Wonders Of The Sky 2009 Eclipses
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Wonders Of The Sky 2009 Eclipses






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Wonders Of The Sky 2009 Eclipses Wonders Of The Sky 2009 Eclipses Presentation Transcript

  • Wonders of the Sky
  • Eclipses
  • Types of Eclipses
    • Solar: Eclipses of the Sun
      • Partial
      • Total
      • Annular
    • Lunar: Eclipses of the Moon
      • Partial
      • Total
    View slide
  • Solar Eclipses
    • Eclipses of the Sun
    • Alignment: Sun, Moon, Earth (new moon)
    • The moon’s shadow covers part of the earth’s surface
    • Last for just a few minutes, total phase often 3-7 minutes
    • Types :
      • Partial
      • Total
      • Annular
    View slide
  • Eclipse Geometry
  • Eclipse Map
    • Solar eclipses are only visible in specific areas of earth
    • Total Eclipse: Visible in “Path of Totality”
    • Partial Eclipses: Visible in red bands
    • On average, any location will receive a total eclipse every 400 years
    • [ Animation ]
  • Moon’s Shadow from Mir, 1999
  • Photosphere
    • Photosphere: The sun’s visible “surface”
    • A layer of heated gas
    • Sunspots are sometimes visible on the photosphere
    • [ current sun ]
  • SF Partial Eclipse
  • Partial Eclipse Phases
  • Eclipse Shadows Above: View of eclipse through a telescope, note the corresponding shadows (right)
  • June 1994 Eclipse
  • Bailey’s Beads
    • Bailey’s Beads resemble a string of pearls briefly visible along the edge of the eclipsed sun
    • Represent sunlight shining through valleys on the edge of the moon’s disk
    • Single bright “bead”, diamond ring effect
  • Diamond Ring Effect Last remaining bit of sun’s visible surface before totality
  • Totality
    • At totality, the sun is entirely covered by the moon’s disk
    • The corona, the sun’s outer atmosphere, becomes visible as a pearly crown
    • The sky becomes dark during totality, bright stars and planets are visible
  • Totality, Awesome
  • Chromosphere
    • The sun’s visible disk is the photosphere
    • Photosphere visible through thick clouds or a filtered telescope
    • Chromosphere is red atmospheric layer on the sun just above the chromosphere
    • Chromosphere is only visible briefly during total eclipses of the sun or through expensive solar filters
  • Chromosphere and Prominences
    • Prominences represent large segments of the chromosphere that can become detached from the sun
    • Most prominences are larger than the earth
  • Chromosphere & Inner Corona
  • Dark Noon
    • Totality Sky
      • Bright stars and planets visible
      • Horizon glows sunset colors, “360-Degree sunset”
      • Venus, left of eclipsed sun
  • 360-Degree “Sunset” An all-sky image during totality Note, “sunset” colors surround entire horizon
  • Eclipse Montage
    • Note partial phases before and after totality (center)
    • Sun imaged with solar filter, unfiltered at totality
  • Shadow Bands
    • Shimmery affect on ground noticed right before start of totality
    • Resembles flickering bands of light
    • Best seen on white surface (sheet)
    • Most likely due to bright, point like light source (diamond ring) distorted by atmospheric air flow
    Shadow bands, 1870 Italy
  • Shadow Band Animation
  • Shadow Band Still Image
  • Eclipse Safety
    • Caution :
      • Partial solar eclipses are not safe to observe with unaided eye
      • Total phase of a solar eclipse can be directly observed
      • Safe Sunwatching
      • Note : Eclipses of the moon are always safe to observe
    • Methods :
      • Eclipse glasses
      • Filtered telescopes
      • Projection
  • Safe-totality NOT safe- partial eclipses
  • Eclipse Glasses
    • Made from reflective mylar, designed especially for viewing the sun
    • Don’t use sunglasses, smoked glass, film negatives, etc. Not safe!
  • Solar Projection
    • Use a telescope to project the sun’s image onto a flat sheet
    • Don’t look into the eyepiece!
  • Again, Jones’s sneaky colleagues aimed the telescope at the sun…
  • Pinhole Projection
  • Eclipse Videos
    • Total Solar Eclipse - Egypt 2006
    • Totality Highlights: Total Solar Eclipse 2008: Live from China
    • Perfect Eclipse – Mexico, 1991
  • Annular Eclipse
    • “ Ring Eclipse”
    • Occurs when moon near apogee, smallest apparent disk
    • Moon’s disk not large enough to cover the sun completely
    • Unlike true total eclipses, not safe to observe without protection
  • Eclipse ‘94
  • Annular Geometry
  • Lunar Eclipses
    • Eclipses of the moon
    • Alignment: Sun, Earth, Moon (full moon)
    • The earth’s shadow covers part or all of the moon’s surface
    • About 4 hours for complete eclipse, totality can last for nearly an hour
    • Unlike solar eclipses, entire night side of earth can witness
    • Types :
      • Total
      • Partial
  • Lunar Eclipse
  • Total Lunar Eclipses
    • When eclipsed, the moon usually appears red
    • The earth’s shadow has some light directed into it by the edge of earth’s atmosphere
    • Similar to red sunset colors
    • Video
  • Lunar Eclipse Partial Stages
  • Eclipse ’04 Diagram
    • Earth’s shadow has two zones, umbra and penumbra
    • Moon passed through dark center of earth’s shadow (umbra) during totality
    • Partial eclipses when moon partly immersed in umbra
  • Eclipse ’04: Red Moon
  • Earth’s Shadow
  • Lunar Eclipses
    • Total : Moon passes completely into the earth’s inner shadow (umbra)
    • Partial : Moon passes partly into the umbra
    • Penumbral : Moon passes only into the earth’s outer shadow (penumbra)
  • Partial Eclipses: Impossible Lunar “Phases”
    • The moon’s regular phases never appear like this and the following photos
  • Partial Lunar Eclipse
  • Penumbral Eclipses
    • Not as dramatic, more difficult to see effect
    • Penumbra resembles a slightly darker shading on one half of the moon
    • Again, moon passes only through earth’s outer shadow, not the darker umbra in center
  • Total Lunar Eclipse Dark Sky
    • During a total eclipse of the moon, a bright, full moon-lit sky becomes much darker during totality
    • Dimmer stars appear, even the Milky Way and dim celestial objects can be seen
  • Full Moon Night
  • Next Eclipses
    • Solar
      • America, 2017
    • Lunar
      • Dec, 2010