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Heavenly shadows


I created and shared this presentation about Solar Eclipses at the Annual IPS-NYP Astronomy Retreat at Nongsa Point on Batam in 2011.

I created and shared this presentation about Solar Eclipses at the Annual IPS-NYP Astronomy Retreat at Nongsa Point on Batam in 2011.

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  • 1. by Koh Joo Beng
  • 2. Overview• The Sun• History of Eclipses• Geometry• Observing• Phases• Oddities• Videos/Slideshows• Upcoming Eclipses• Resources
  • 3. The SunVolume: 1,300,000 EarthsMass: 333,000 EarthsPower: 4 x 1026 W(50,000 billion reactors)0.0005 % reaches Earth
  • 4. “Parts” of the Sun
  • 5. CME!7 Jun 2011
  • 6. Photon’s “walk”• Photon (initially gamma ray) is created by thermonuclear fusion• Reaches convective region only after 20,000~100,000 yrs!• Collides with others along the way and loses energy to become visible light photon• Radiates away at the surface of the Sun• Takes only 8 minutes to get to Earth
  • 7. Brief History of Eclipses
  • 8. Geometry of EclipsesNot to Scale!
  • 9. Types of Solar Eclipses • Total or Annular? Is due to the elliptical orbit of the Moon (and also the Earth) – Moon at apogee = Annular Eclipse.Not to Scale! – At perigee = Total Eclipse • Total Eclipse over a particular city is once in 370 years! Total Annular Partial
  • 10. A Coincidence?• Sun is 400 times larger than the Moon• Sun is 400 times farther than the Moon• Both objects subtend angle of 0.5 degrees!• Is physics involved? Or just pure luck?• Moon is receeding 4cm/yr.• 100 million years ago, no annular eclipses• 100 million years later, no more total eclipses!• Can’t see a total eclipse on any other planet.
  • 11. Why not 13 eclipses a year?• On Youtube at• Or search Youtube for “Solar Eclipse Educational Video”• Or click here.
  • 12. Observing an Eclipse Never look directly at the Sun, Except DURING especially with a moment of telescope TOTAL ECLIPSE Instant and irreparable eye damage can occur.
  • 13. Observing phases of an Eclipse Shade 14 Welder’s glass
  • 14. Phases of a Total Eclipse• 4 “Contacts” depending on which “limb” or edge of Moon-Sun is in contact. 1st Contact 2nd Contact 3rd Contact 4th Contact
  • 15. Diamond Rings & Bailey’s Beads• Possible to see only at 2nd and 3rd contact
  • 16. Oddities
  • 17. The Corona! 1/64 sec 2 sec Composite
  • 18. Videos/Slideshows
  • 19. China Total Eclipse 2008• On Youtube at• Or search Youtube for “Joo Beng’s Total Solar Eclipse 2008”• Or click here.
  • 20. Slideshows• Kenya 2010• South America 2010
  • 21. Annular Eclipse Kenya 2010
  • 22. Easter Island Total Eclipse 2010• On Youtube at• Or search Youtube for “Easter Island Solar Eclipse 2010”• Or click here.
  • 23. Coming Solar Eclipses• 2011 – 1 Jul : Partial Eclipse – Antarctica – 25 Nov: Partial Eclipse – Antarctica• 2012 – 20 May : Annular Eclipse – USA-Japan-Fuzhou – 13 Nov : Total Eclipse – Pacific-Australia (Cairns)• 2013 – 10 May : Annular Eclipse – Pacific-Australia – 3 Nov : Hybrid Eclipse – Africa
  • 24. Total Eclipse 13 Nov 2012
  • 25. Eclipse Resources• : – Ultimate resources for eclipses• NASA Eclipse website : – For lots of Technical Data• Java Solar Eclipse Explorer : – Calculator to determine eclipses viewable from Singapore (or any other city) – Previous Total Eclipse on 4 Mar 1821! – Next Annular Eclipse on 26 Dec 2019! – Next Total Eclipse on 5 Jul 2168!• Eclipse in a Different Light : – Eclipse stories, folklore
  • 26. Questions?
  • 27. Thank you!! If you have any questions, do send an email
  • 28. The End
  • 29. Backup material
