Re: Gnomon Gap Puzzle
Hi Frank, Thanks for the Gnomon Gap Puzzle. Learnt a lot from it. That is what makes sundials interesting. Always something new to learn. Great for the northern hemisphere. Does the book include a printout for the southern hemisphere? When I printed the dial onto A4 paper. It did not print correctly. It was close to being a square image. Would a pdf version be better. Thanks, Roderick Wall. Original message From: Frank King Date: 3/1/19 11:48 pm (GMT+10:00) To: Sundial List Subject: Re: Gnomon Gap Puzzle Dear All, I have a simple rule with my puzzles: wait for a reply from Geoff Thurston and then reveal all. The time has come! In the recent spate of messages, both Bill Gottesman and Steve Lelievre were very close. Bill is the only person to suggest an azimuthal dial with vertical styles (which describes my design) but Steve's drawing (despite the polar styles) is remarkably close to my design too. The 'unusual space' is "The End-Flap of a Book" - not easy to guess! By arranging for the top and bottom edges of the front cover to serve as vertical gnomons, you can mark out an azimuthal dial on the end-flap. This way the user doesn't need to supply a gnomon, nor is there any need for any kind of pop-out gnomon. The sundial is shown in operation outdoors in the real sun at: http://www.cl.cam.ac.uk/users/fhk1/Sundials/GnomonGapDial.jpg This shows what the design looks like. There are many forms of azimuthal dial but, as one who enjoys astrolabes, I like stereographic projections. [OK, I do realise that my design uses the zenith as the centre of the projection and not the NCP!] In terms of 'looking good', this design hardly competes with the Nuremburg or Harvard dials or the dials in the stunning images that Sara has just sent us. We can all look forward to the Adler catalogue. Sadly, those dials look a bit expensive. The link above shows the upmarket version of my design and this costs 15 GBP but you do get a book bundled in at no extra charge! There are lots of pretty pictures of sundials inside. What about implementing the design for less than a dime? Well, a dime is about what it costs me to print out a sheet of paper, and all you have to do is to print out the following: http://www.cl.cam.ac.uk/users/fhk1/Sundials/DoubleGapDial.jpg This is intended for A4-paper. You may have to trim the edges if you use LETTER size. This shows what is hidden on the inside back cover of the book. That is where the early morning and late evening summer-time hours are found. All you have to do is to fold along the black straight line (a valley fold not a ridge fold), place the S-part flat on a horizontal table, and point the S to SOUTH [some users find this a bit surprising!]. You must arrange for the larger part to be perpendicular to the S-part. In summer, in the early morning and late afternoon, you have to place the larger part flat on the table; the edges of the S-part then serve as gnomons. This really is a working diptych sundial and they don't come any cheaper! Sadly it is designed for my latitude +52d 12m but anyone who has read this far is likely to be well equipped to adapt the design for another latitude. Adventurous readers can add the appropriate wiggles to the hour lines to deal with longitude offset and EoT. Maybe it would be best to design two such dials (one on each side of the paper), with December to June hour lines on one side and June to December hour lines on the other. In the unlikely event that you might want the up-market version (with book attached) please contact: Hallam Kindersley Very best wishes Frank --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Gnomon Gap Puzzle
Dear John, Many thanks for your seal of approval... > Bravo - two quarters of a double horizontal dial! A fair summary, but note that it doesn't suffer from the knife-edge gnomon bug that most double horizontal dials suffer from. Fancy going wrong at noon of all times of day. Grrr! The latest Compendium comes with an insert in which you can see Steve Lelievre and me, at either end of a piece of string, demonstrating the failings of a large knife-edge gnomon near Pittsburgh. This dial is in a burial ground so, maybe, it is trying to be some kind of metaphor? Very best wishes Frank --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Gnomon Gap Puzzle - wonderful
