Eclipses, Occultations and Transits

An eclipse is the result of the total or partial masking of a celestial body by another along an observer's line of sight. Solar eclipses result from the Moon blocking the Sun relative to the Earth; thus Earth, Moon and Sun all lie on a line. Lunar eclipses work the same way in a different order: Moon, Earth and Sun all on a line. In this case the Earth's shadow hides the Moon from view. An occultation occurs when a celestial object is eclipsed by the Moon or another solar system body. A transit is either the act of one celestial body passing in front of another or the time at which a celestial object is highest in the sky. The time at which a celestial object crosses the meridian is called the transit time.

Radio Programs

Moon and Aldebaran Years of playing “peek-a-boo” Tuesday, January 19, 2016
Blood Harvest Super Moon Lining up names for the full Moon Sunday, September 27, 2015
Lunar Eclipse Lining up a skywatching treat Saturday, September 26, 2015
Moon and Aldebaran A stellar disappearing act Friday, September 4, 2015
Moon and Spica Creeping up on a bright star Friday, May 1, 2015
Lunar Eclipse Lining up a total lunar eclipse Friday, April 3, 2015
Eclipses Through the Ages A legacy from 1492 Thursday, April 2, 2015
Solar Eclipse Extra darkness for the Arctic Thursday, March 19, 2015
Occultations Illumination from darkness Friday, January 23, 2015
Moon and Uranus The Moon takes aim at a faint giant Monday, December 1, 2014
Epsilon Aurigae Playing Frisbee with a bright star Sunday, November 23, 2014
Solar Eclipse Darkening the afternoon sky Wednesday, October 22, 2014
Lunar Eclipse A repeat performance for the Moon Tuesday, October 7, 2014
Dabih Covering up a passel of stars Friday, September 5, 2014
More Lunar Eclipse Big entertainment in the night sky Monday, April 14, 2014
Lunar Eclipse Changing the course of history Sunday, April 13, 2014
Moon and Spica Lining up a lunar encounter Wednesday, January 22, 2014
Solar Eclipse A rare solar eclipse Saturday, November 2, 2013
Hunter’s Moon Hunting up a faint eclipse Friday, October 18, 2013
Moon and Spica Lining up a celestial encounter Monday, July 15, 2013
A New Cycle Beginning a new lunar cycle Friday, May 24, 2013
Annular Eclipse A ring of fire above the Pacific Ocean Thursday, May 9, 2013
Moon and Spica Illumination from a disappearing act Thursday, February 28, 2013
Epsilon Geminorum A star by the numbers Thursday, January 17, 2013
Feeble Eclipse Earth casts a feeble shadow on the Moon Tuesday, November 27, 2012
Solar Eclipse Diving into a natural wonder Monday, November 12, 2012
Eclipse Watcher Risking life and limb for a solar eclipse Sunday, August 19, 2012
Cloudy Skies A cruel twist of nature Saturday, August 18, 2012
Solar Spotters Getting a better bead on the Sun Wednesday, June 6, 2012
Venus Transit II A last-in-a-lifetime event Tuesday, June 5, 2012
Venus Transit Measuring out a solar-system ruler Monday, June 4, 2012
Partial Lunar Eclipse Taking a “bite” out of the Moon Sunday, June 3, 2012
Celestial Geometry A hubbub over celestial geometry Saturday, June 2, 2012
Transit and Eclipse Lining up with Earth and the Sun Friday, June 1, 2012
Annular Eclipse II Cycling through centuries of eclipses Sunday, May 20, 2012
Annular Eclipse A ring of fire in the afternoon sky Saturday, May 19, 2012
Happy Coincidence A beautiful scientific coincidence Friday, May 18, 2012
Clockwork Eclipses Ticking off the hours until a solar eclipse Thursday, May 17, 2012
Balloon Ride Taking a balloon ride for science Saturday, April 7, 2012
Rings of Uranus A dark discovery for a giant planet Thursday, March 8, 2012
Lunar Eclipse Lining up a lunar eclipse Friday, December 9, 2011
Solar Eclipse Darkening sun-lit southern skies Friday, November 25, 2011
New Moon Blazing through the lunar night Friday, July 1, 2011
Moon and Antares The sweetness of a full Moon Tuesday, June 14, 2011
Transit of 1761, Part II Dodging cannonfire in the name of science Tuesday, June 7, 2011
Transit of Venus One year away from a rare event Sunday, June 5, 2011
Partial Solar Eclipse A feeble northern Sun Tuesday, May 31, 2011
Moon and Spica Paying a call on an old friend Saturday, May 14, 2011
Epsilon Aurigae A long-lasting stellar eclipse Monday, March 28, 2011

Featured Images

Total lunar eclipse, October 2014
Lunar Eclipse Saturday, September 26, 2015
Space-based view of solar eclipse of March 20, 2015
Disappearing Sun Friday, March 20, 2015
Artist's concept of Epsilon Aurigae
Playing Frisbee Sunday, November 23, 2014
The Moon occults Dabih, a star in Capricornus
Celestial Cover-Up Friday, September 5, 2014
Peek-a-Boo Friday, January 31, 2014
Solar eclipse of August 19, 1887, from near Berlin
Fire in the Sky Saturday, August 18, 2012
June 5, 2012, Venus transit from International Space Station
Seeing Spots Saturday, June 9, 2012
Diagram of Venus transit of June 5, 2012
Sun Spot Monday, June 4, 2012
Partial lunar eclipse of June 4, 2012
Lunar Nibble Saturday, June 2, 2012
Illustration of annular eclipse of May 20, 2012
In the Zone Friday, May 18, 2012
Venus's path across the Sun during the transit of 1761
Bright Passage Monday, June 6, 2011
Total Lunar Eclipse of December 21, 2010
Disappearing Moon Monday, December 20, 2010


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