Fabio
Quite brilliant ! That is a tour-de-force in programming.
Best
Kevin

Kevin Karney, MA JP
Freedom Cottage, Llandogo, Monmouth NP25 4TP.
Phone 01594 530 595 Mobile 07595 024 960

> On 19 Jun 2015, at 22:44, Fabio nonvedolora <[email protected]> 
> wrote:
> 
> Hi all
>  
> I’ve just finished a new paper sundial, it is available as app 41, 
> www.sundialatlas.eu/atlas.php?app=41 
> <http://www.sundialatlas.eu/atlas.php?app=41>
>  
> It is like an hemi-sphere but realized with an half truncated icosahedron.
> To simulate the sphere I used this archimedean solid, also known as 
> fullerene, with 32 faces: 12 pentagons and 20 hexagons.
> It is also rendered with the image of the Earth (image credit of NASA – 
> Goddard Space Flight Center)
>  
> Setted any coordinates, the app turns the solid so that the correspondent 
> point becomes the lower point, on the vertical axis trough the center of the 
> solid, then it dissects the solid with an horizontal plane to get the pseudo 
> hemisphere.
> The app returns a pdf of 3 pages. The 1st with the section, the 2nd with the 
> development of the half solid and the 3th with the basement and the gnomon.
>  
> The edge of the gnomon reaches the center of the solid and shows the time in 
> the concave pseudo hemi-sphere where  there are also drawn the hour lines.
> The edge of the shadow shows the time but also the point on the Earth where, 
> moment by moment, the Sun is at zenith.
>  
> The algorithm is quite complex, the time to get the pdf may be about 18 
> seconds (server time) for half analemma every hour to about 72 seconds for 
> the whole analemma every 5 minutes (not very useful). A common case of half 
> analemma every 10 minutes require about 30 seconds.
>  
> Important note: the browsers have embedded a pdf reader to show these files 
> but they are not very accurate. May be you see lines slightly out of position 
> or you don’t get printed the dotted lines. The solution is very simple, save 
> the pdf in your computer, then open the file with Acrobat Reader, it is fully 
> able to show and print the whole content.
>  
> On the top face you can also read the amplitude and the daylight arc.
>  
> I verified the app with many locations, everything seems ok but your reports 
> will be welcome.
>  
> Enjoy the summer solstice on app 41, ciao Fabio
>  
> <hemi-truncated-icosahedron[1].jpg>
>  
> Fabio Savian
> [email protected]
> www.nonvedolora.eu
> Paderno Dugnano, Milano, Italy
> 45° 34' 10'' N, 9° 10' 9'' E, GMT+1 (DST +2)
> ---------------------------------------------------
> https://lists.uni-koeln.de/mailman/listinfo/sundial
> 

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