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Sundial layout options

Calcad displays the diagram of the sundial in the main window. There are many options, allowing you to choose between simplicity and accuracy-because the Earth's axis is tilted, a simple sundial with straight hour lines can give readings that are incorrect by up to 15 minutes, depending on the time of year. Calcad can draw curved hour lines that compensate for these seasonal variations, and diurnal arcs that show where to take the reading depending on the date.

Select which lines to include by the Hours, Arcs, Other and Shadow-caster menus:

o   Hours
  *  SubdivisionDraw the dotted half-hour, quarter-hour or 10-minute lines
  *  Hour linesDraw straight hour lines (the readings will need to be adjusted by the equation of time), shown in black
  *  RestrictionLimit the layout of the hour lines to the useful length, which depends on the shape of the shadow-caster
  *  S January-JuneDraw the curved hour lines for the period from December 21/22 to June 20/21, shown in blue
  *  Z July-December Draw the curved hour lines for the period from June 20/21 to December 21/22, shown in red

o   Arcs
  *  SignsDraw the arcs of the solstices, the equinoxes and at the beginning of each zodiac sign, shown in purple
  *  DateDraw the arc for the date specified in the input box in the Other tab
  *  January-JuneDraw an arc for the first day of the months from January to June. These are shown in blue and the dotted arc corresponds to January 1
  *  July-December Draw an arc for the first day of the months July to December. These are shown in red and the dotted arc corresponds to July 1

o   Other
  *  2 pointsShow the position of the 2 shadow points used to perform the calculations
  *  AxesDraw the axis system
  *  SquaresDisplay a grid of square boxes to make it easier to transfer curved lines on to the sundial. The Other tab of the input box allows you to choose the size of the squares
  *  HorizonDraw the horizon line
  *  Refraction Integrate the adjustment for refraction in the layout of curves. This is only possible if you have provided complete location information in the Place tab (latitude plus either half-day or longitude and time zone)
  *  ShadowShow the shadow of the style or the gnomon and enable its animation. If you have provided complete location information in the Place tab (latitude plus either half-day or longitude and time zone) the shadow is drawn according to the refraction effect
  *  Desktop sundialRun the "Desktop sundial" mode.

o   Shadow-caster
  *  Visible Display the shadow-caster, which will be represented lying on the sundial
  *  TypeShow the shadow-caster as style (triangle or trapezoid) or gnomon (single perpendicular bar)

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