Singleton's azimuthal
Hi Mac: you wrote: >Hi John, > >As I was walking my exercise miles this morning, I found myself >wondering why you are thinking of doing an azimuthal dial at all, >given the problems of dealing with either a short shadow or a very >long vertical post gnomon. Why not follow John Singleton's notion >(p. 51, BSS Journal for Feb 2000) and use your normal taut wire pole >style? > >Have I missed something in the discussion? Maybe we all have. I think John Singleton's azimuthal will not work (except at noon, sunrise and sunset). I know this is a rather bold statement to make, but I think there is a general misconception that azimuthal dials can work with either a vertical gnomon or a polar axis gnomon as was originally suggested in an earlier discussion. This has always bothered me because it seemed impossible. If a polar axis works, then it would certainly solve the gnomon height problem. Rather than speculate, I did a simple experiment. Using a Spin drawing of an azimuthal for my location and an icepick for the gnomon, I quickly found out that the dial worked correctly when the icepick was vertical and became progressively worse as I tilted it towards the celestial pole. Now, I wonder what the theorists will say about this. I wish John Singleton had an e-mail, because I too wonder if I'm missing something. But since his dial is made for London, hopefully someone there will duplicate my experiment using the actual drawing in the BSS journal and let us know the results. John Carmichael p.s Sorry I already broke my promiss not to discuss azimuthal dials any more, but I couldn't resist this Luke's question!
Re: Singleton's azimuthal
Hello John, My answer to you yesterday wasn't complete. Lateron I understood your experiment with a "spin" drawing and you concluded that it didn't work when you placed a polar style on it. And I answered: Yes, it will work. Your conclusion is right. As such it won't work. What I meant to say is that such a type of dial may be constructed on any plane with any style and any type of scale of dates. But for each combination of course you have to calculate the right pattern for the hourlines. If you change one part you have to recalculate the pattern So in general you may construct infinit dials like these. Naming these dials is another problem. The suggestion by Gianni ( monofilar dial ) isn't the worst I think Happy dialling, Fer.Fer J. de Vries[EMAIL PROTECTED]http://www.iae.nl/users/ferdv/Eindhoven, Netherlandslat. 51:30 N long. 5:30 E- Original Message -From: John Carmichael <[EMAIL PROTECTED]>To: <sundial@rrz.uni-koeln.de>Sent: Thursday, February 24, 2000 7:06 PMSubject: Singleton's azimuthal> Hi Mac:>> you wrote:> >Hi John,> >> >As I was walking my exercise miles this morning, I found myself> >wondering why you are thinking of doing an azimuthal dial at all,> >given the problems of dealing with either a short shadow or a very> >long vertical post gnomon. Why not follow John Singleton's notion> >(p. 51, BSS Journal for Feb 2000) and use your normal taut wire pole> >style?> >> >Have I missed something in the discussion?>> Maybe we all have. I think John Singleton's azimuthal will not work(except> at noon, sunrise and sunset). I know this is a rather bold statement to> make, but I think there is a general misconception that azimuthal dialscan> work with either a vertical gnomon or a polar axis gnomon as wasoriginally> suggested in an earlier discussion. This has always bothered me becauseit> seemed impossible. If a polar axis works, then it would certainly solvethe> gnomon height problem.>> Rather than speculate, I did a simple experiment. Using a Spin drawing ofan> azimuthal for my location and an icepick for the gnomon, I quickly foundout> that the dial worked correctly when the icepick was vertical and became> progressively worse as I tilted it towards the celestial pole.>> Now, I wonder what the theorists will say about this. I wish JohnSingleton> had an e-mail, because I too wonder if I'm missing something. But sincehis> dial is made for London, hopefully someone there will duplicate my> experiment using the actual drawing in the BSS journal and let us know the> results.>> John Carmichael>> p.s Sorry I already broke my promiss not to discuss azimuthal dials any> more, but I couldn't resist Mac's question!>> Fer J. de Vries[EMAIL PROTECTED]http://www.iae.nl/users/ferdv/Eindhoven, Netherlandslat. 51:30 N long. 5:30 E
Re: Singleton's azimuthal
