Hello Fer,
I made the drawing for my Lat (approx. 36 degs.) and was able to notice
that for my location a complete coverage couldn't be obtained but I
hadn't gone further to find where (or if) this limitation disappears, so
thank you for doing so. The image you sent says it all, this has been a
very interesting thread.
Regards,
Luke
"fer j. de vries" wrote:
>
> Hi Luke,
>
> I copied your drawing and I am "glad" you made a drawing for a latitude
> lower then 47 degrees.
>
> I added in red the sun's beam at noon at summer solstice and you may see
> that the beam is reflected in the wrong direction as John wrote.
>
> The grey line between is the normal to the mirror's plane.
>
> At higher latitudes this problem disappears, however, at latitudes lower
> then
> 47 degrees, some time of the year, a spot of light won't reach the ceiling.
>
> Greetings, Fer.
>
> Fer J. de Vries
> [EMAIL PROTECTED]
> http://www.iae.nl/users/ferdv/
> Eindhoven, Netherlands
> lat. 51:30 N long. 5:30 E
>
> ----- Original Message -----
> From: "Luke Coletti" <[EMAIL PROTECTED]>
> To: "Anselmo Pérez Serrada" <[EMAIL PROTECTED]>
> Cc: "Sundial, Mailinglist" <sundial@rrz.uni-koeln.de>
> Sent: Sunday, January 06, 2002 6:03 PM
> Subject: Re: Polar ceiling sundial
>
> >
> > I thought I might share a simple drawing (URL below) that illustrates
> > Anselmo's idea. In the drawing the Sun is "on" the Equator so the angle
> > of the Solar rays onto the respective surfaces (polar dial plate and
> > ceiling) is 90deg. However, it can be seen that this relation holds
> > throughout the year. The point of the projection disappearing with
> > southern solar declination values, I think is valid but the extent
> > should vary. Still, I can't yet imagine how complete coverage can be
> > practically obtained. Now, I wonder further if a mirrored surface can be
> > described such that the hour lines are equidistant? I think I know,
> > anyone have any thoughts?
> >
> >
> > ftp://ftp.gcstudio.com/pub/sundial/ceiling.pdf
> >
> >
> > Regards,
> >
> > Luke
> >
>
> ------------------------------------------------------------------------
> Name: ceiling3.gif
> ceiling3.gif Type: GIF Image (image/gif)
> Encoding: base64
