from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A graduated scale in the shape of a figure eight, indicating the sun's declination and the equation of time for every day of the year and usually found on sundials and globes.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An egg-shaped or figure-eight curve that results when the Sun's position in the sky is plotted out over the year at the same hour of mean solar time every day.
from the GNU version of the Collaborative International Dictionary of English
- n. An orthographic projection of the sphere on the plane of the meridian, the eye being supposed at an infinite distance, and in the east or west point of the horizon.
- n. An instrument of wood or brass, on which this projection of the sphere is made, having a movable horizon or cursor; -- formerly much used in solving some common astronomical problems.
- n. A scale of the sun's declination for each day of the year, drawn across the torrid zone on an artificial terrestrial globe.
from The Century Dictionary and Cyclopedia
- n. A form of sun-dial, now disused.
- n. In geometry, an orthographic projection of the sphere on the plane of the meridian, the eye being supposed to be at an infinite distance, and in the east or west point of the horizon.
- n. Hence An instrument of wood or brass on which a projection of this nature is drawn, formerly used in solving astronomical problems.
- n. A tabu-lated scale, usually drawn in the form of the figure 8, depicted across the torrid zone on a terrestrial globe, to show the sun's declination and the equation of time on any day of the year.
The analemma is a basis for calculation deduced from the course of the sun, and found by observation of the shadow as it increases until the winter solstice.
For more information about the Analemma Society, visit www. analemma.org.
Let the hours be marked off transversely on the column from the analemma, and let the lines of the months also be marked upon the column.
For it is from this revolution of the firmament, from the course of the sun through the signs in the opposite direction, and from the shadows cast by equinoctial gnomons, that we find the figure of the analemma.
This is because the length of the shadow at the equinox is used in constructing the figure of the analemma, in accordance with which the hours are marked to conform to the situation and the shadow of the gnomon.
Whoever wishes to find their baseplates, can easily do so from the books of these writers, provided only he understands the figure of the analemma.
This having been drawn and completed, the scheme of hours is next to be drawn on the baseplates from the analemma, according to the winter lines, or those of summer, or the equinoxes, or the months, and thus many different kinds of dials may be laid down and drawn by this ingenious method.
The hours, indicated by bronze rods in accordance with the figure of the analemma, radiate from a centre on the face.
One neat, modern trick we've been able to photograph is an analemma, or a picture of the Sun at the same exact time on different days over the course of a year.
What two features of the earth and its revolution are responsible for the analemma shape?