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Astrolabes A model of the universe you can hold in your hand. By Dr. Harold Williams

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Presentation on theme: "Astrolabes A model of the universe you can hold in your hand. By Dr. Harold Williams"— Presentation transcript:

1 Astrolabes A model of the universe you can hold in your hand. By Dr. Harold Williams

2 Internet Astrolabe resources Janus, Jim Morrison, best general source of astrolabe information on the net. The electric astrolabe a free download only works on Wintel machines. The best laminated in plastic plainspheric astrolabe. Janus, Jim Morrison, best general source of astrolabe information on the net. The electric astrolabe a free download only works on Wintel machines. The best laminated in plastic plainspheric astrolabe. oor2/gallery4/indastro/index.html Keith Powell's Java astrolabe. oor2/gallery4/indastro/index.html Keith Powell's Java astrolabe. oor2/gallery4/indastro/index.html oor2/gallery4/indastro/index.html

3 Astrolabe by Jean Fusoris Photo courtesy Adler Planetarium and Astronomy Museum Photo courtesy Adler Planetarium and Astronomy Museum It is 16.3 cm in diameter (6.4 inches) with an overall height of 20.6 cm (8.1 inches). The mater thickness is 0.8 cm (.31 inches). Probably made around It is 16.3 cm in diameter (6.4 inches) with an overall height of 20.6 cm (8.1 inches). The mater thickness is 0.8 cm (.31 inches). Probably made around Fusoris was one of the first philosopher- churchmen to set up a commercial workshop to produce instruments. He was successful and at least 13 of his astrolabes survive. Fusoris was one of the first philosopher- churchmen to set up a commercial workshop to produce instruments. He was successful and at least 13 of his astrolabes survive. Jean Fusoris born Giraumont in the Ardennes region of France 1365 to1436. Jean Fusoris born Giraumont in the Ardennes region of France 1365 to1436.

4 Part of the Astrolabe Rete, net in Latin, the star map, off axis circle the ecliptic (the zodiacal signs) Rete, net in Latin, the star map, off axis circle the ecliptic (the zodiacal signs) Plates ( climate or tympanum ), latitude specific, horizon coordinate system, altitude and azimuth Plates ( climate or tympanum ), latitude specific, horizon coordinate system, altitude and azimuth

5 Recently made Islamic Astrolabe Dr. Hasan Bilani, University of Aleppo, Syria November 2000 Dr. Hasan Bilani, University of Aleppo, Syria November 2000 It is not a reproduction of a specific instrument but is in the style of a typical, high quality Islamic astrolabe. It is not a reproduction of a specific instrument but is in the style of a typical, high quality Islamic astrolabe. It was designed using AutoCAD and was engraved by chemical milling. It was designed using AutoCAD and was engraved by chemical milling. It required about two months to manufacture. It is made of brass and is about eight inches in diameter and 5.5 mm thick and weighs 900 gm. There are 23 stars precessed to the current epoch. There are six plates provided but only two can but only two can be held in the mater at a time. The quote from the Koran on the throne (kursi) is "…and by the stars (men) guide themselves". It required about two months to manufacture. It is made of brass and is about eight inches in diameter and 5.5 mm thick and weighs 900 gm. There are 23 stars precessed to the current epoch. There are six plates provided but only two can but only two can be held in the mater at a time. The quote from the Koran on the throne (kursi) is "…and by the stars (men) guide themselves".

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7 Recently made Western Astrolabe Dr. John Jarvis, Eden Prairie, Minnesota, USA Dr. John Jarvis, Eden Prairie, Minnesota, USA John is a chemical milling professional and he applied his considerable knowledge of the process to making astrolabes with spectacular results. The style and quality of his astrolabes are as good as the best. John is a chemical milling professional and he applied his considerable knowledge of the process to making astrolabes with spectacular results. The style and quality of his astrolabes are as good as the best. Dr. Jarvis has been interested in astrolabes since the mid-70's after being introduced to them in a graduate astronomy course. He built his first astrolabe as a project for this course. His interest was rekindled in the mid-90s after purchasing a Personal Astrolabe from Janus. Dr. Jarvis has been interested in astrolabes since the mid-70's after being introduced to them in a graduate astronomy course. He built his first astrolabe as a project for this course. His interest was rekindled in the mid-90s after purchasing a Personal Astrolabe from Janus.

8 Rete

9 Janus astrolabe rete

10 Stereographic Projection of Rete For a rete to represent the Northern hemisphere For a rete to represent the Northern hemisphere

11 North pole, equator, and tropics projection

12 Ecliptic projection

13 Rete for 2800BCE

14 Rete for 500BCE

15 Rete for 140

16 Rete for 2000

17 Rete for 13400

18 Plate (climate or tympanium) Altitudes or almucanters Altitudes or almucanters Twilight Arcs, -6º Civil, - 12º Nautical, -18º Astronomical Twilight Arcs, -6º Civil, - 12º Nautical, -18º Astronomical Azimuths Azimuths North 0º & 360º North 0º & 360º East 90º East 90º South 180º South 180º West 270º West 270º

19 Altitude Projections

20 Lines of equal Azimuth Projection

21 Hour angle Projections

22 Complete Climate Projection

23 Climate for 25 degrees

24 Climate for 30 degrees

25 Climate for 35 degrees

26 Climate for 40 degrees

27 Climate for 45 degrees

28 Climate for 50 degrees

29 Climate for 55 degrees

30 Climate for 60 degrees

31 Plate for 0 and 90 degrees

32 Plate for ecliptic transformation

33 Plate for all horizons in 5 degree increments

34 Back of astrolabe Highly variable Highly variable But most had calendar and zodiac But most had calendar and zodiac & angle measuring protractor & angle measuring protractor Notice perihelion and aphelion and center of calendar & zodiac Notice perihelion and aphelion and center of calendar & zodiac

35 First Astrolabe I ever made

36 Second astrolabe I had a draftswomen do

37 Fred Whitle, a fellow graduate student’s astrolabe

38 The Electric Astrolabe a Wintel computer program

39 Janus astrolabe the college edition Set for July 25 at 10PM at Takoma Park, Latitude 38°58’.

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42 ET, equation of time, set for July 25, ET=-5.5 minutes or -5 minutes and- 30 seconds.

43 Grumman Linear Astrolabe


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