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THE ORBIT OF VENUS. 8th EAAE Summer School De Glind (19-24 July 2004) Roland BONINSEGNA (Belgium). OBJECTIVES. Use simple observations to: confirm the heliocentric theory define Venus orbit compute Venus distance compute Venus revolution period. Galileo (1564-1642). SUN. SUN.
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THE ORBIT OF VENUS 8th EAAE Summer School De Glind (19-24 July 2004) Roland BONINSEGNA (Belgium) THE ORBIT OF VENUS
OBJECTIVES • Use simple observations to: • confirm the heliocentric theory • define Venus orbit • compute Venus distance • compute Venus revolution period THE ORBIT OF VENUS
Galileo (1564-1642) THE ORBIT OF VENUS
SUN THE ORBIT OF VENUS
SUN THE ORBIT OF VENUS
Using the transit times … 11h55 14h27 THE ORBIT OF VENUS
…to calculate the elongation angle. The Earth achieves one rotation (360 degrees) in 24 hours. What is the value of the rotation angle in 1 hour? 15° For 2004 January 31… Sun transit time: 11h55 Venus transit time: 14h27 2h32min = 2.53h 38° Elongation angle? THE ORBIT OF VENUS
Date View from Earth Transit times (U.T.) 2004 January 31 1 Sun: 11h55 Venus: 14h27 Elongation: E 2004 March 31 2 Sun: 11h45 Venus: 14h40 Elongation: E 38 E THE ORBIT OF VENUS
Date View from Earth Transit times (U.T.) 2004 June 8 3 Sun: 11h40 Venus: 11h40 Elongation: 0° 2004 August 17 4 Sun: 11h45 Venus: 08h45 Elongation: W THE ORBIT OF VENUS
Date View from Earth Transit times (U.T.) 2004 October 15 5 Sun: 11h27 Venus: 09h06 Elongation: W 2005 March 29 6 Sun: 11h46 Venus: 11h46 Elongation: 1° S THE ORBIT OF VENUS
Calculating the elongation angle - Results 2004 January 31 38° E 44° E 2004 March 31 0° 2004 June 8 45° W 2004 August 17 2004 October 15 35° W 2005 March 29 1° S THE ORBIT OF VENUS
Sun 38° Earth THE ORBIT OF VENUS
S 44° E THE ORBIT OF VENUS
Measure each Sun – Venus distance THE ORBIT OF VENUS
Measure each Earth – Venus distance THE ORBIT OF VENUS
Complete the table Distance Sun – Earth = mm THE ORBIT OF VENUS
Example of results Distance Sun – Earth = 100 mm THE ORBIT OF VENUS
6 3 Find the place of Venus for dates 3 and 6. Draw Venus orbit THE ORBIT OF VENUS
Distance Sun – Earth = 100 mm 100 mm = 1 Astronomical Unit = 15 x 107 km Mean official Sun – Venus distance: 0.723 A.U. THE ORBIT OF VENUS
Using your measures, calculate … OFFICIAL VALUES 1.126 0.695 0.289 0.706 1.137 1.724 THE ORBIT OF VENUS
6 • 31/01/04 • 31/03/04 • 8/06/04 • 17/08/04 • 15/10/04 • 29/03/05 584 d 3 Value of the Venus synodic period? THE ORBIT OF VENUS
584 d 584 d THE ORBIT OF VENUS
The Venus synodic revolution period 584 d 0 1 THE ORBIT OF VENUS
The Venus sidereal revolution period ? d 0 THE ORBIT OF VENUS
THE SIDEREAL REVOLUTION PERIOD OF VENUS Remember the value of Venus synodic revolution Period? VsP = 584 d Remember the value of Earth Sidereal revolution Period? ESP = 365.25 d THE ORBIT OF VENUS
THE SIDEREAL REVOLUTION PERIOD OF VENUS ESP = 365.25 d VsP = 584 d How to find the value of Venus Sidereal revolution Period? 1/VSP = 1/VsP + 1/ESP VSP = 224.7 d THE ORBIT OF VENUS
(0) 8/06/04 0 THE ORBIT OF VENUS
(0) 8/06/04 (1) 8/09/04 1 1 0 THE ORBIT OF VENUS
(0) 8/06/04 (1) 8/09/04 1 (2) 8/12/04 1 2 0 2 THE ORBIT OF VENUS
(0) 8/06/04 (1) 8/09/04 1 (2) 8/12/04 (3) 19/01/05 1 2 225 d 3 3 0 2 Value of one Venus sidereal revolution? THE ORBIT OF VENUS
(0) 8/06/04 (1) 8/09/04 1 (2) 8/12/04 (3) 19/01/05 (4) 19/04/05 1 2 4 3 3 0 2 4 THE ORBIT OF VENUS
(0) 8/06/04 (1) 8/09/04 1 (2) 8/12/04 (3) 19/01/05 5 (4) 19/04/05 1 2 (5) 19/07/05 4 3 3 5 0 2 4 THE ORBIT OF VENUS
(0) 8/06/04 (1) 8/09/04 1 6 (2) 8/12/04 (3) 19/01/05 5 (4) 19/04/05 1 2 (5) 19/07/05 4 (6) 31/08/05 6 3 3 0 5 2 An other Venus sidereal revolution! 4 THE ORBIT OF VENUS
(0) 8/06/04 (1) 8/09/04 1 6 (2) 8/12/04 (3) 19/01/05 5 (4) 19/04/05 7 7 1 2 (5) 19/07/05 4 (6) 31/08/05 (7) 1/12/05 6 3 3 0 5 2 4 THE ORBIT OF VENUS
(0) 8/06/04 (1) 8/09/04 1 6 (2) 8/12/04 (3) 19/01/05 5 (4) 19/04/05 7 7 1 2 (5) 19/07/05 4 (6) 31/08/05 (7) 1/12/05 6 3 8 (8) 13/01/05 3 0 8 5 2 Value of one Venus synodic revolution? 584 d 4 THE ORBIT OF VENUS
References • Gray B.J., 2002, Guide 8 software:http://www.projectpluto.com • Laurel C. et al., Celestia software • http://www.shatters.net/celestia • The Torbay Astronomical Society: • http://www.halien.com/TAS/ • View of the solar system (in different languages):http://www. solarviews.com/ss.html • Winther Mogens, Seeing is believing: • http://www. Amtsgym-sdbg.dk/as/venus/ven-dist.htm THE ORBIT OF VENUS