Re: Re: Any Wall Sundials On Irish Buildings

So Teak, are you thinking of incorporating a sundial into one of your projects?

I am thinking of one for a house wall — maybe even 3, for the E, S and W walls.

And it would be easy for an architect – using their CAD software to get image projection of the 24 x 15 degree equatorial dial grid onto any defined wall inclination – to set out the dial and then colour plot that pattern & its decoration effects precisely on A1 paper.

My planned dial also includes having a better means of getting local time without coarse inscribed tables on the dial or (worse) mentally making the equation of time correction oneself.
Something simple like a nick or small ball on the gnomon edge and then see where this mark’s shadow falls on a set of (pre-calculated and inscribed) equation of time correction curves for various times of the year .
The equation of time correction is almost symmetrical so half the possible shadow length contours can be used if the reader knows whether they’re in one half of the year or the other.

Materials.

Wood.
If used, would have to be as isotropic as possible. Hence plys or some carefully chosen wood with appropriate even expansion characteristics.
Never going to be as precise as metal or stone but agreeable to look at and paintable.

Metal.
Many decorative possibilities here, with polishing, masking & plating, anodising & dyeing (aluminium), anodising & interference colour effect (SS, titanium), lacquer cover, natural weathering oxide films (bronze), etc.
Big advantage with metal dial is the precision of its inscription and the possibility of being able to mount it easily on adjustable tilts so that the time may be set precisely and corrected later if needed.

Stone/Ceramic.
A precise layout pattern is a must here.
This will also be the most expensive to produce due to cost of ornamental sculptor’s time, doing all those small cuts with smaller machine tools and even handtools.
Also have to consider the protection of the dial from weathering effects.
But maybe the most impressive material in the end, if you imagine an old red sandstone dial like old farmhouses used to have with their quaint sun- and moon-faces.