  • 30. Do you want to know more about Astronomy?• Basics of Astronomy • Astronomy Equipment – Astronomical vocabulary, distance units, parsec, – Refractors, Reflectors, Cassegrains and other light year telescope designs – The motion of the planets, elliptical orbits, – Telescope mounting systems, Alt-Az vs Keppler’s laws. Equatorial. – Seasons, and why they occur, Earth’s tilt. – Astrophotography, Polar alignment, Focusing in – The Lunar Cycle the dark, CCD, Image processing – Eclipses, how they occur, differences between – Telescopes in Space, Hubble, Chandra. Lunar and Solar eclipses – Large telescopes of the World, Keck, VLSI, VLT, – Local coordinates, Celestial coordinates, Galactic ELT, coordinates, • Solar system overview and Birth Theory. – Newton ’s Laws – Earth – Nature of light – The Moon• History of Astronomy – The Sun as a star. – The Scientific Method – Mercury, Venus, Mars – Ancient astronomers, Galileo, Copernicus, Tycho – Jupiter, Saturn, Uranus, Neptune Brahe – Pluto, discussion of Pluto being a minor planet. – Archaeastronomy – Comets and asteroids, Meteorites.• Intermediate Astronomy • Cosmology – Colour of Stars, Relationship of Colour to – The Big Bang, Big Crunch temperature – Einstein’s Theory of Relativity, Special, General – Spectral lines and chemical composition – Relativistic Doppler Shift – The Inverse square law of brightness, H-R – Cosmological Constant Diagram – The Doppler effect – Hubble’s Law – Multi-wavelength astronomy, Radio, X-ray, – Expansion of the Universe Infrared, Gamma-ray. – Cosmic Microwave Background – Black Holes, Quasars and Active Galaxies, – COBE, WMAP Neutron stars, Pulsars, White Dwarfs • And much much more.... – Galaxies, The Milky Way
  • 31. To purchase your own telescopeor other astronomy-related equipment,visit
  • 32. Other useful links• Stellarium - Planetarium program• Celestia – Space Simulation• Singastro – Singapore’s astronomy forum• Singastro Wiki - Wiki for Astronomy Beginners in Singapore• – Singapore astronomy portal• Printable Sky Charts – Cartes du Ciel• Interactive Sky Charts – From Sky & Telescope : – Astronomy Magazine :
  • 33. Overview• Objective: Give audience an appreciation of the beauty of Sun, and share the • Phases of the eclipse thrill of a total solar eclipse • 1st to 4th contacts• Format : Slides, videos, with narration. Use Starry Night to show. Minimal • Diamond ring, Bailey’s Beads interaction. • Corona • Oddities of eclipses• Overview of Sun – parts of the Sun • Shadow bands – light through fluid. • Photosphere, Chromosphere, Corona – thin hot atmosphere of Sun. Shaped by • Solar crescents magnetic field. • Shadow racing from West to East • Prominences – plumes of gas, Sunspots, Filaments, • Twilight effect – setting sun colours. • How long it takes photon to emerge – solar walk • Videos of eclipses• Stories of eclipses • Mongolia • Dragon eating Sun • Easter Island • Sun-Moon lovers fighting • Kenya • Sun-Moon Lovers hiding in darkness • Coming eclipses • Sun angry, hiding for a while • Annular eclipse – May 2012, USA • 585BC – Central Turkey Meades and Linions, battle of 5 yrs, was predicted by • Total eclipse – Nov 2012, Fiji astronomers, but soldiers didn’t know. Eclipse was sign that they should not fight. Cemented bond with double marriage. • Solar eclipse resources • 1919 Evidence for General Theory of Relativity – Arthur Eddington, • Mr Eclipse – Fred Espenak• Geometry of eclipses • Eclipse path maps • Sized by chance? Moon receeding…4cm/yr. 100m yrs no more eclipses. 100m yrs • Total and annular path forecasts ago, no annulars. Can’t even see corona, so not as fun. No other planet can ever see a total eclipse (e.g. Mars moons too small, Jupiters too big) • Omitted: • New Moon. • Planning the eclipse • Partial, Annular vs Eclipse, Hybrid • Prioritize one feature to look at. • Orbit is elliptical – variation of Moon at Apogee (smaller) and Perigee (larger) • Earth’s orbit also elliptical • Don’t photograph • Hybrid eclipse – Annular-Total-Annular • Enjoy • Video – why eclipses don’t occur 13 times a year • Timing, practice practice practice. • Timing of eclipses – few seconds – max 7.5 min. Mostly 2min. • Solar photography/videography • 1 in 360 yrs eclipse is over a city. So have to travel to see it. • Built-up corona – insufficient dynamic range in cameras• Observing eclipses • Eclipse sequencing - photoshop • Warning - Power of the Sun. Do not look at the Sun without protection. Melted • Equipment eyepiece cap? • Zoom • Filters, not during totality • Camera • Always before the objective, never at the eyepiece. • Exposure settings • When telescopes pointed at Sun, must be attended. • Focus • Solar glasses • Creative eclipse photos • Shade 14 Welder’s glass • Name eclipse – Singapore? • Telescope projection - refractors • Pin-hole projection • • Sunspotter • Bucket of water?