Hi Peter-- Thanks for the reply and info. Yes, I hope that Fred Sawyer will post about the derivation of the construction of the Capuchin and Universal Capuchin dials.
Fred, would you paste some of your lecture material, about that, into a list e-mail here? Michael Ossipoff On Wed, May 10, 2017 at 10:33 PM, Peter Mayer <[email protected]> wrote: > Hi Michael, > > I've been hoping that Fred Sawyer would respond to your enquiry. At > last year's NASS Conference, Fred gave a talk on Rectilinear Altitude > Dials. It was, as always, a tour de force...and way over my head! But in > it Fred demonstrated the unity of Capuchin, Regiomantanus, Peter Apian, > etc. etc. plus his own earlier Nomographic Dial...as well as novel dials > based on the same principles. > > best wishes, > > Peter > > On 11/05/2017 01:46, Michael Ossipoff wrote: > > > Sure, analytic geometry verifies that the Universal Capuchin dial agrees > with the formula that relates time, altitude, declination and latitude. > > But that isn't how medieval astronomers &/or dialists arrived at the > construction of the Capuchin dials. > > Michael Ossipoff > > On Tue, May 9, 2017 at 4:13 PM, Michael Ossipoff <[email protected]> > wrote: > >> Thank you--Yes that's the article that I quoted, and from which I got the >> diagram that I posted here. >> >> That's the article that doesn't really explain anything. >> >> It shows a picture of a Capuchin dial (figure 1), and also a diagram of >> an orthographic projection of the celestial sphere (figure 2). Its >> explanation basically consists of saying that figure 2 looks like figure 1. >> >> But, for one thing, of course it doesn't. >> >> For one thing, >> >> 1. In figure 2, the parallel lines are parallel to the horizon. In figure >> 1, the parallel lines in the bottom half-circle are perpendicular to the >> direction of the sun. >> >> 2. In figure 2, the small circle to the left is centered within the sun's >> extreme diurnal positive and negative altitudes, at the depicted solar >> declination. >> >> ...but, in figure 1, it's the circle with the parallel lines is just >> centered at the middle of the page. >> >> 3. In figure 2, the sun is shown at a southern declination, something >> that is seemingly in disagreement with figure 1. >> >> But all that is aside from the fact that the article just doesn't give an >> explanation, other than its handwaving reference to the alleged similarity >> of figure 1 and figure 2. >> >> Anyway, yes, that's the article to which I was referring. So my question >> is, "What would be a genuine explanation and justification for the >> construction of the Capuchin and Universal Capuchin dials? >> >> Michael Ossipoff >> >> >> 2017-05-09 15:49 GMT-04:00 Putowsky via sundial <[email protected]>: >> >>> Diese Nachricht wurde eingewickelt um DMARC-kompatibel zu sein. Die >>> eigentliche Nachricht steht dadurch in einem Anhang. >>> >>> This message was wrapped to be DMARC compliant. The actual message >>> text is therefore in an attachment. >>> >>> ---------- Forwarded message ---------- >>> From: Putowsky <[email protected]> >>> To: Michael Ossipoff <[email protected]> >>> Cc: sundial list <[email protected]> >>> Bcc: >>> Date: Tue, 9 May 2017 21:49:58 +0200 >>> Subject: Re: Construction-Principle of Capuchin & Universal Capuchin >>> Dials??? >>> Here is the complete article. >>> >>> http://articles.adsabs.harvard.edu//full/1961JRASC..55...49S >>> /0000054.000.html >>> >>> [email protected] >>> >>> On May 9, 2017, at 8:50 PM, Michael Ossipoff <[email protected]> >>> wrote: >>> >>> I'm not asking about the *instructions *for constructing Capuchin and >>> Universal Capuchin dials. I'm asking about the principle, the explanation, >>> the justification, for their construction. >>> >>> Some websites have said or implied that it has to do with an >>> orthographic planisphere. I'm familiar with the use of a universal >>> planisphere, an azimuthal projection of the celestial sphere in >>> equatorial-aspect. ...but it isn't entirely clear how that relates to the >>> Capuchin dials. >>> >>> I found a handwaving explanation on the web. I've pasted its diagram, >>> and some of its "explanation", below in this e-mail. >>> >>> The explanation says that the diagram below, an orthographic projection >>> of the celestial-sphere, looks just like a Capuchin dial. And that's >>> supposed to be an explanation. >>> >>> So, how does an orthographic projection of the celestial-sphere lead to >>> a justification and explanation of the construction of a Capuchin or >>> Universal Capuchin dial? >>> >>> Can anyone here explain that? If so, the explanation would be >>> appreciated. >>> >>> Michael Ossipoff >>> >>> <image.png> >>> >>> --------------------------------------------------- >>> https://lists.uni-koeln.de/mailman/listinfo/sundial >>> >>> >>> --------------------------------------------------- >>> https://lists.uni-koeln.de/mailman/listinfo/sundial >>> >>> >>> >> > > > ---------------------------------------------------https://lists.uni-koeln.de/mailman/listinfo/sundial > > > -- > Peter Mayer > Department of Politics & International Studies (POLIS) > School of Social Scienceshttp://www.arts.adelaide.edu.au/polis/ > The University of Adelaide, AUSTRALIA 5005 > Ph : +61 8 8313 5609 <+61%208%208313%205609> > Fax : +61 8 8313 3443 <+61%208%208313%203443> > e-mail: [email protected] > CRICOS Provider Number 00123M > ----------------------------------------------------------- > > This email message is intended only for the addressee(s) > and contains information that may be confidential > and/or copyright. 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