Analemmatic sundial

In this case the size of the hour marker ellipse is constrained by human height and the latitude of the sundial location, since the human gnomon shadow must fall on the hour marker ellipse to accurately indicate the time of day.

Rohr states "The gnomon is displaced on the short axis of the ellipse and not on the meridian, whose presence here in the shape of an 8 is a mistake.

The noon hour line points true North, whereas the hour lines for 6am and 6pm point due West and East, respectively; the ratio of the short to long axes equals the sine sin(Φ) of the local geographical latitude, denoted Φ.

[7] However, the vertical gnomon does not always stand at the centre of the hour lines; rather, to show the correct time, the gnomon must be moved daily northwards from the centre by the distance where W is half the width of the ellipse and δ is the Sun's declination at that time of year.

[8] The declination measures how far the sun is above the celestial equator; at the equinoxes, δ=0 whereas it equals roughly ±23.5° at the summer and winter solstices.

Analemmatic sundial on a meridian line in the garden of the Herkenrode Abbey in Hasselt ( Flanders in Belgium )
Analemmatic sundial in which the Barbate lighthouse forms the gnomon of the dial
Horizontal analemmatic sundial for 44°29' N drawn with Shadows Expert software. It shows local time
The terminology of sundial classification can be misleading. Although it features an analemma, this analemmic heliochronometer, end of 19th century, is not an analemmatic sundial - refer to the definition given in the text. Exhibit of the National Polytechnic Museum , Sofia