1 / 25

The REAL OCCULT:

The REAL OCCULT:. Lunar & Solar Eclipses and Asteroid & Stellar Disappearances Sometimes Involving Luna By Dr. Harold Williams of Montgomery College Planetarium http://montgomerycollege.edu/Departments/planet/. Types of Occultations. Lunar Eclipse, Solar Eclipse,

chill
Download Presentation

The REAL OCCULT:

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The REAL OCCULT: Lunar & Solar Eclipses and Asteroid & Stellar Disappearances Sometimes Involving Luna By Dr. Harold Williams of Montgomery College Planetarium http://montgomerycollege.edu/Departments/planet/

  2. Types of Occultations • Lunar Eclipse, • Solar Eclipse, • Asteroidial Occultation, • Lunar Occultation, • Grazing Lunar Occultation • Planet Lunar Occultation • Transit of Planet across the Sun • Transit of Mercury (next one November 8, 2006) • Transit of Venus (June 8, 2004, next one June 6, 2012) • Planet disappearing behind moon

  3. Lunar Eclipse • Lunar Eclipse, shadow of the earth gets in front of the full moon at night time. • When the moon, earth, and sun align in that order at a node. • The reason we do not have 13 eclipses a year is because the orbit of the earth around the sun, the ecliptic, and the orbit of the moon around the earth are inclined by around 5 degrees, they are not aligned (it would be improbable if they were perfectly aligned instead of being close).

  4. A Total Lunar Eclipse (1)

  5. A Total Lunar Eclipse (2) A total lunar eclipse can last up to 1 hour and 40 min. During a total eclipse, the moon has a faint, red glow, reflecting sun light scattered in Earth’s atmosphere.

  6. Lunar Eclipses Earth’s shadow consists of a zone of partial shadow, the Penumbra, and a zone of full shadow, the Umbra. If the moon passes through Earth’s full shadow (Umbra), we see a lunar eclipse. If the entire surface of the moon enters the Umbra, the lunar eclipse is total.

  7. Solar Eclipse • Solar Eclipse, new moon gets in front of the sun in the day time. • When the earth, moon, and sun align in that order at a node. • The reason we do not have an eclipse every month is again, because of the 5 degree inclination of the orbit of the earth around the sun and the orbit of the moon around the earth. • Fred Espenak's Eclipse Pages at http:/sunearth.gsfc.nasa.gov/eclipse/eclipse.html, best general scientific source of eclipse maps, dates, and general data for both lunar and solar eclipses. Everyone uses Fred Espenak, he is without peer for specific eclipse information. • Wendy Carlos Eclipse Pages at http://www.wendycarlos.com/eclipse.html , some of the finest pictures taken by a true artist of solar eclipses and music.

  8. Diamond Ring Effect

  9. Solar Atmosphere Revealed

  10. Solar Eclipses The sun appears approx. as large in the sky (same angular diameter ~ 0.50) as the moon. When the moon passes in front of the sun, the moon can cover the sun completely, causing a total solar eclipse.

  11. Solar Eclise Viewing • While lunar eclipses are inherently safe, Solar Eclipses, the partial phases, are of course dangerous to human eyes. Of course, they are no more dangerous than looking at the sun on any day time that the sun is visible. Toddlers and grasshoppers avoid blinding themselves every day when the sun is visible by not looking directly at it. • If it hurts don't do it. • Safe Solar Filters

  12. Solar Filters Places to get safe solar filters • http://www.tropicalsails.com/shades.htm • http://www.eclipse1999.com/ • http://www.weatherman.com/ECLIPSE2000.htm • 301-482-0000 or 301-482-2210 Hands on Optics in Damascus, MD 20872, http://www.handsonoptics.com . During the total solar eclipse though it is quite safe to look directly at the sun. I have spent a total of 4 minutes looking directly at the sun during two total solar eclipses; and it has not damaged my eyes.

  13. Earth and Moon’s Orbits Are Slightly Elliptical Apogee = position furthest away from Earth Earth Perihelion = position closest to the sun Moon Perigee = position closest to Earth Sun Aphelion = position furthest away from the sun (Eccentricities greatly exaggerated!)

  14. Annular Solar Eclipses When Earth is near perihelion, and the moon is near apogee, we see an annular solar eclipse. The angular sizes of the moon and the sun vary, depending on their distance from Earth. Perigee Apogee Aphelion Perihelion

  15. Annular Solar Eclipses (2) Almost total, annular eclipse of May 30, 1984

  16. Conditions for Eclipses (1) The moon’s orbit is inclined against the ecliptic by ~ 50. A lunar eclipse can only occur if the moon passes a node near full moon. A solar eclipse can only occur if the moon passes a node near new moon.

  17. Conditions for Eclipses (2) Eclipses occur in a cyclic pattern. Saros cycle: 18 years, 11 days, 8 hours

  18. Asteroidial Occultation • An asteroid orbiting the sun sometimes get in front of a star as seen from the earth. • This type of Asteroidial occultation is used to measure the size of the asteroid • and to tell whether it has an any moons orbiting the asteroid. • Here the alignment is earth, asteroid, and star in that order. • http://scienceworld.wolfram.com/astronomy/Asteroid.html

  19. 29 October 2005 790 Pretoria

  20. Asteroidial Occulation Updates • http://www.asteroidoccultation.com/

  21. Lunar Occultation • Moon traveling in it orbit around the earth occults stars. • When it occurs near the top or bottom of the moon this is called a Grazing Lunar Occultation. As the star gazes behind the lunar edge profile the star appears to go out and then back on when it appears from a deep lunar valley. • Grazing lunar occultations are used to determine the lunar edge profile very accurately so that when solar eclipses happen and the last part of the photosphere appears in deep lunar valleys, forming Baily's Beads. The timing of these Baily's beads can be used to tell whether the sun is getting larger or smaller over time, by comparing Baily's beads timing from solar eclipse to solar eclipse. This is basic long term research that answers extremely important critical questions about the size of the sun and future changes in our climate on earth. Global warming or cooling and all of that sort of stuff. • Moon can get in from of a planet like Saturn (seen it).

  22. Lunar Occultation Links • http://www.lunar-occultations.com/iota/iotandx.htm

  23. February 20, 2002 Moon occults Saturn • http://antwrp.gsfc.nasa.gov/apod/ap020222.html Astronomy Picture of the Day February 22, 2002.

  24. Transist of Venus Across the Disk of the Sun June 8, 2004 • http://www.montgomerycollege.edu/Departments/planet/planet/VenusTransit.html • http://montgomerycollege.edu/Departments/planet/planet/Mercurytransit2006.html Transit of Mercury across the disk of the sun November 8, 2006. • http://sunearth.gsfc.nasa.gov/eclipse/transit/venus/Map2012-2.GIF Visibility of June 6, 2012 transit of Venus across the Sun.

More Related