Successfully reported this slideshow.
Wonders of the Sky
Wonders of the Darkening Sky (The Twilight Period)
Twilight <ul><li>The period of darkening sky is also termed twilight </li></ul><ul><li>Twilight is an effect created by th...
Earthshine http://www.spaceweather.com/swpod2006/03jan06/laveder.jpg
Crescent Moon, Earthshine “ Old moon in the new moon’s arms”
Earthshine Explanation <ul><li>Earthshine : When the dark surface of the moon glows faintly from light reflected from eart...
Ultimate Earthshine March 2006 Total Eclipse
Young, Old Moons <ul><li>The thin crescent moon, just after new moon, is often known as a  young moon </li></ul><ul><li>A ...
Young Moon, Old Moon Young crescent moon in evening sky Old crescent moon in morning sky
 
Dickens : Barnaby Rudge, 1841 <ul><li>“ It was a fine dry night, and the light of a young moon, which was then just rising...
Young Moon & Pleiades
Inferior Planets <ul><li>Mercury & Venus </li></ul><ul><li>Inferior planets : Between earth and sun </li></ul><ul><li>Visi...
Where’s Mercury? http://www.spaceweather.com/swpod2006/25feb06/vsoske.jpg
Moon and Venus
Moon and Venus Conjunction
Venus Corona Venus is so bright, it can form a corona similar to the moon and sun
June 1991 Conjunction of Mars, Venus, and Jupiter http://www.stargazing.net/drsmith/vmj91a.jpg Planets can often be seen t...
April 23, 1998: Moon, Venus, Jupiter <ul><li>Venus & Jupiter often appear close together creating impressive conjunctions ...
Conjunction of Naked-Eye Planets
Venus, not “UFO” <ul><li>The planet Venus resembles a very bright star when seen in the evening sky </li></ul><ul><li>Venu...
Satellites: “Moving Stars” <ul><li>Since the 1957 launch of Sputnik, the sky is full of  satellites </li></ul><ul><li>Sate...
Satellite Visibility A: Daylight, satellite not visible B: Twilight, satellite visible C: Night, satellite within earth’s ...
Satellite Tracking This view of the International Space Station was taken through a telescope equipped with a tracking com...
Noctilucent Clouds <ul><li>Noctilucent clouds  are clouds that remain visible in a dark sky, resemble silvery cirrus cloud...
Noctilucent Clouds http://antwrp.gsfc.nasa.gov/apod/image/0306/noctilucent_pp_big.gif
NLCs
NLCs in London London, June 23, 1996
NLCs from ISS
Upcoming SlideShare
Loading in …5
×

Wonders Of The Sky 2009 Darkening Sky

447 views

Published on

Published in: Technology, Education
  • Be the first to comment

  • Be the first to like this

Wonders Of The Sky 2009 Darkening Sky

  1. 1. Wonders of the Sky
  2. 2. Wonders of the Darkening Sky (The Twilight Period)
  3. 3. Twilight <ul><li>The period of darkening sky is also termed twilight </li></ul><ul><li>Twilight is an effect created by the atmosphere </li></ul><ul><li>If we had no atmosphere, the sky would be instantly black at sunset </li></ul>
  4. 4. Earthshine http://www.spaceweather.com/swpod2006/03jan06/laveder.jpg
  5. 5. Crescent Moon, Earthshine “ Old moon in the new moon’s arms”
  6. 6. Earthshine Explanation <ul><li>Earthshine : When the dark surface of the moon glows faintly from light reflected from earth </li></ul><ul><li>Earthshine resembles a faint full moon held by the thin crescent moon </li></ul><ul><li>“ Old moon in the new moon’s arms” </li></ul>At C, an observer would see light from the sun, reflected by the earth, and then reflected back by the moon!
  7. 7. Ultimate Earthshine March 2006 Total Eclipse
  8. 8. Young, Old Moons <ul><li>The thin crescent moon, just after new moon, is often known as a young moon </li></ul><ul><li>A morning crescent, just before new moon, is an old moon </li></ul><ul><li>Young moons-early evening; OId moons, early morning </li></ul><ul><li>Young moons are easiest to seen in the spring </li></ul>
  9. 9. Young Moon, Old Moon Young crescent moon in evening sky Old crescent moon in morning sky
  10. 11. Dickens : Barnaby Rudge, 1841 <ul><li>“ It was a fine dry night, and the light of a young moon, which was then just rising, shed around that peace and tranquillity which gives to evening time its most delicious charm.” </li></ul><ul><li>Barnaby Rudge, published 1841 </li></ul>
  11. 12. Young Moon & Pleiades
  12. 13. Inferior Planets <ul><li>Mercury & Venus </li></ul><ul><li>Inferior planets : Between earth and sun </li></ul><ul><li>Visible : </li></ul><ul><ul><li>After sunset, or before sunrise </li></ul></ul><ul><ul><li>Twilight and early evening only, or twilight and late morning </li></ul></ul><ul><li>Mercury is visible for about two weeks at a time, Venus is visible for about 9 months at a time </li></ul><ul><li>An appearance of Mercury or Venus is termed an apparition </li></ul>
  13. 14. Where’s Mercury? http://www.spaceweather.com/swpod2006/25feb06/vsoske.jpg
  14. 15. Moon and Venus
  15. 16. Moon and Venus Conjunction
  16. 17. Venus Corona Venus is so bright, it can form a corona similar to the moon and sun
  17. 18. June 1991 Conjunction of Mars, Venus, and Jupiter http://www.stargazing.net/drsmith/vmj91a.jpg Planets can often be seen to form groups or conjunctions
  18. 19. April 23, 1998: Moon, Venus, Jupiter <ul><li>Venus & Jupiter often appear close together creating impressive conjunctions </li></ul>
  19. 20. Conjunction of Naked-Eye Planets
  20. 21. Venus, not “UFO” <ul><li>The planet Venus resembles a very bright star when seen in the evening sky </li></ul><ul><li>Venus has often been reported as a “UFO” (President Jimmy Carter in 1969) </li></ul>Venus over San Francisco
  21. 22. Satellites: “Moving Stars” <ul><li>Since the 1957 launch of Sputnik, the sky is full of satellites </li></ul><ul><li>Satellites resemble moving stars </li></ul><ul><li>Most seen up to 90 minutes before or after sunset </li></ul>http://satobs.org/image/trail.jpg
  22. 23. Satellite Visibility A: Daylight, satellite not visible B: Twilight, satellite visible C: Night, satellite within earth’s shadow and not visible
  23. 24. Satellite Tracking This view of the International Space Station was taken through a telescope equipped with a tracking computer http://www.heavenscape.com/iss.gif
  24. 25. Noctilucent Clouds <ul><li>Noctilucent clouds are clouds that remain visible in a dark sky, resemble silvery cirrus clouds </li></ul><ul><li>They are the highest visible clouds in the atmosphere, located above the stratosphere </li></ul><ul><li>Noctilucent means “night glowing” </li></ul><ul><li>Only visible from high latitudes (45-60 ° north) around the summer solstice (June 21) </li></ul><ul><li>Animation : http://svs.gsfc.nasa.gov/goto?10002 </li></ul>
  25. 26. Noctilucent Clouds http://antwrp.gsfc.nasa.gov/apod/image/0306/noctilucent_pp_big.gif
  26. 27. NLCs
  27. 28. NLCs in London London, June 23, 1996
  28. 29. NLCs from ISS

×