Hi all,
This link I think is a good way of showing. How we can understand how
sundials work. A sundial is a mechanical clock. Sundials are geared to
the largest clock in the world, Earth. Look at it from a mechanical
point of view on a spinning Earth.
Draw the earth and cut out paper sundials and place them at different
Longitudes and see what wedge is needed to keep the style parallel to
the axis of the Earth.
https://www.dropbox.com/s/5loieb818s2dr9o/CCF%20Relocating%20a%20sundial%204%20April%202023.pdf?dl=0
You can also understand how sundials work in the southern hemisphere.
The sun still comes up in the East and sets in the West.
Roderick
On 4/04/2023 12:03 pm, Michael Ossipoff wrote:
That surprises me too. I’d have expected that the only differences
would be that the dial is numbered counterclockwise, & that north & &
south are replaced with poleward & equatorward.
On Mon, Apr 3, 2023 at 16:47 Steve Lelievre
<steve.lelievre.can...@gmail.com> wrote:
Hi, Roderick,
My home internet connection is still non-functional so I can't fix
it yet, but it does seem that I will have to add an extra test to
handle southern hemisphere locations and reducing latitudes.
Actually, I originally had a southern hemisphere check in there
but took it out after convincing myself the same frame of
reference (x axis east, y axis north, z up) applied to the
spherical trigonometry irrespective of hemisphere. Ho hum.
Steve
On 2023-04-03 6:45 a.m., Rod Wall wrote:
Hi Steve,
For both examples below with all sundials at the same Longitude.
The instructions indicate:
Place the wedge-sundial assembly on a horizontal surface in a
nice sunny location. *Start with the higher end of the wedge to
the north* and the sides aligned on a north-south line and the
sharp edge should be on an east-west line.
Example 1:
If you have a sundial that was designed for Latitude -20 deg. And
relocate it at Latitude -50 deg.
Would you start with the higher end of the 30 deg wedge to the
North. Or would it be to the South?
*****
Example 2:
If you have a sundial that was designed for Latitude 50 deg. And
relocate it at 20 deg.
Would you start with the higher end of the 30 deg wedge to the
North. Or would it be to the South?
*****
Please correct me if I am wrong. I think that both examples would
be to the South.
Roderick.
---------------------------------------------------
https://lists.uni-koeln.de/mailman/listinfo/sundial
---------------------------------------------------
https://lists.uni-koeln.de/mailman/listinfo/sundial
