De Zonnewijzerkring

Zw2000 is intended to give you an accurate and exportable drawing of all the lines and curves you will need to make the sundial you wish to construct. It will not draw a complete sundial with all the numerals, mottos or whatever you might eventually wish to include.

Once you have produced the basic drawing you can use Zw2000 to modify it and choose which parts you want for your finished sundial. Your modified drawing can then be saved in a number of formats compatible with many other programs. These programs can be used to add the numerals, furniture, and any other personal enhancements you wish.

I am thankful to several members of Sundial Societies from all over the world who were very helpful with suggestions and corrections etc. during the development of this program.

If you want to know more about sundials and you aren't a member of one of the Sundial Societies now is the time for you to join.

Manual

We will learn the program by drawing a sundial step by step.

Figure 1 shows the opening screen which is an important sundial in Utrecht, Netherlands. This is a splash screen that will not show up while the program is in use. From this screen you may also load existing dial projects, but at this point, there aren't any.

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Select [New sundial] and a new screen appears as shown in figure 2. On this screen you will enter all the data for the desired dial.

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Although not necessary, it is recommended that you start by choosing a filename for the sundial by selecting [filename without extension]. A standard Windows "Save As" dialog window will appear. Enter the name AAAA. Be aware that at this point you are only naming a new project. The file will not actually be saved until you calculate and draw the dial.

In the blue area below the file name select the type of sundial you wish. Let's start with an ordinary flat (planar) sundial.

Some dials require the program to calculate the equation of time. These values can be based on any year from 1900 through 2200. Unless you are experimenting, it is recommended that you choose a year some time in the future which is in the middle of a leap year period. 2014 or 2022 are good selections.

The next step is to enter the constants of your dial.

Entering and accepting data in the yellow boxes recalculates other constants of the dial in the blue area at the lower left of the screen. This area only appears for the usual planar type of dial that we are constructing now. All dials can be oriented to any direction by entering values for dial inclination and dial declination

The data shown in figure 2 are for a vertical south facing sundial in Eindhoven, Netherlands. The city where I live.

For horizontal dials the inclination of the plane is 0. The declination for horizontal dials is also calculated as 0, although this is not indicated on the screen.

The right side of the screen is where you enter the data for the desired lines and curves.

Use the checkboxes to select the lines you want. For most of the line types the default "begin, end, step" values will do, but they may also be edited.

For Islamic prayer lines there is no choice, 3 lines are always calculated.

The following is the procedure for including date lines (day month) and declination lines. There are 2 predefined choices for date lines and declination lines as shown on the screen, but you may also opt for "none".

Clicking the red box will bring up an input screen for entering custom dates. Note the syntax in the right window is day/month. If this box is green it indicates that you have added custom dates. If it is red there are no custom date lines.

Figure 3 shows that a custom line has been added for May 1st.

The custom lines may be chosen in addition to the predefined lines, however in this example no predefined date lines have been chosen.

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Figure 4 shows the extra declination lines option screen with an empty list. With this configuration you will have a red box on the data input screen.

Although declination lines on a sundial have to be in the range from -23.44 to 23.44 degrees, Zw2000 allows declination lines in the range from -90 to 90. With this feature you can visualize how declination lines would look if the sun's declination fell outside its normal limits. The additional range gives an opportunity for theoretical exploration.

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The following table shows a summary of the options selected for our dial "AAAA". These are the same as those shown in figures 2 through 4.

Since we have now completed all our options select [calculate and draw] and the program will return to screen 1, with the drawing of the new sundial AAAA. The result is shown in figure 5.

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When you select [calculate and draw] the dial will be saved to disk as AAAA with the extension .rlt.

At the bottom of the screen you will be see the filename, gnomonlength and scale. The length of the gnomon is also drawn in red at the top of the dial.

You can pan the drawing across the screen by holding down the left button of your mouse, and moving the cursor to a new position. When the mouse button is released the drawing will be moved to the new point.

Selecting [Shift] will bring up a dialog where you may enter x,y coordinates for the new position of the drawing.

By selecting [Scale] the drawing can be scaled. The format is 1 : scale.

Selecting [Settings] will bring up the screen shown in figure 6.

Here you will find the same A through Z codes as on the data input screen, but with prefix L_. These are the names of the Layers in which all the line types are placed. Only the layers in which lines have been calculated will be colored.

Clicking the description on a particular line will change its color from green to red and vise-versa. If the color is green, the lines will be drawn, if red the lines will not be drawn, although the data for the lines will still be in the saved file.

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Clicking on the small black boxes will open a dialog in which the color of a layer can be changed. The small box will change to the selected color.

