Lecture 7: Brightnesses Of Stars Magnitude System. Traditional system dating to classical times (Hipparchusof rhodes, c. 300BC). Rank stars into 1st, 2nd, 3rd, etc. magnitude. http://www-astronomy.mps.ohio-state.edu/~pogge/Ast162/Unit1/bright.html
Extractions: Stellar Brightness Key Ideas: Apparent Brightness of a star depends upon Inverse Square Law of Brightness How "Bright" is an Object? We must define the "Brightness" of an object quantitatively. Two ways to quantify brightness: Luminosity Luminosity is the total energy output from an object. The Luminosity of a star is a measurement of its total energy production. Apparent Brightness Measure of how bright an object appears to be as seen by a distant observer. What we measure here on earth (an "observable"). Measured in Flux Units Depends on the Distance to the object.
Prior Astronomer Next Astronomer Back To List He observed between 146 and 127BC from the city of rhodes and his cataloguementions the nebulae M44 and the Perseus double cluster. http://www.astrosurf.com/cielextreme/page98E.html
Extractions: This greek philosopher compiled the first catalogue of stars (at least the first we keep the trace of) containing about a thousand. He observed between 146 and 127BC from the city of Rhodes and his catalogue mentions the "nebulae" M44 and the Perseus double cluster. He introduced the notion of magnitude to estimate stars' brightness. The catalogue of PTOLEMY is largely inspired by this catalogue.
Astronomy Links - Early Astronomy Eratosthenes of Cyrene St Andrew's University page. hipparchus ofRhodes St Andrew's University page; Cornell University page. http://www.olemiss.edu/courses/astr103/Topics/Ancient-L.html
Extractions: (See also Renaissance astronomy and modern History of astronomy History of Astronomy Archaeoastronomy Antiquity and Topics Medieval Astronomy Astronomy in Different Cultures Arabs: A. Zahoor's site on Muslim scientists. Babylonians: St Andrew's University pages on Babylonian mathematics and numerals Greeks: Greek cosmology page Mayas: Maya astronomy page ; The Dresden Codex text and image pages.
The Famous Mathematician Internet Project The Famous Mathematician Internet Project. Mathematics is a living,breathing, vibrant discipline connected to many walks of life. . http://198.190.226.3/users/ham/famousmath.html
Mabon - Overview By Christina This is known as the precession of the equinoxes (first noted by Hipparchusaround 120 BC and explained in 1687 by Sir Isaac Newton). http://www.witchvox.com/holidays/mabon/mabon_details.html
Extractions: also known as: Mabon, Alban Elfed, Winter Finding, Mikeli, Harvest Moon Festival, Mea'n Fo'mhair The Second or Continuing Harvest. Now, as at Ostara, the days and nights are equal once again. gardens are in full bloom and heavy with nature's bounty. There is a slight nip in the air already and preparations begin to prepare for the long cold months which are to come.
