A plotting Instrument for sundials on ir r e g u l a r surfaces Gérard Labrosse.

A plotting Instrument for

sundials on irregular surfacesGérard Labrosse

2

Introduction

Methodical put in function Indispensable presence of

the sun

3

Advantages

Two perpendiculary lasers

Possibility of lay out big sundials highly positioned

Not necessary to know the declination of the wall

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Latitude settings

12 intervals match to a graduated sector of 23°

Precision of 5 minutes of arc

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Billsticking of the hour angle H

Ball pushed by a coin (7,5°) Any other hour angle

6

Billsticking of the declination Solstices and equinoxes positioned with

3 holes: an axis with symbol

For any declination of the sun:the disc can be blocked with a small plastic stopper which is pusched with a screw (with a sun decoration)

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Horizontality adjustment An aluminium tray with 15,75" on each side   3 screws for adjustment

Double precise spirit level

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Alignment on the local meridian

A compass for a first rough alignment

A viewfinder with a lens and a target

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Drawing the hour lines

Adjust the position of the lower disc on the value of the hour angle (15° for 13h…)

Pivot the upper disc from the top to the bottom

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Drawing the diurn curves

Adjust the value of the sun declination value of the hour angle

You just have to pivot the upper part from left to right

11

Style installation

The style is positioned in a way that the laser point is visible on its end

12

Œuvres du Père Pardies

13

With a lamp

A plotting Instrument for

sundials on irregular surfacesGérard Labrosse