Howard SunCompass Spider

Using this azimuth spider for the Howard Sun Compass only one disk will be sufficient for the whole year.
Select "Options" and "Shadow on/off" before printing the disk (by a screen capture tool).
The disk diameter is 134 mm.

standard time

Check your time zone offset and select the local standard time.


Enter latitude in decimal degrees,
northern positive, southern negative.
Enter longitude in decimal degrees,
eastern positive, western negative,
Then press
the button Apply Input.

You may use the keys "y", "m", "d", "h", "n" to increase the year, month, date, hour, minute, or Shift key and "y", "m", "d", "h", "n" to decrease the year, month, date, hour, minute !

Click into the spider web to get the date and the azimuth.
apparent solar
                  timestandard time
Check the box to choose apparent (solar) time, uncheck for standard time.
apparent time
                  standard time
Select from the "Options" menu.
"on/off" items are working in toggle mode.
                  altitude equation of time rise set
The times of transit, sunrise, and sunset are standard time.


My Sundial Applets

Applets: Ancient Sundials and Quadrants

Web Links

The Sundial Primer: Spider Sundials

Horizontal Spider Sundial

Sonnenuhren-Spinne (Wikipedia)

Spinnensonnenuhr / Cadran solaire du type araignée (Yves Opizzo)

The Sundial Garden (Deutsches Museum Munic)

Double Foster-Lambert Sundial

Self-aligning sundial

Articles of  H.J. Hollander

Last Modified: 2016, Mar 11

© 2009-2016 Juergen Giesen