The REAL OCCULT: Lunar & Solar Eclipses and Asteroid & Stellar Disappearances Sometimes Involving Luna

• The shadow of the earth gets in front of the full moon at night time, a Lunar Eclipse, 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).  Photographs taken from outside the planetarium during the lunar eclipse on 27 of  October 2004.
  
• The new moon gets in front of the sun in the day time, a Solar Eclipse, 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, 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, some of the finest pictures taken by a true artist of solar eclipses and music.   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.   For the partial solar eclipses, or any other time you want to look at the sun, except during totality, you need protection.  For solar protection, good filters are very important, see:  
• http://www.eclipse1999.com/
• http://www.handsonoptics.com 301-482-0000 or 301-482-2210 Hands on Optics in Damascus, MD 20872, they carry good filters and are local.  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.  July 11, 1991, travel was arranged by Eclipse Edge of MetaResearch,  a report on the eclipse expedition is here. This was my first total solar eclipse and my only edge solar eclipse so far.  On February 26, 1998 at Curacao, in the Netherlands Antilles. the National Capital Astronomers, NCA, arrange an eclipse trip while I was president of this organization.  I am now webmaster of NCA.  I viewed the eclipse from near the centerline.  It was spectacular, but if I have a choice, at the next total eclipse I will go to an edge eclipse again.  I loved the way the Baily's Beads danced on the edge for a moment.  Tom Van Flanderin eloquently explains it this way.  Total Solar eclipses are awesome physical and spiritual events.  Once you have seen one total solar eclipse you will want to see another.  There are a lot of false rumors and gross ignorance about total solar eclipses being dangerous.  
  
• Very Partial Eclipse of the Sun on April 8, 2005 with some pictures
  

• 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.
• The moon traveling in it orbit around the earth occults stars; this is called a Lunar Occultation, 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.
• There are also other types of rarer occultations like Saturn disappearing behind the moon (seen it).   The moon of Jupiter, Io, Europa, Ganymeade, and Callisto disappearing being Jupiter (seen it).  Transits of Mercury across the disk of the sun (seen it) next one November 8, 2006; and the much rarer transit of Venus across the disk of the sun.  The next transit of Venus across the sun is June 6, 2012; and, of course, many many others.

• Sky & Telescope Occultation Primer article
  
• IOTA, International Occultation Timing Association, Time critical information
• IOTA, International Occultation Timing Association, David Dunham, an NCA member, sight. David Dunham is the leader of the occultation pack, who has done more occultations than anyone else alive, and has motivated and lead more occultation expeditions than any one else.
• IOTA, International Occultation Timing Association
• IOTA asteroids, International Occultation Timing Association Asteroids

Montgomery College's Planetarium home page

Web page by Dr. Harold Alden Williams.
Last changed 4:10PM EST October 29, 2005.