Dear Alastair, Many thanks for your kind words... > Your design is wonderful... I hope you enjoy the book. You ask... > ... have you come across the term 'azimuth > circles', how would you define this term? I have heard this term in several contexts. In an astronomical context, any great circle that runs from your local zenith via the horizon down to the out-of-sight nadir is sometimes called an azimuth circle. As it happens, I call this a vertical circle; that's just habit but see later. In another context, I actually OWN an azimuth circle... I have an army marching compass (magnetic) which has an annular ring supporting the glass cover. The instructions call this the "azimuth circle". There is a radial line on the glass marked in luminous paint! The idea is that if you want to march towards some distant point, you aim the body of the compass at that point and then twiddle the azimuth circle so that the radial line covers the large N for north on the compass card. This N is also in luminous paint. I expect the whole thing is radio-active! You then walk along (er, MARCH along) keeping the line on top of the N. A more common azimuth circle is the horizontal graduated ring on a theodolite which enables you to determine the difference in bearing between two terrestrial objects. More generically, an azimuth circle seems to be any ring which is mounted in a horizontal plane and which can either be twiddled round itself or it is fixed and something else rotates round within it. In my opening example this means the entire horizon is an azimuth circle; it runs round all the vertical circles. That's one reason I call them vertical circles rather than azimuth circles! Some technical terms can be confusing :-) I expect Mr Google can give you more examples. Very best wishes Frank --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Gnomon Gap Puzzle - wonderful
Hello Frank Your design is wonderful, I would not have guessed it exactly, specifically that it was an azimuth dial. I did imagine it was a dial with a double (or split) style. I will buy the book! A question for you and others, have you come across the term 'azimuth circles', how would you define this term? I will be grateful for information. Many thanks and very best wishes for 2019 Alastair Hunter Edinburgh, UK -Original Message- From: sundial [mailto:sundial-boun...@uni-koeln.de] On Behalf Of Frank King Sent: Thursday, 3 January, 2019 12:49 PM To: Sundial List Subject: Re: Gnomon Gap Puzzle Dear All, I have a simple rule with my puzzles: wait for a reply from Geoff Thurston and then reveal all. The time has come! In the recent spate of messages, both Bill Gottesman and Steve Lelievre were very close. Bill is the only person to suggest an azimuthal dial with vertical styles (which describes my design) but Steve's drawing (despite the polar styles) is remarkably close to my design too. The 'unusual space' is "The End-Flap of a Book" - not easy to guess! By arranging for the top and bottom edges of the front cover to serve as vertical gnomons, you can mark out an azimuthal dial on the end-flap. This way the user doesn't need to supply a gnomon, nor is there any need for any kind of pop-out gnomon. The sundial is shown in operation outdoors in the real sun at: http://www.cl.cam.ac.uk/users/fhk1/Sundials/GnomonGapDial.jpg This shows what the design looks like. There are many forms of azimuthal dial but, as one who enjoys astrolabes, I like stereographic projections. [OK, I do realise that my design uses the zenith as the centre of the projection and not the NCP!] In terms of 'looking good', this design hardly competes with the Nuremburg or Harvard dials or the dials in the stunning images that Sara has just sent us. We can all look forward to the Adler catalogue. Sadly, those dials look a bit expensive. The link above shows the upmarket version of my design and this costs 15 GBP but you do get a book bundled in at no extra charge! There are lots of pretty pictures of sundials inside. What about implementing the design for less than a dime? Well, a dime is about what it costs me to print out a sheet of paper, and all you have to do is to print out the following: http://www.cl.cam.ac.uk/users/fhk1/Sundials/DoubleGapDial.jpg This is intended for A4-paper. You may have to trim the edges if you use LETTER size. This shows what is hidden on the inside back cover of the book. That is where the early morning and late evening summer-time hours are found. All you have to do is to fold along the black straight line (a valley fold not a ridge fold), place the S-part flat on a horizontal table, and point the S to SOUTH [some users find this a bit surprising!]