Checking the option Clip Window Visible will allow you to add a frame with dimensions of your choice entered in the Height and Width boxes. This frame should be a representation of your real dial's frame. Try to visualize that the size of the drawing corresponds to the one on your screen and that the dimensions are in millimeters.

The scaled and shifted drawing with the clip marks included can be seen in figure 7.

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On the left side of the screen, select [Clip]. Choose a filename, perhaps the same name with an added number, and your sundial will be saved with all parts of the lines outside the frame cut off. This can be seen in figure 8.

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This clipped dial now has a filename with the extension .clt, while the original file still has the extension rlt. This is how you can choose the portion of a calculated dial that fits best on your plane.

Now click [filename without extension] and enter AAAA2, then under kind of sundial select bifilar, and we will continue.

For a bifilar dial you have to enter values for the height of two threads. If these values are the same, you will just calculate a usual flat sundial, so choose two different values e.g. 30 for the X-thread and 20 for the Y-thread.

In the drawing, by default one thread is parallel to the x-axis (horizontal on the screen) and the other parallel to the y-axis (vertical on the screen), but you may rotate them by entering a value for "rotation". For this example we will choose rotation = 0 degrees.

You may choose other lines than the ones selected for the flat sundial AAAA, but for our example, lets keep the ones we used for AAAA.

Now [calculate and draw] the sundial.

Use shift, scale, and clip to edit the drawing to the final shape. The result can be seen in figure 9.

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Note 1: The main difference between this bifilar dial and the original AAAA dial is that all the points are stretched in the y direction.

Note 2: For bifilar dials, there are two lines at the the top of the drawing indicating the height of the two threads, instead of one line for the gnomon's length as in a flat sundial.

Note 3: A clipped dial is rescaled to 1:1 with corrected values for the gnomon or threads.

In the next example we will describe a bifilar dial on an inclining declining plane with equiangular hourlines. This is more complicated and some calculations have to be made.

Start a [New Sundial] with the name BBBB.

To begin with, we will need to find the equivalent latitude and the shift in the longitude where your dial's plane is horizontal, so we will temporarily select flat sundial to get some values we need.

With flat sundial selected, enter latitude 45, inclination 80, declination 20.

For this flat sundial the equivalent latitude is -32.11, its longitude correction is 23.43 and the angle of the substyle in respect to the Y-axis is -163.41.

Note at least the style height and the substyle angle of the dial as shown in the blue field.

Calculate the abs ( sin (style height) ) = 0.5315. We will use this value when calculating the height of the X-thread so as to produce equiangular hourlines.

Now select the dial type bifilar and we will continue our example.

To draw a bifilar dial with equiangular hourlines the relation between the height of the 2 threads must be: height_of_X-thread = height_of_Y-thread * abs ( sin (style height) ).

In addition, the 2 threads must be rotated to the angle of the substyle as determined for a usual flat dial.

We can now enter the data for our sundial.

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If you would like to explore some additional features of Zw2000, exit the program and start again.

At the new start the Utrecht dial appears again. Enjoy its simplicity.

Select [Load File] to open one of the saved dials, AAAA, AAAA2, or BBBB. Either the original dials or the clipped dials. The original dials can be scaled, shifted or colored as you want. The clipped dials cannot be shifted or scaled, but the layers can be switched on or off and colored.

You can make new clipped drawings of your original dials at any time.

By selecting [DXF], an original file as well as a clipped file can be exported as a .dxf file for use in cad programs such as Autocad , Turbocad or Deltacad. With your cad program you may add numerals and modify the drawing to your needs.

By selecting the [Clipboard] feature, you can copy a bitmap of the drawing on the screen to the clipboard so it can be pasted into other programs such as Paintshop.

[Pref] : This feature is used to adjust the aspect ratio on your screen. Load the file square.rlt. If the drawing of a square on your screen does not look like a square you may change the aspect ratio of the drawing. This has no affect on the data in your files, it only affects your screen. Figure 11 shows the screens for [Pref]

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There are two other features on the drawing screen which can only be applied to clipped drawings:

By selecting [Plot], a clipped dial also can be exported as a .plt file (hpgl format). .plt files can be used to send the dial to a printer, e.g. with the help of the program Printgl.

[Mult] : The data of a clipped drawing can be exported to a text file to have data available for making the real dial. Choose a multiplying factor to scale the gnomon or height of threads to the real dimensions of the gnomon. When applying [Mult] to a .clt file which you have clipped from a .rlt file that was created by another program, the layer names may be different from those assumed by Zw2000. Hence, the headings in the text file produced by [Mult] may be different as well.

Figure 12 shows the screen for [Mult].

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Any time you have a calculated dial on the screen, selecting [New Sundial] will bring up the Data Input screen with the data for the current dial already in place. This gives you the opportunity to edit a particular dial without entering all the data. If you do edit it, you may want to save it with a new filename.

