J. Giesen's
Sundial Applets

Helios / Sol

Open Register.htm

1. Analemma Sundial

An analemma is the figure-of-eight shape that results if the Sun's position in the sky is recorded at the same time of day throughout the year. The gnomon of a sundial draws a similar figure.

Print the diagram to make your own sundial !

2. Horizontal Sundial

3. Pie Sundial

Make your own sundial just by folding a sheet of paper.
Java applet drawing a cylinder sundial indicating clock time.

4. Cylinder Sundial

Java applet drawing a cylinder sundial indicating clock time.

5. Sundial Box

Java applet drawing an hour scale for a Compact Disk.
6. Spider Sundial
A horizontal sundial using a vertical gnomon. It depends on the azimuth angle of the Sun.
7. Spider:
Vertical and Polar Pointing Gnomon

A horizontal sundial using a vertical gnomon. It depends on the azimuth angle of the Sun.
8. North Finder
This horizontal sundial combines two different principles and is self-aligning to true north.
9. Bifilar Sundial
This sundial uses two non-intersecting threads parallel to the horizontal dial plane. The upper thread (distance a above the plane) is oriented North-South, the lower (distance b) is orthogonal to the first. The intersection of the two threads' shadows gives the time.
10. Cone Sundial
This sundial uses a horizontal gnomon. The hour lines and the date lines are drawn on to a cone.
11. Babylonian, Italian, Unequal Hours Sundial
The Babylonian system divides the day into 24 equally long hours beginning at sunrise and ending with the following sunrise.
Italian hours begin counting at sunset and ends 24 hours later with the following sunset.

12. Pingre Sundial
This unique sundial was invented and designed by the French astronomer Alexandre Guy Pingré (1711 - 1796).
It is similar to the cylinder sundial, but there are multiple gnomons in a horizontal plane, perpendicular to the cylinder.

13. Daylight Hours Sundial
The gnomon of this sundial is vertical. The shadow of it's top on the horizontal plane is used to read the sundial.
The declination lines are computed for full numbers of daylight hours which depend on the latitude of the observer and the declination of the Sun.

14. Sidereal Time Sundial
This horizontal sundial is showing the local sidereal time, which is defined as the hour angle of the vernal equinox.
15. Foster-Lambert Sundial
The gnomon produces a circular ring of equiangular hour points.
16. Azimuthal Orthographic Sundial

Azimuthal Sundial for both solar and standard time.

17. Gnomon
This type of sundial has a vertical
gnomon casting the shadow on a horizontal plane.

Sun:
Declination, Equation of Time, Transit Time

Tables, and diagrams.

Sun Data

The applets computes the times of sunrise and sunset, and more astronomical data, which are updated every second.

Sunrise & Sunset

The applet displays the times of sunrise and sunset.

Declination &
Equation of Time

The applet displays the current declination of the sun and the equation of time.

Current Declination
& Equation of Time

The applet displays the current declination of the sun and the equation of time.

Sunrise and Sunset

You may edit the applet parameters for your location and the number of lines.

Azimuth and Elevation

You may edit the applet parameters for your location and the number of lines.

SunClock

Twilight Clock

Spider Sundial