Hello Mac, I have not found in Internet any image of the Baggio's sundial in Varese . I have written to him asking some photos and I will send them to whom is interested (obviously to you).
The photo that I have attached in my last message can appear strange because the meridian line (of the solar noon) doesn't cut the analemma (as we see in the image). This because the Longitude of Varese =8.83° and our TZ = 1h The distance among the two lines changes and its maximum value is = 59 cm. On the day in which the photo was taken the distance is around = 42 cm The pole (diameter 10 cm ) that supports the plate (tilted with an angle = latitude) is put on the prolongation of the meridian line (that of the solar noon) The web-site of Baggio is http://www.meridianevarese.it To note in http://www.meridianevarese.it/realizzazioni.html the photo " Brinzio" where it is visible a spherical nodus star-shaped, suspended to a cable (the analemma is 7-8 m high) Gianni Ferrari P.S. The shape of the Baggio's nodus is indeed equal to that of John Carmichael, but Baggio didn't certainly know it (it is not registered to this list) :-) ----- Original Message ----- From: "Mac Oglesby" <[EMAIL PROTECTED]> To: "Gianni Ferrari" <[EMAIL PROTECTED]> Cc: <[email protected]> Sent: Sunday, August 13, 2006 7:47 PM Subject: Re: Expanded Nodi Shadow Experiment Hello Gianni, Thanks for showing this application, and also for your contributions to this fascinating thread. Are there pictures anywhere on the internet which show the overall installation? It's not completely clear to me just where the nodus is located, relative to the analemma. Best wishes, Mac Oglesby >After a lots of theory.. a practical object :- ) > > > >I send attached the image of the nodus used by >the Italian dialist Roberto Baggio in a meridian >line built in 2003, in a square of the town of >Varese (northern Italy) > >The nodus is put at a height of 4 m and it is >made with a square plate of brass (side=25 >cm) containing a great hole (diameter 14 cm ) >and a central disk with the diameter = 4.5 cm, > fixed with metallic threads. > >On the 4 points the letters N,E,S,O are cut out (O=Ovest = West). > >The analemma is long 10.6 m and is made with 750 >marble tesserae of 3x3 cm . > >From the summer solstice to the equinoxes the >central disk gives a distinctly visible shadow: >the ratio (distance nodus-image / disk-diameter) >= 410/4 <108 > >From the equinoxes to the winter solstice the >image of the outer circle disappears (fully in >penumbra) because the shadow of the disk widens >and that of the inside ring approaches the >center. In these seasons as nodus the shadow of >the whole plate is used . Its center is easily >located using the symmetry of the structure. > > > >Gianni Ferrari > > >Attachment converted: Macintosh HD:Varese_Nodus.jpg (JPEG/«IC») (00275479) >--------------------------------------------------- >https://lists.uni-koeln.de/mailman/listinfo/sundial --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
