Capricorn: Dec.22-Jan.29 The Sundial Primer
created by Carl Sabanski
Capricorn: Dec.22-Jan.29

The Sundial Primer Index

ZW2000 Features - Fer de Vries

ZW2000 has available to the user additional features that you will find very useful. Figure 1 shows the opening screen when the software is started. At the lower left are two buttons. One shows an analemma and will take you to a dialogue box called "graph eot / decl" and the other, a black and white square, will take you to a dialogue box called "graph time limit". These dialogue boxes are shown in the figure and are described in further detail below.

Figure 1: ZW2000 Features

Figure 1: ZW2000 Features

graph eot / decl

This feature will draw a graph of the Equation of Time. It allows for the selection of a year in the range of 1902 to 2202. Only every fourth year can be selected and this year is in between leap years. When the "OK" button is selected a message may appear warning that the year selected does not match the data in the input screen used to design a sundial. Select "OK" and the drawing shown in Figure 2 appears. The drawing contains both the graphs of the Equation of Time and the sun's declination.

Selecting the "Clipboard" button will copy the white area and everything inside, including the text, to the Clipboard. The image can be pasted into another document but no revisions can be made to it.

 Figure 2: ZW2000 Features - "graph eot / decl"

Figure 2: ZW2000 Features - "graph eot / decl"

This drawing is also automatically saved as a clipped file or "*.clt". This file can be accessed by selecting "Load File" and then "Clipped file *.CLT" from "List files of type:". Select the file "eot_decl" and the drawing shown in Figure 3 will appear. Note that there is no text in this drawing. However, additional options are available for handling the drawing. The most significant is being able to save it as a "DXF" file.

Figure 3: ZW2000 Features - "graph eot / decl" - Clipped File

Figure 3: ZW2000 Features - "graph eot / decl" - Clipped File

Selecting the "Mult" button displays the "Multiply" window shown at the lower right in Figure 3. This table lists the X / Y co-ordinates of all the lines in the drawing. These values can be multiplied by a factor by selecting the "Factor = 1" button and the table can be saved as a text "TXT" file.

graph time limit

This feature will draw a graph that indicates the time during which any arbitrarily oriented surface will be illuminated by the sun throughout the year. This information is useful for determining the range of the hour lines to be included on a sundial. The "latitude", "dial inclination" and "dial declination" must be entered. Figure 4 shows the drawing for a dial plane with entered values of 51.5, 90 and 15. The sundial is located at a latitude of 51.5 N, is vertical (90) and declines to the west by 15. The sundial will be illuminated during the times shown between the red lines that indicate sunrise and sunset.

Figure 4: ZW2000 Features - "graph time limit"

Figure 4: ZW2000 Features - "graph time limit"

The blue lines indicate the times of sunrise and sunset of the equivalent horizontal plane. What this means is a plane that is not horizontal at a given location on the earth can be moved to another location on earth where it is horizontal. A simple example is a vertical direct south plane at any latitude is a horizontal plane at the co-latitude. There is more information about sundial equivalency on the "Incl / Recl / Procl Sundials" page.

All the comments provided above regarding the handling of the "graph eot / decl" drawing apply here as well.  The name of the clipped file is "time_lim.clt".