Capricorn: Dec.22-Jan.29 The Sundial Primer
created by Carl Sabanski
Capricorn: Dec.22-Jan.29

Mr. Sun The Sundial Primer Index "Sunny Day U" Index Mr. Sun


CD Sundial Kit

Refraction Sundial: a dial invented in 1999 by M. Catamo & C. Lucarini. It has no gnomon,  but the sundial consists of a circular diffraction pattern which forms a bright, multicoloured diametrical line pointing at the Sun when viewed perpendicularly to the centre of the dial plate. Horizontal, altitude and equinoctial versions are possible. The dial plate is usually made from a CD 9 Compact disc), hence "CD dial".

Diffraction Grating: a plate with a set of closely spaced slits (usually parallel and equi-distant), which disperses incoming light into its constituent wavelengths (i.e. colours). The surface of a CD acts a circular reflection diffraction grating.

The CD sundial presented here is an equatorial sundial and is easy to make and fun to use.  Because you need to look perpendicularly to the centre of the dial plate this sundial includes only the top plate of the equatorial sundial. It will only work between the spring and fall equinoxes.

Figure 1 shows the Kit that you will use to make your own CD sundial. All you need to find is a CD. That shouldn't be too hard.

Figure 1: CD Sundial Kit

Figure 1: CD Sundial Kit (CAD)

We have made up two kits so that you can build a CD sundial for the Northern or Southern Hemisphere. All you need are scissors, cardboard, glue and tape. And a CD of course. If you would like to download a PDF file of the "CD Sundial Kit" just open the door that works for you. 

CD Sundial Kit - Northern Hemisphere CD Sundial Kit - Southern Hemisphere
Northern Hemisphere Southern Hemisphere

When you have completed the sundial all you have to do is set up and it will tell you solar time. Check out the equatorial sundial for instructions on how to install your CD sundial. It's exactly the same. 

Here's what the sundial will look like once you have finished making it. This one is located in the Northern Hemisphere and positioned for a latitude of 50.  It's pretty hard to simulate a CD in CAD, so because a picture is worth a thousand words...

CD Sundial

Northern Hemisphere - August

Happy Dialling!