 3 ONLY with Superior Planets
  12. For transit to occur...
    Planet must be at node of it's orbit and at inferior conjunction
  13. Define: Transit
    • When a planet covers a spot of sun
    • ONLY with inferior planets
  14. Superior Planets
    lie exterior to Earth's orbit
  15. Inferior Planets
    lie interior of Earth's orbit
  16. Planets approximately follow...
    the ecliptic
  17. Anomalistic Month Period
    • time for moon to return to perigee or apogee
    • = ~27.55 days
  18. Eclipse Year
    • time it takes for a lunar node to return to its original alignment with respect to the sun
    • = ~346.62 days
  19. Eclipse Half-Year
    • time between eclipse seasons
    • = ~173.31 days
    • = 6 lunations - 4 days
  20. How long is the period of precession of the moon's orbit?
    ~18.61 years
  21. Conditions for an Eclipse
    • Moon must be full or new
    • Sun must be within +/-15 degrees of a node on the line of node
    • Moon must be within 1 degree of ecliptic
  22. Sun and moon move ______ relative to the stars
  23. Apogee
  24. Perigee
  25. Hubble's Law
    • Light from star receding is red-shifted
    • Light from star approaching is blue-shifted

    SO universe is expanding
  26. One total eclispse every...
    11/2 years
  27. Arcsecond
    Second of arc = 1/60 arcminute = 1/3600 degree
  28. Arcminute
    Minute of arc = 1/60 degree
  29. Size of Moon
    compared to
    Size of Sun
    1 : 400
  30. Distance to Moon
    compared to
    Distance to Sun
    1 : 400
  31. Total Lunar Eclipse
    Moon passes entirely through umbra
  32. Partial Lunar Eclipse
    OR "partial umbra eclipse"

    Part of moon passes through umbra
  33. Penumbral Lunar Eclipse
    Moon passes through penumbra
  34. Types of Lunar Eclipses
    • Penumbral Lunar Eclipse
    • Partial Lunar Eclipse
    • Total Lunar Eclipse
  35. Umbra's diameter?
    1.5 degree
  36. How big are the umbra and penumbra relative to each other?
    • Umbra is exactly one-half radius of penumbra
    • Image Upload 4
  37. Which is penumbra? umbra?
    Image Upload 5
  38. Moon moves ______ in one hour
    through its own diameter
  39. How many degrees does moon move around the earth in an hour? a day? a year?
    • Hour: ~1/2 degrees
    • Day: ~13.2 degrees
    • Year: 360 degrees
  40. Earth moves how many degrees around the sun each day?
    ~1 degree
  41. Moon's Sidereal Period
    OR Orbital Period

    Time for the moon to return to given star on the celestial sphere

    ~271/3 days
  42. When a planetary body culminates, what happens?
    It is on the meridian.
  43. Distance to the moon is what?
    30 +/- 2 Earth diameters
  44. 1st quarter Moon is at...
    East Quadrature
  45. 3rd quarter moon is at...
    West Quadrature
  46. The moon at opposition is...
  47. A full moon is at...
  48. The moon at conjunction is...
  49. The new moon is at...
  50. Lunation=
    • = 291/2 days
    • = Synodic Period = Phase Period
  51. Synodic Period
    time required for a planetary body to return to the same position relative to the sun


    time taken for object to completely orbit around another
  52. Moon
    Synodic Period=
    • =Lunation = Phase Period
    • =291/2 days
  53. Terminator
    Image Upload 6
  54. Diameter of Moon
    1/4(Diameter of Earth)
  55. Define:
    Tropical Year
    • or "Seasonal Year"
    • Time for sun to return to vernal equinox position
    • =365.242 days
  56. Four Major Celestial Days
    Image Upload 7
  57. 3 Pacesetters for Glaciation
    • 1) Eccentricity of Earth's orbit
    • 2) Tilt of Earth's spin axis (22.25-24.5 degrees)
    • 3) Precession of Earth's spin axis
  58. Eccentricity of earth's orbit is over period of...
    100,000 years
  59. Which way does Earth's spin axis precess?
    • clockwise
    • Image Upload 8
  60. Define:
    Precession of Earth's Spin Axis
    • the axis changes its angle relative to the sun
    • Image Upload 9
  61. Precession Period of Earth's spin axis
    25,800 years
  62. What are cross quarter days?
    The days in between the solstices and equinoxes:

    • Lughnasa
    • Samhain
    • Imbolc
    • Beltzine
  63. Saros Cycle
    • =18 years 11 days
    • 234 Anomalistic Months
    • time it takes for sun, earth, and moon to return to approximatey the same relative geometry
    • nearly identical eclipses
  64. Best time to see Venus is when...
    it's at the farthest angular distance from the sun
  65. Quadrature
    when the superior planets are 90 degrees from the sun at the Earth
  66. Sidereal Period for Planets
    time to orbit the sun relative to the fixed stars
  67. Synodic Period for Planets
    • time for planet to repeat its configurations (opposition-opposition)
    • "Configuration period"
  68. What is the order of: opposition, conjunction, east quadrature, west quadrature?
    W.Q., Opposition, E.Q., Conjunction
  69. Who figured out that the planets' orbits are elipses?
    Johannes Kepler
  70. Best time to look at superior planets?
    When its at opposition
  71. Why is the best time to look at a superior planet when it's at opposition?
    • it's close
    • it's brighter
    • convenienet because on the meridian at minight
    • rises sunset, sets at sunrise
  72. Retrograde Motion
    When the planet stops and moves westward relative to the stars
  73. Direct or Prograde Motion
    Planet moves eastward toward larger right ascensions relative to stars
Card Set
Astronomy Study T2