If you select [New Sundial] when the Utrecht dial is on the screen you will get the data for the last calculated dial.

If you are on the Data Input screen and you choose [filename without extension] with the name of an existing dial, the data for that dial will become the current data. By doing this you are able to continue working with an existing dial.

Another possibility is to save the data for a specific dial as a default. Use the button [default] on the Data Input screen to save or reload your settings.

The input screen can be shown in 3 languages, English (default) , Dutch, or German. The drawing screen however only has English text on the buttons. Perhaps I will change this in the future.

The green text [points every 3 days] at the bottom left of the data input screen indicates that by default the program will calculate points for lines and curves with a 3 day interval. This can be changed to a one day interval by clicking the text. Selecting a one day interval will decrease the speed of the calculations and increase the size of the file on disk. This is a toggle - clicking the text again will return the interval to 3 days. For ordinary purposes it is recommended that you use 3 day intervals.

To the right of the [points every 3 days] option there is a checkbox which will give you the option to [  ]draw substyle for flat, non submerged, dials or [  ]draw threads for bifilar dials. Checking this option will put the appropriate line(s) in the drawing, and they can be manipulated on the [Settings] screen in layer L_Z. See figure 13 for these 2 options.

If too many lines have to be calculated, so many points have to be stored in the file that it cannot be saved any more. This will occur rapidly in submerged dials where all the lines are curves. Sometimes you will be unable to load a file with too many data points in it.

Note also that any time you re-enter the Data Input screen from the drawing screen the program returns to the default value for points every 3 days and the box for substyle or threads unchecked.

A third type of dial that may be calculated is the mirror dial.

All 3 types of sundials may also be calculated so that the whole dial, including the gnomon or threads, is submerged in water or another transparent medium. In this case the refraction index of the material must be entered. For water this is about 1.3333. It is always assumed that the surface of the transparent medium is horizontal.

An example of such a dial is shown in figure 14. It is a dial on an inclining, declining plane.

Another feature on the data input form is the [definitions] button. Clicking this will open a screen with the main gnomonic definitions I use in the program. These definitions are valid all over the world, no matter what hemisphere you are in.

You will also find them listed on the definitions page.

Figure 15 shows the definitions I use in this program for gnomon, style and substyle.

English-speaking people use the word gnomon to refer to the entire piece that casts the shadow, but in this document gnomon is used in its older and more traditional sense. Here the gnomon is a pin, perpendicular to the dial plane.

The last feature on the data input form is the button [print] which will print the constants of the dial to your printer. This will provide you a quick reminder as you work on your dial.

Let's return to the drawing screen and note the 2 buttons at the lower left.

The top one has a figure 8 on it. Clicking this button will bring up a dialog for drawing a graph for the Equation of Time and the Sun's Declination for a year in the period 1902 - 2202, with steps every 4 years. These 4 year steps yield a year in the middle of a leap year period.

This graph, as is shown in figure 16, only can be exported to the clipboard, however the lines without text are saved in a clipped file eot_decl.clt and can be reused.

The lower button has a square divided half black and half white. Clicking this button will bring up a dialog whereby a graph may be produced showing the hours that a selected plane will receive sunlight.

This graph as is shown in figure 17, also can only be exported to the clipboard, however the lines without text are saved in the clipped file time_lim.clt and can be reused.

Remark : For a horizontal sundial the red lines will not appear. They disappear beneath the blue lines.

Keep in mind that these last 2 features are separate programs that have no relation to the main program Zw2000.

New feature since version 1.1, November 2000

Notes:

System Requirements: Any version of Windows and a screen with a resolution of at least 800 x 600.
This version also work with Windows Vista for 64 bits computer.
However, the possibility to print the data of the dial isn't tested.

A mouse is also recommended, however most of the commands can be entered with the keyboard.

Files:
An original dial is saved in a .rlt file and has a related .rlq file.
A clipped dial is saved in a .clt file and has a related .clq file.

In the program directory you find the following .ini files:
zw2000_0.ini : values for the aspect ratio of the drawing.
zw2000_1.ini : value for the language used on the data input screen.

In each active directory you may find the following .ini files:
zw2000_2.ini : data for the last dial calculated in this directory.
zw2000_3.ini : data for a default dial in this directory.

The files eot_decl.clt, time_lim.clt and defin.txt are saved in the program directory.

Other programs have been published that output a .rlt file. These files can't be imported into Zw2000 version 2.0.

Enjoy the program and please give your comments.

Fer de Vries, Netherlands.
Date July 2009.

send an e-mail for any comment.

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To : De Zonnewijzerkring......The Dutch Sundial Society