In article ,
Stewart Robert Hinsley wrote:
In message , Martin Brown
writes
Kay wrote:

Otherwise it could read up to 30 minutes out of sync with reality. You
need to know the correction for apparent solar noon for your longitude
and date. The seasonal analemma curve is very beautiful.

http://solar-center.stanford.edu/art/analemma.html

Well made sundials have a small table of corrections or a devisouly
shaped gnomon to allow for this.

And presumably to take advantage of the deviously shaped gnomon have to
be precisely aligned?

uk.rec.gardening maintains its tradition of gnomic utterances :-)


Regards,
Nick Maclaren.