. You must arrange for the larger part to be perpendicular to the S-part. In summer, in the early morning and late afternoon, you have to place the larger part flat on the table; the edges of the S-part then serve as gnomons. This really is a working diptych sundial and they don't come any cheaper! Sadly it is designed for my latitude +52d 12m but anyone who has read this far is likely to be well equipped to adapt the design for another latitude. Adventurous readers can add the appropriate wiggles to the hour lines to deal with longitude offset and EoT. Maybe it would be best to design two such dials (one on each side of the paper), with December to June hour lines on one side and June to December hour lines on the other. In the unlikely event that you might want the up-market version (with book attached) please contact: Hallam Kindersley Very best wishes Frank --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Gnomon Gap Puzzle
Dear All, I have a simple rule with my puzzles: wait for a reply from Geoff Thurston and then reveal all. The time has come! In the recent spate of messages, both Bill Gottesman and Steve Lelievre were very close. Bill is the only person to suggest an azimuthal dial with vertical styles (which describes my design) but Steve's drawing (despite the polar styles) is remarkably close to my design too. The 'unusual space' is "The End-Flap of a Book" - not easy to guess! By arranging for the top and bottom edges of the front cover to serve as vertical gnomons, you can mark out an azimuthal dial on the end-flap. This way the user doesn't need to supply a gnomon, nor is there any need for any kind of pop-out gnomon. The sundial is shown in operation outdoors in the real sun at: http://www.cl.cam.ac.uk/users/fhk1/Sundials/GnomonGapDial.jpg This shows what the design looks like. There are many forms of azimuthal dial but, as one who enjoys astrolabes, I like stereographic projections. [OK, I do realise that my design uses the zenith as the centre of the projection and not the NCP!] In terms of 'looking good', this design hardly competes with the Nuremburg or Harvard dials or the dials in the stunning images that Sara has just sent us. We can all look forward to the Adler catalogue. Sadly, those dials look a bit expensive. The link above shows the upmarket version of my design and this costs 15 GBP but you do get a book bundled in at no extra charge! There are lots of pretty pictures of sundials inside. What about implementing the design for less than a dime? Well, a dime is about what it costs me to print out a sheet of paper, and all you have to do is to print out the following: http://www.cl.cam.ac.uk/users/fhk1/Sundials/DoubleGapDial.jpg This is intended for A4-paper. You may have to trim the edges if you use LETTER size. This shows what is hidden on the inside back cover of the book. That is where the early morning and late evening summer-time hours are found. All you have to do is to fold along the black straight line (a valley fold not a ridge fold), place the S-part flat on a horizontal table, and point the S to SOUTH [some users find this a bit surprising!]. You must arrange for the larger part to be perpendicular to the S-part. In summer, in the early morning and late afternoon, you have to place the larger part flat on the table; the edges of the S-part then serve as gnomons. This really is a working diptych sundial and they don't come any cheaper! Sadly it is designed for my latitude +52d 12m but anyone who has read this far is likely to be well equipped to adapt the design for another latitude. Adventurous readers can add the appropriate wiggles to the hour lines to deal with longitude offset and EoT. Maybe it would be best to design two such dials (one on each side of the paper), with December to June hour lines on one side and June to December hour lines on the other. In the unlikely event that you might want the up-market version (with book attached) please contact: Hallam Kindersley Very best wishes Frank --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Gnomon Gap Puzzle
