THE SUNDIAL (EQUATORIAL DIAL WATCH)
- Building sundials-
In the previous installment we meet the challenge of making a sundial diffraction using a Fresnel lens, in this issue will make a sundial equatorial dial.
of sundials, perhaps the most simple and easy to do is dial the equator due to the limited calculations necessary for development. Here we will take steps to manufacture roughly taking into account that always the designer's imagination is the limit in terms of forms is concerned.
The simplest of these watches are made from equatorial circle, dividing it into two parts equal and grading the bottom half of the disc from the center of it into 12 equal parts, each division corresponds to one hour (15 º) day. In the center of the disc and perpendicular to the surface of the place a straight wire, which is the gnomon. This sundial rudimentary so inclined with respect to the vertical the same number of degrees of latitude of where we are, for example, if we are at 30 degrees north, our sundial must be tilted with respect to the vertical 30 degrees south .
The following image shows the template of our little solar project, in which the foot or stand serves the dual function of holding the dial parallel to the sky and Ecuador gnomon. This foot is designed so that its top edge will act as the gnomon and parallel to the axis of the poles, ie the horizontal angle corresponds to your latitude.
templates we stuck on a thin cardboard to cut away the parts that make up the clock.
Cut out the pieces, the two squares are joined together to form a single rigid unit. In the bottom of the quarters, where he placed his foot, practiced a slot with the exact depth equal to the height of the foot at its midpoint, the same way, the foot was performed the court but with the thickness of the upper quadrant.
Finished parts are necessary to assemble the clock.
Quadrant front or north side.
Quadrant
rear or southern side.
Vista
quadrant.
Side view. Note
last image sundial tilt (with respect to the vertical, the tilt angle is equal to the latitude of the place, in this case 8 º North) and the top of the foot is perpendicular to the dial and centered with the origin of the lines indicating the hours. Recall that in this model, the upper edge of the foot is the gnomon, and must be parallel to the axis of the world.
Made the clock, we can place it in an open and oriented so that the foot is under the direction of the meridian of the place, ie parallel to the axis of the poles. Tell us when the shadow created by the upper edge of the foot (gnomon) which is aligned with a division time indicator.
Local Solar Time: 11:00 AM
Understanding how Solar clock such, we are able to make other models projecting the equatorial quadrant on another level such as the horizontal.
The watch and clock equatorial diffraction.
In the next release will try to make a vertical sundial dial, which has a degree of difficulty greater than the equator.