[EMAIL PROTECTED] (John Carmichael) writes: > >... Why not follow John Singleton's notion (p. 51, BSS Journal > > for Feb 2000) and use your normal taut wire pole style? > > > >Have I missed something in the discussion? > > Maybe we all have. I think John Singleton's azimuthal will not work (except > at noon, sunrise and sunset). I know this is a rather bold statement to > make, but I think there is a general misconception that azimuthal dials can > work with either a vertical gnomon or a polar axis gnomon as was originally > suggested in an earlier discussion. This has always bothered me because it > seemed impossible. If a polar axis works, then it would certainly solve the > gnomon height problem. > > Rather than speculate, I did a simple experiment. Using a Spin drawing of an > azimuthal for my location and an icepick for the gnomon, I quickly found out > that the dial worked correctly when the icepick was vertical and became > progressively worse as I tilted it towards the celestial pole. A dial with date rings (neither "azimuthal" nor "Dali" is quite the right name) can be designed for any gnomon, in particular for either a straight vertical gnomon or a straight polar gnomon, but any given dial plate will only work with its own gnomon. Your mistake was trying to use a "vertical drawing" with an polar gnomon. --Art
Re: Singleton's azimuthal
Hello John, Yes, it will work. In general a style in any direction may be used. Such a style is perpendicular to some plane and it measures the azimuth of that plane. ( which is not the sundial's plane ) So you may call it an azimuthal dial, however I don't know if this name is the best. Gianni Ferrari uses the name monofilar dial. Happy dialling, 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: John Carmichael <[EMAIL PROTECTED]> To: Sent: Thursday, February 24, 2000 7:06 PM Subject: Singleton's azimuthal > Hi Mac: > > you wrote: > >Hi John, > > > >As I was walking my exercise miles this morning, I found myself > >wondering why you are thinking of doing an azimuthal dial at all, > >given the problems of dealing with either a short shadow or a very > >long vertical post gnomon. Why not follow John Singleton's notion > >(p. 51, BSS Journal for Feb 2000) and use your normal taut wire pole > >style? > > > >Have I missed something in the discussion? > > Maybe we all have. I think John Singleton's azimuthal will not work (except > at noon, sunrise and sunset). I know this is a rather bold statement to > make, but I think there is a general misconception that azimuthal dials can > work with either a vertical gnomon or a polar axis gnomon as was originally > suggested in an earlier discussion. This has always bothered me because it > seemed impossible. If a polar axis works, then it would certainly solve the > gnomon height problem. > > Rather than speculate, I did a simple experiment. Using a Spin drawing of an > azimuthal for my location and an icepick for the gnomon, I quickly found out > that the dial worked correctly when the icepick was vertical and became > progressively worse as I tilted it towards the celestial pole. > > Now, I wonder what the theorists will say about this. I wish John Singleton > had an e-mail, because I too wonder if I'm missing something. But since his > dial is made for London, hopefully someone there will duplicate my > experiment using the actual drawing in the BSS journal and let us know the > results. > > John Carmichael > > p.s Sorry I already broke my promiss not to discuss azimuthal dials any > more, but I couldn't resist Mac's question! > >
Re: Singleton's azimuthal
Is Singleton's dial an azimuthal dial? Or is it a horizontal with the e.o.t. 'unwrapped'?
Singleton's azimuthal
Hi Mac: you wrote: >Hi John, > >As I was walking my exercise miles this morning, I found myself >wondering why you are thinking of doing an azimuthal dial at all, >given the problems of dealing with either a short shadow or a very >long vertical post gnomon. Why not follow John Singleton's notion >(p. 51, BSS Journal for Feb 2000) and use your normal taut wire pole >style? > >Have I missed something in the discussion? Maybe we all have. I think John Singleton's azimuthal will not work (except at noon, sunrise and sunset). I know this is a rather bold statement to make, but I think there is a general misconception that azimuthal dials can work with either a vertical gnomon or a polar axis gnomon as was originally suggested in an earlier discussion. This has always bothered me because it seemed impossible. If a polar axis works, then it would certainly solve the gnomon height problem. Rather than speculate, I did a simple experiment. Using a Spin drawing of an azimuthal for my location and an icepick for the gnomon, I quickly found out that the dial worked correctly when the icepick was vertical and became progressively worse as I tilted it towards the celestial pole. Now, I wonder what the theorists will say about this. I wish John Singleton had an e-mail, because I too wonder if I'm missing something. But since his dial is made for London, hopefully someone there will duplicate my experiment using the actual drawing in the BSS journal and let us know the results. John Carmichael p.s Sorry I already broke my promiss not to discuss azimuthal dials any more, but I couldn't resist Mac's question!