Happy New Year, Frank, How about a T-shaped dial consisting of a vertical east dial backed by a vertical west dial and sharing a solid sloping roof whose edges act as the gnomons. The hour lines close to noon could be marked as a horizontal dial on the "floor" of the dial. I think that this would meet the noon gap requirement but I cannot think of a location that demands it. Best wishes, Geoff On Tue, 1 Jan 2019 at 08:50, Frank King wrote: > Dear All, > > Here is a little Dialling Puzzle to start > the New Year... > > We are all familiar with the term 'Noon Gap'. > On a simple horizontal sundial with a plate > gnomon, this is the gap on the dial plate > between the two vertical faces of the gnomon. > > On the dial plate, there are two lines for > 12 o'clock with the noon gap between. Often > this gap is left blank. Sometimes there is > a date or, perhaps, the maker's name. > > During the year just ended, I was asked to > design a dial which had to fit in a rather > unusual space. After a little thought, I > decided on a solution. In this... > > THE ENTIRE DIAL FITS INSIDE THE GNOMON GAP > > Question 1: What does the design look like? > > Question 2: Can this possibly look good? > > Question 3: What is the 'unusual space'? > > A Happy New Year to you all. > > Frank King > Cambridge, U.K. > > --- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Gnomon Gap Puzzle
Frank, May I have a second try at answering your quiz? I'm still not doing it for a nickel, though. My new suggestion would be much the same set-up as for my first suggestion, but this time I feel sure the dial face can be entirely within the noon gap area (that is, assuming the noon gap is defined as the area on the poleward side of the gnomon, and we're talking about a standard horizontal dial but with a very wide gnomon... This time, I suggest that the "underside" of the gnomon should be a plane mirror. The upper side of the gnomon is not involved, so can be decorated as you like. The left and right edges of the rectangular underside of the gnomon act as styles for an underslung dial that services azimuths -90 to 90, and also act as styles for a reflecting dial that services the remaining azimuths. All the hour lines are in the area between the styles and are on the polar side of the gnomon. Some lines serve double duty. At least, I think so - I can't get it entirely clear in my head but as I visualize them, the same lines are applicable to both the reflected and underslung dials. When the sun is on the polar side of the dial, it is read using the edge of the bright reflected area. When it's on the equator side, the dial is read using the edge of the shadow. I've posted a crude representation of what I mean at http://www.gnomoni.ca/temp/quiz.png (northern hemisphere) Steve --- https://lists.uni-koeln.de/mailman/listinfo/sundial
RE: Gnomon Gap Puzzle
Hi Frank, At the Adler Planetarium, there is a portable universal equatorial brass sundial (T-19) with a propped equatorial plate whose edges cast a shadow on a horizontal surface below. It works in a similar manner to the Nuremberg diptych Maciej pointed out. The same technique is used with some overhangs on polyhedral dials in the Adler, but these examples are for fixed latitudes. For instance, M-324, A-400, and M-322. Here is a link to some images. https://www.dropbox.com/sh/nb4abv7eb2uspb3/AACnDhwBf-L5QVcvaZrh3Deoa?dl=0 These sundials will all be pictured and described in the forthcoming volume of the Adler's sundial catalogue, which I have authored. The volume is in press! Cheers, Sara -Original Message- From: Frank King Sent: Wednesday, January 02, 2019 3:42 AM To: Schechner, Sara ; ml...@interia.pl Cc: Frank King ; sundial@uni-koeln.de Subject: Re: Gnomon Gap Puzzle Dear Maciej and Sara, Gosh. Those are really incredible dials. The Nested L-shapes of the chapter rings on the Jacques Le Marie dial are very cleverly set out. I wonder how big a market there was for this kind of dial! Maciej's description of a Nuremberg Diptych - The shadow was cast by the edges of the upper leaf of the dial - is quite close to what I have in mind. This would be fine in British Latitudes but as you move nearer to the equator you find yourself having to peer inside an ever-narrowing gap! Very best wishes Frank --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Gnomon Gap Puzzle
Hello Frank, Could the space be a north-south alley, street, or park between two buildings? The vertical sides of the buildings adjoining the space can be seen as two vertical gnomons for an azimuthal dial. You would lay out the morning hours to the west of the eastern building, and the afternoon hours to the east of the western building. You could scale the dials so the two halves touch in the center, or whatever arrangement that looks attractive. -Bill On Wed, Jan 2, 2019 at 3:44 AM Frank King wrote: > Dear Maciej and Sara, > > Gosh. Those are really incredible dials. > The Nested L-shapes of the chapter rings > on the Jacques Le Marie dial are very > cleverly set out. I wonder how big a > market there was for this kind of dial! > > Maciej's description of a Nuremberg > Diptych - The shadow was cast by the > edges of the upper leaf of the dial - > is quite close to what I have in mind. > > This would be fine in British Latitudes > but as you move nearer to the equator > you find yourself having to peer inside > an ever-narrowing gap! > > Very best wishes > > Frank > > --- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Gnomon Gap Puzzle
