Moon January – Wolf moonWolf moon February – Snow moonSnow moon March – Storm moonStorm moon April – Pink moonPink moon May – Flower moonFlower moon June – Strawberry moonStrawberry moon July – Buck moonBuck moon August – Sturgeon moonSturgeon moon September – Harvest moon October – Hunter's moon November – Beaver moonBeaver moon December – Cold moonCold moon

Models of Universe Ptolemy – Earth Centered (geocentric) – Epicycles to explain Retrograde Motion – Very accurate with the data available Copernicus – Sun Centered (heliocentric) – Movement of earth and planet explained Retrograde Motion – New data – Not a lot more accurate Both proposed as “tools” not reality

4 TYCHO BRAHE ( )

Brahe’s Life EclipseEclipse which occurred on 21 August 1560, particularly the fact that it had been predicted, so impressed him that he began to make his own studies of astronomy, 1576: Tycho Brahe received the island Hveen from King Fredrik II of Denmark. There he built castle Uranienborg. Tycho Brahe studied the stars at Uranienborg and Stjärneborg. 1597: Tycho Brahe looses the royal support and leaves the island. Tycho goes to Wandsbech (near Hamburg) and then to Prague.

7 Brahe’s Life Emperor Rudolf II gave him the castle Benatky 30 km from Prague, but he later moved to a house in Prague better suited for observations. 1600: Brahe employed Johannes Kepler. Kepler’s task was to put Brahe’s model on a firm mathematical foundation. Brahe urged Kepler to “declare war on Mars.” 1601: Tycho Brahe died. Kepler writes down his last words: "Ne frustra vixisse videar" (May I not seemed to have lived in vain.)

Fun Guy While a student, Tycho lost part of his nose in a duel [7] with Manderup Parsbjerg, a fellow Danish nobleman. [8] This occurred in the Christmas season of 1566, after a fair amount of drinking, while Tycho, just turned 20 years old, was studying at the University of Rostock in Rostock, Germany. [8]] For the rest of his life, he was said to have worn a realistic replacement made of silver and gold [7], using a paste to keep it attached. [noseduel [7] [8] Christmas seasonUniversity of Rostock [8]]silvergold [7] [

Tycho's Toys Tycho was said to own one percent of the entire wealth of Denmark at one point in the 1580s and he often held large social gatherings in his castle. He kept a dwarf named Jepp (whom Tycho believed to be clairvoyant) as a court jester who sat under the table during dinner.clairvoyantjester Tycho also had a tame moose (called an Elk in Europe). Apparently during dinner the moose had drunk a lot of beer, fallen down the stairs, and died.mooseElk in Europe

Hven

The building was dedicated to Urania, the Muse of Astronomy It was the first custom-built observatory, and the last to be built without a telescope as its primary instrument. Urania telescope Uranienborg

Drawing for Main Building

First Research Center Tycho established the Uranienborg as a research center where almost 100 students and artisans worked from 1576 to 1597

14

15 Brahe’s Instruments

16 Brahe’s Instruments

17 Brahe’s Instruments

Measuring Angles between

Mural Sextant

20 Brahe’s Observations  Brahe was primarily an observational astronomer who devoted himself to a systematic study of the errors in the astronomical instruments (all naked-eye -- not telescopic) of his day.  He continually redesigned and rebuilt his instruments until he could improve them no more.  He claimed an accuracy of +/- 1' of arc (1/21600th of a circle) for his fixed star positions and +/- 4' for his planetary positions.

21 Astronomical Achievemnents  Tycho Brahe made a remarkable star catalogue of over 1000 stars, far more than any astronomer before him.  He proved that comets are not objects in the atmosphere.  He showed irregularities in the moons orbit.  His wall quadrant and other instrument became widely copied and lead to improved stellar instruments.

22 Brahe’s Observations  In particular, he made long sequences of observations of the orbits of planets extending over a period of about 30 years.  He also observed what he thought (incorrectly) was a new star, called nova for new, in 1572 and, by accurate measurements of a comet's orbit in 1577, he showed it was much further away than the moon.

23 Brahe’s Nova 1572: He found a new star, Stella Nova, in the formation Cassiopei

Remnant of Tycho’s Nova

25 Brahe’s Comet (1577)

Parallax 26 January June Apparent location of star

No Parallax

Tycho’s Conclusions Nova and comet showed no parallax, therefore very far from earth. Ie. Celestial Objects Furthermore Either the earth did not move Or The stars were extremely distant

Tycho’s System

Tycho’s Death as told by Kepler “Holding his urine longer than was his habit, Tycho remained seated. Although he drank a little overgenerously and experienced pressure on his bladder, he felt less concern for the state of his health than for etiquette. By the time he returned home he could not urinate any more.”

Death Theories Recent investigations have suggested that Tycho did not die from urinary problems but instead from mercury poisoning:mercury Tycho may have poisoned himself by imbibing some medicine containing unintentional mercuric chloride impurities, or may have been poisoned.mercuric chloride One theory proposed in a 2005 book by Joshua Gilder and Anne-Lee Gilder, suggests that there is circumstantial evidence that Kepler murdered Tycho; Kepler had the means, motive, and opportunity, and stole Tycho's data on his death.

32 Astronomical Achievemnents Kepler used Tycho Brahe's observations when he constructed his famous laws of planetary movement.

Next Time Kepler

On 11 November 1572, Tycho observed (from Herrevad Abbey) a very bright star, now named SN 1572, which had unexpectedly appeared in the constellation Cassiopeia. Because it had been maintained since antiquity that the world beyond the Moon's orbit was eternally unchangeable (celestial immutability was a fundamental axiom of the Aristotelian world-view), other observers held that the phenomenon was something in the terrestrial sphere below the Moon. However, in the first instance Tycho observed that the object showed no daily parallax against the background of the fixed stars. This implied it was at least farther away than the Moon and those planets that do show such parallax. Moreover he also found the object did not even change its position relative to the fixed stars over several months as all planets did in their periodic orbital motions, even the outer planets for which no daily parallax was detectable. This suggested it was not even a planet, but a fixed star in the stellar sphere beyond all the planets. In 1573 he published a small book, De nova stella thereby coining the term nova for a "new" star (we now classify this star as a supernova and we know that it is 7500 light-years from Earth). This discovery was decisive for his choice of astronomy as a profession. Tycho was strongly critical of those who dismissed the implications of the astronomical appearance, writing in the preface to De nova stella: "O crassa ingenia. O caecos coeli spectatores" ("Oh thick wits. Oh blind watchers of the sky").1572Herrevad AbbeySN 1572 CassiopeiaantiquityAristotelian parallax1573novasupernovalight-yearsDe nova stella