Dear
All,
Could someone help
me with a definition of a 'Projection Sundial'.
- Couldn't find it
in the BSS Glossary.
- Folkard &
Ward 1996 "Sundials Australia" have included in their section on Projection
Sundials - The chapel sundial (Merton College, Oxford), a Sun Compass, a direct
sunlight through a hole onto analemmas on the horizontal ground, Monash
University Union Building- Melbourne Australia (wall mounted rod tipped by a
disk making shadows on analemmas on a wall), the Augustus Sundial from 9BC,
Ulugh Bek's Observatory, mirror sundials shining on analemmas on a roof, various
noon marks and a Scottish polyhedral 'lectern'
sundial.
The common factor
seems to be that the shadow (or light ray) approximates a point rather than
a segment.
Is Projection
Sundial a recognised term?
What is the
characteristic that Projection Sundials have that other sundials
don't?
David
Pratten
