Before mechanical clocks, quartz wristwatches, and atomic clocks, there were sundials.
This earliest of timekeepers may have existed since prehistoric times - some archaeologists have conjectured that Great Britain's famed Stonehenge (~2500 BC) may have functioned as one gigantic sundial - but "portable" specimens have been dated to at least 1500 BC Egypt.
Most sundials operate by means of a graduated plate upon which a gnomon (pronounced NO-mon) casts a shadow that moves as the sun arcs across the sky. Sundials can be quite accurate, and there are some locales around the globe where sundials are still utilized as principal timekeepers. Many serious gardeners install sundials in places of honor in their gardens. And there is now a sundial on Mars (link)!
Made of materials like stone, brass, and bronze, more than a few sundials have survived the ravages of time and have become highly collectible. And because sundials are still being manufactured, collecting can still be a reasonably affordable hobby.
Sundials have such a long history that collectors have formed niche areas of interest. Especially collectible today are signed pieces by craftsmen old and new, pieces made of more fragile materials like porcelain or stained glass, and small portable sundials that could be carried in a pocket or small case for personal use.
Think that all sundials are similar to the "horizontal" type found in most gardens? Actually, dials come in a variety of designs - "vertical", "reflecting", etc. And for collectors who prefer something really different there are dials like the annosphere that doesn't need the sun to tell time, and even a "pocket watch" that looks like a miniature Stonehenge!
If you're hesitant to collect dials due to space limitation, don't worry. Pocket dials take up no more space than many other collectibles, and the garden-type dials display beautifully hanging on a wall like paintings or clocks!
Would you like to learn more about sundials? Then check out the resources listed below, and
"Sundials: An Illustrated History of Portable Dials," by Hester Higton
Link to book
"Sundials: Their Theory and Construction," by Albert Waugh
Link to book
British Sundial Society (link)
Informative site offers a newsletter, links, and a comprehensive section devoted to Formulae & Glossary.
Harvard University Department of the History of Science (link)
This is "Waywiser," the online database of Harvard's "Collection of Historical Scientific Instruments." Just Quick Search "sundial" to view over three dozen examples from their extensive collection.
National Maritime Museum (link)
Most of the approximately 400 sundials in the Museum's collection are available for viewing online here.
North American Sundial Society (link)
Publishes a quarterly journal, The Compendium. Check out the Construction, FAQs, and Links pages.
Stained Glass Sundials (link)
Includes etched glass, plastic, mosaic, and ceramic sundials. Check out the Image Archive (from 16th Century to present) and pictorial section on Design & Construction.
The Sundial Store (link)
Commercial site has many interesting sections about sundials. Check out the pages on "Sundial 'Furniture'" and "Portable Sundials".
Sundials on the Internet (link)
British site has lots of fun pages from "6 Simple Sundial Projects" to a "Solar Noon Calculator".