Dear Maciej and Sara, Gosh. Those are really incredible dials. The Nested L-shapes of the chapter rings on the Jacques Le Marie dial are very cleverly set out. I wonder how big a market there was for this kind of dial! Maciej's description of a Nuremberg Diptych - The shadow was cast by the edges of the upper leaf of the dial - is quite close to what I have in mind. This would be fine in British Latitudes but as you move nearer to the equator you find yourself having to peer inside an ever-narrowing gap! Very best wishes Frank --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Gnomon Gap Puzzle
Dear All, And this is it ! Remarkably large and ingenous nuremberg dial by Hans Troschel in which the shadow is cast by the two edges of the upper leaf and the tilt of the upper leaf to the proper latitude is set with the help of a foldable latitude arm visible to the right the lower leaf. The dial is seen in the upper right corner of the webpage: http://michel.lalos.free.fr/cadrans_solaires/autres_depts/paris/louvre_des_antiquaires/cs_louvre_antiquaires.html Thanks to Michael Lalos for including a photo of it in a report from exposition by Galerie Delalande. I have also traced another example of the simpler version of this dial, similar to Oxford example, but with two compasses (possibly for compositional purpose): http://www.antiquites-catalogue.com/piece/212001/cadran-multiple-en-diptyque/ Both simpler versions of the dial are older (Oxford MHS - dated 1586, French dealer - dated 1595) than the dial documented by Michael Lalos (dated 1614), so it must had taken a couple of years for Hans Troschel to come to the string-less gnomon solution ! Regards, Maciej Lose Od: "Frank King" Do: ml...@interia.pl; john.f...@keme.co.uk; steve.lelievre.can...@gmail.com; Wysłane: 16:41 Wtorek 2019-01-01 Temat: Re: Gnomon Gap Puzzle > Dear Maciej, John and Steve > > Congratulations on coming up with several > ideas. I should have asked your advice > several months ago! > > Although your ideas seem wildly different, > they all share elements of the actual design > which I shall reveal in due course. > > Maciej: I am most grateful to you for drawing > my attention to the Hans Troschel diptych dial. > I didn't know of this before and its design is > certainly (almost) confined by the noon gap. > This is getting very close to my thoughts. > > John: you ask... > > > Could you be designing a vertical dial for > > an interior south facing wall with a 'Velux' > > type window (or any rectangular glassed-in > > section) in the sloping ceiling above? > > This is less like my design but, although on > a different scale, it has features in common > with the Hans Troschel dial so it, too, is > on the right lines. > > > Alternatively could one use an unsupported > > sloping porch roof as an underslung gnomon... > > That would certainly work but I suspect there > would be a temptation to include markings > outside the gnomon gap. > > > But it would not be very weatherproof with > > no sides to the roof! > > Well, let's call it a sloping sun-shade such > as was once common on shop fronts in summer. > You could decorate the shop front with the > dial markings. In British latitudes the shade > would be very steeply sloping. The idea would > be fine in sub-tropical latitudes which have > more need of shade! > > Steve: I must study your arrangement in more > detail but, at first reading, you have a good > scheme which again shares elements of the > design I came up with! You will certainly > be surprised when you see the space that I > had to deal with :-) > > I might just add that my design can be > implemented for a total outlay of no more > than one US dime! Not all sundials are > mega-expensive!! > > More in due course! > > Frank > > --- https://lists.uni-koeln.de/mailman/listinfo/sundial
RE: Gnomon Gap Puzzle
Dear Frank, I love the solution that Maciej pointed out in the Troschel dial (MHS 70006) and want to add that I have seen on this also on polyhedral dials. In addition, Harvard has a double-string-gnomon inclining dial by Jacques Le Maire (CHSI 7416) (http://waywiser.fas.harvard.edu/objects/12220/inclining-doublestringgnomon-sundial?ctx=c7b5cc99-4010-4ef5-a0ef-a842c4c635e4=53) which is like the Troschel but portable for multiple latitudes. Happy New Year, Sara Sara J. Schechner Altazimuth Arts 42°36'N 71° 22'W West Newton, MA 02465 http://www.altazimutharts.com/ Sara J. Schechner, Ph.D. David P. Wheatland Curator of the Collection of Historical Scientific Instruments Lecturer on the History of Science Department of the History of Science, Harvard University Science Center 251c, 1 Oxford Street, Cambridge, MA 02138 Tel: 617-496-9542 | Fax: 617-495-3344 sche...@fas.harvard.edu |@SaraSchechner http://scholar.harvard.edu/saraschechner http://chsi.harvard.edu/ -Original Message- From: sundial On Behalf Of Frank King Sent: Tuesday, January 01, 2019 10:42 AM To: ml...@interia.pl; john.f...@keme.co.uk; steve.lelievre.can...@gmail.com Cc: sundial@uni-koeln.de Subject: Re: Gnomon Gap Puzzle Dear Maciej, John and Steve Congratulations on coming up with several ideas. I should have asked your advice several months ago! Although your ideas seem wildly different, they all share elements of the actual design which I shall reveal in due course. Maciej: I am most grateful to you for drawing my attention to the Hans Troschel diptych dial. I didn't know of this before and its design is certainly (almost) confined by the noon gap. This is getting very close to my thoughts. John: you ask... > Could you be designing a vertical dial for an interior south facing > wall with a 'Velux' > type window (or any rectangular glassed-in > section) in the sloping ceiling above? This is less like my design but, although on a different scale, it has features in common with the Hans Troschel dial so it, too, is on the right lines. > Alternatively could one use an unsupported sloping porch roof as an > underslung gnomon... That would certainly work but I suspect there would be a temptation to include markings outside the gnomon gap. > But it would not be very weatherproof with no sides to the roof! Well, let's call it a sloping sun-shade such as was once common on shop fronts in summer. You could decorate the shop front with the dial markings. In British latitudes the shade would be very steeply sloping. The idea would be fine in sub-tropical latitudes which have more need of shade! Steve: I must study your arrangement in more detail but, at first reading, you have a good scheme which again shares elements of the design I came up with! You will certainly be surprised when you see the space that I had to deal with :-) I might just add that my design can be implemented for a total outlay of no more than one US dime! Not all sundials are mega-expensive!! More in due course! Frank --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Gnomon Gap Puzzle
Dear Frank, I recall that I saw once a nuremberg diptych of quite similar design - but without a string gnomon, which could have been even closer to Your idea. The shadow was cast by the edges of the upper leaf of the dial, tilted to the proper latitude with the help of foldable latitude arm. I browsed my archives, unfortunately I was unable to find the image. It was a truly ingenous design ! Regards, Maciej Lose Od: "Frank King" Do: ml...@interia.pl; john.f...@keme.co.uk; steve.lelievre.can...@gmail.com; Wysłane: 16:41 Wtorek 2019-01-01 Temat: Re: Gnomon Gap Puzzle > Dear Maciej, John and Steve > > Congratulations on coming up with several > ideas. I should have asked your advice > several months ago! > > Although your ideas seem wildly different, > they all share elements of the actual design > which I shall reveal in due course. > > Maciej: I am most grateful to you for drawing > my attention to the Hans Troschel diptych dial. > I didn't know of this before and its design is > certainly (almost) confined by the noon gap. > This is getting very close to my thoughts. > > John: you ask... > > > Could you be designing a vertical dial for > > an interior south facing wall with a 'Velux' > > type window (or any rectangular glassed-in > > section) in the sloping ceiling above? > > This is less like my design but, although on > a different scale, it has features in common > with the Hans Troschel dial so it, too, is > on the right lines. > > > Alternatively could one use an unsupported > > sloping porch roof as an underslung gnomon... > > That would certainly work but I suspect there > would be a temptation to include markings > outside the gnomon gap. > > > But it would not be very weatherproof with > > no sides to the roof! > > Well, let's call it a sloping sun-shade such > as was once common on shop fronts in summer. > You could decorate the shop front with the > dial markings. In British latitudes the shade > would be very steeply sloping. The idea would > be fine in sub-tropical latitudes which have > more need of shade! > > Steve: I must study your arrangement in more > detail but, at first reading, you have a good > scheme which again shares elements of the > design I came up with! You will certainly > be surprised when you see the space that I > had to deal with :-) > > I might just add that my design can be > implemented for a total outlay of no more > than one US dime! Not all sundials are > mega-expensive!! > > More in due course! > > Frank > > --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Gnomon Gap Puzzle
Hello again, Frank, A quick postscript to my first answer ... I can also get my 4 sub-dials by using parallelograms arranged in NS planes at the sides of the dial face, and sitting on the horizontal dial surface. The skew of the parallelograms would be such that they provide polar styles, so that each provides one overshot and one undershot style. This arrangement is using two gnomons though - like the Troschel dial - so is really two separate dials drawn with overlapping dial faces, hence it doesn't conform to the "all in the noon gap" requirement. Steve On 2019-01-01 7:41 a.m., Frank King wrote: Steve: ...at first reading, you have a good scheme which again shares elements of the design I came up with! --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Gnomon Gap Puzzle
Dear Maciej, John and Steve Congratulations on coming up with several ideas. I should have asked your advice several months ago! Although your ideas seem wildly different, they all share elements of the actual design which I shall reveal in due course. Maciej: I am most grateful to you for drawing my attention to the Hans Troschel diptych dial. I didn't know of this before and its design is certainly (almost) confined by the noon gap. This is getting very close to my thoughts. John: you ask... > Could you be designing a vertical dial for > an interior south facing wall with a 'Velux' > type window (or any rectangular glassed-in > section) in the sloping ceiling above? This is less like my design but, although on a different scale, it has features in common with the Hans Troschel dial so it, too, is on the right lines. > Alternatively could one use an unsupported > sloping porch roof as an underslung gnomon... That would certainly work but I suspect there would be a temptation to include markings outside the gnomon gap. > But it would not be very weatherproof with > no sides to the roof! Well, let's call it a sloping sun-shade such as was once common on shop fronts in summer. You could decorate the shop front with the dial markings. In British latitudes the shade would be very steeply sloping. The idea would be fine in sub-tropical latitudes which have more need of shade! Steve: I must study your arrangement in more detail but, at first reading, you have a good scheme which again shares elements of the design I came up with! You will certainly be surprised when you see the space that I had to deal with :-) I might just add that my design can be implemented for a total outlay of no more than one US dime! Not all sundials are mega-expensive!! More in due course! Frank --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Gnomon Gap Puzzle
For Q1, my solution would be a bit like the set up already suggested by Maciej Lose from Hans Troschel. Instead of having two wires in a diptych, I would use a rectangular sheet of material. It would be set up with one pair of opposite edges on an East-West line, and the other pair parallel to the polar axis. The east and west edges then each act as a style for an undershot and an overshot sub-dial, giving me four sub-dials in total, all horizontals. Two are on the north side of the gnomon and 2 are south of it. Assuming northern hemisphere then: The eastern style overshot works for solar azimuth <= -90 The eastern style undershot works for solar azimuth -90 to 0 The western style undershot works for solar azimuth 0 to 90 The western style overshot works for solar azimuth >= 90 With the right size and aspect ratio for the rectangle then the sub-dial faces need not overlap, and only one face sees the sun at any instant, so there's no confusion about which face to use...does this solution count as being entirely within the noon gap, though? For Q2, of course I say yes. For Q3: I have absolutely no idea what Frank's space is, but I think my solution would fit well around a ground-mounted solar panel array - they're arranged East-West and poleward, aren't they? