Quadrant Dial

This quadrant is a portable altitude sundial for a single latitude.
The instrument is equipped with a simple Sun sight on one edge. A weighted thread with a sliding bead is hanging from the apex.

See instructions for interactive use below

Overview: Dials and Quadrants

Visit my Applet Collection

Details for interactive use:


Enter the latitude (decimal degrees) into the text field and hit"Apply input".
The latitude is indicated in the lower right.

The interactive regions (light gray scales) are changing the cursor to cross hair.
Click into the light gray date scale to set the bead.
pper scale: Dec 21 - Jun 21, or lower: Jun 21 - Dec 21.
Click into the degree scale (light gray) on the limb to direct the sight to the Sun.

Use the "Today" button to set the bead to the current date.

Morrison, James E.: The Astrolabe, Janus. Softcover edition, 2007,
Rehobot Beach, DE USA,
ISBN-10: 0939320304, ISBN-13: 978-0939320301.

Hügin, Johannes: Das Astrolabium und die Uhr, Ulm, 1978,
ISBN 3-921348-23-4.

Rohr, Ren
é R. J.: Die Sonnenuhr. Geschichte, Theorie, Funktion.
Callwey, München 1982.

Meyer, Jörg: Die Sonnenuhr und ihre Theorie.
Harry Deutsch, Frankfurt 2008.

Zenkert, Arnold: Faszination Sonnenuhe (mit CD-ROM),
Harry Deutsch, Frankfurt 2000.
Web Links

Quadrant Sundial (PostScript file by Valentin Hristov)

The Astrolabe (James E. Morrison)

Gunter's Quadrant (J. E. Morrison, PDF)

Edmund Gunter biography (MacTutor History of Mathematics archive)

Gunter's quadrant (Navigation Museum)

Gunter quadrant (The Whipple Museum)

A Gunter quadrant and practical knowledge (The Whipple Museum)

Gunter quadrant (National Maritime Museum)

The Electric Astrolabe (J. E. Morrison)
executable file and documentation

Astrolabium (Deutsches Museum)

Der Gunter-Quadrant (Gunter W.)

Das Astrolab (Informatik Uni Erlangen)

Keith's Asterolabe (Java applet)

Literature on astrolabes (M. Brunold)

© 2009-2013 J. Giesen

Last modified: 2013, Jul 31