Astronomy Picture of the Day today is an Analemma of the Moon
http://antwrp.gsfc.nasa.gov/apod/ap050713.html
Bob
AfterRoman dials with their vertical obelisk
type gnomons,
when did sundials withgnomons in parallel to
the planet's axis
first appear? Ifound an entry in the BSS
Glossary 2000
for the introduction of an armillary dial in 1598
by Valentin Pini.
Would he have been the first one to have
I don't
know whether tis is strictly "on topic" in relation to your question but on a
visit to Pompeii recently I was amazed by the sundial at the Temple of
Apollo.
This was
buried in 79AD and is far froma a "vertical obelisk type
dial"
A picture
can be found at:
