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Sundial Design Software
| This page lists, first, all the programmes we know about
which have been recommended by members, and then others which we have
not had any feedback on. We welcome news of other programmes and will
include them here - it is very helpful if you can do a short review of
what they do.
New arrivals - welcomeIf you use any of these programmes, please let us know what you thought of them - others would find it helpful. Other programmes we have heard about are
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from you if you know of any others which we don't know about!. Thank
This part of this page originally appeared as an article by Harold Brandmaier in Vol 4, Number 4 (December 1997)of The Compendium, the journal of the North American Sundial Society
Sundial design consists of the determination of the hour-lines or equivalent time markers on the sundial surface, the position of the shadow producing object relative to that surface and the limits of operation of the sundial. Early design procedures were manual, either graphical constructions or, later, the solution of the equivalent analytical equations using tables of logarithms and trigonometric functions. During the last thirty years, the development of the scientific calculator, the later models of which are programmable, and of course the personal computer, considerably reduced the tedium of repetitive calculations. Most recently, computer aided drafting has become useful. This article is a brief summary of the capabilities of a number of computer programs currently available for sundial design.
The accompanying table lists the characteristics of each program, particularly the types of sundials each is capable of designing. The availability of these programs is:
ZONWVLAK - Internet download from http://www.iaehv.nl/users/ferdv/ or digital bonus with the December 1994 issue of The Compendium. (See also below)
SUNDIALS - Gianni Ferrari, Via Valdrighi 135, 41100 Moderna, Italy. E-Mail: email@example.com(See also below)
CADRAN - Pierre Joseph Dallet, 4 Rue des Fougeres, 19200 Ussel, France.
LAMONT - Volume 4, Number 1 of the disk version of The Compendium.
SHADOWS - Internet download from http://web.fc-net.fr/frb/sundials/shadows.html (See also below)
SUNDIALS CONSTRUCTOR - The Sail-Loft, Whitfords Yard, Fowey, Cornwall PL23 1BH, England.(See also below)
A complete evaluation of these programs including verification of the calculated results is beyond the scope of this article. However, the table allows a program to be chosen that best satisfies the sundial designer's requirements. To use the table, a few explanations are required. A "Y" indicates that the capability listed in the leftmost column exists for the program listed in the uppermost row. Other letters refer to the underlined letter in the leftmost column. While all named planar sundials with a style parallel to Earth's axis can be categorized as inclining / declining dials, a few of the programs include specific named dials. For example, vertical direct, vertical declining, polar and flat equatorial dials; these are noted in the table. SUNDIALS' monofilar category is unique. It considers sundials with shadows cast by any straight line on a flat surface with day-lines that are specified curves (e.g. circles and ellipses). Submerged dials are those whose faces are covered by a material whose refractive index is different from air - for example, water.
Only SUNDIALS and CADRAN are capable of designing non-planar sundials. In studying these programs, the author learned that the shadow for "hat" type cylindrical and conical dials is cast by the edge of a round flat plate perpendicular to the axis and concentric with the dial surface.
The on-line documentation accompanying each program is not extensive. Items that may be missing include coordinate system definition, symbol definition, the signs (+/-) of angles in either the program input or output, whether angles are in decimal degrees or hour-minute-second format and their precision, error messages and their interpretation, and sample designs to guide the designer. Further, unless the designer understands French, it is difficult to use a number of what may be useful options in CADRAN.
Of interest to most dialists are planar sundials, either inclining or declining or, less frequently, both. The writer used the data for the vertical sundial, declining East, on his garage wall to partially verify most of these programs. This sundial was designed using a program developed by the writer for a now obsolete computer. All the results compared favorably. More stringent tests might include a "Great Decliner" that faces almost but not quite due East or West, and a general inclining and declining dial that is parallel to Earth's axis, for example the dial on pages 340-1 of Moxon's "Mechanick Exercises or the Doctrine of Handy-Works". As a guideline, each program option that is to be used should be verified either by using the results from another program, data in the sundial references, or the results of a manual calculation if feasible.
Finally, the user of any of these programs should not hesitate to contact the program source for further information on which to base a selection or, once procured, for help in using the program.
Harold Brandmaier 63 Florence Road, Harrington Park, NJ 07640 firstname.lastname@example.org
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