Calendar ground for analemmatic sundials
This article is mainly addressed to sundials designers and makers, and assuming the knowledge of the theory of analemmatic sundials. A lot of information may be googled, and some of it you can find in THEORY section of our site.
This photo of analemmatic sundials was made in Valencia.
Very nice sundials with firm construction and modern minimalistic design.
But photo itself illustrates the problem, which may be named
"standing at the right place".
To know sun time one should stand at the middle of the calendar ground. In all analemmatic sundials it is a meridian line. But, any calendar ground should have some calendar scaling on it. And in most cases it confuses.
Calendar ground in Valencia at closer look is below.
Traditionally, there are two calendar systems, used in annual scaling:
Gregorian and Zodiac. The last prevails in gnomonics, because
a zodiacal division is based on Sun's longitude. Zodiac scaling will be
symmetric with respect to meridian line. In Valencia we see Zodiac scaling,
but instead of the signs the civil dates for Zodiac months are indicated.
On the contrary, Georgian's scaling doesn't have Meridian's symmetry, but more understandable for mordern people. Look at the calendar ground of analemmatic sundials in Genk, Belgium.
In both cases confusion is possible, and only information panels nearby solve this problem.
So, a good design of the calendar ground should stimulate the person to stand at the right
The middle of the calendar ground in Valencia is marked with circles, and appropriate instructions are writen on info panel, but... As one can see on the photo at the begining, it does not help in some cases.
Just a few examples below, and much more can be found in the Internet.
Analemmatic sundials in Shelkovo, Russia (made by A. Boldyrev) have a combination of two scaling, both Georgian and Zodiac.
A card made for pupils in Habana in the form of analemmatic sundials with Georgian calendar. A variant with Zodiac is also exists, and can be seen in NEWS section.
Engraved tiles were used for analemmatic sundials made by "True Time Workshop" for Moscow school 1302. Scaling is zodiacal.
Acctually, if you don't read (and follow) instructions, accompanying most of
analemmatic sundials in public places, you may be confused.
Here we suggest another approach to the problem. Let us make caledar ground in so way, that it will be impossible, or inconvinient to stand improperly. Below is what we called calendar pedestal for analemmatic sundials. This idea was not implemented by True Time Workshop, but seems to be fruitful.
We'll appreciate any information about possible implementations of such "pedestal" construction. We are ready to cooperate with the makers and designers on the matter.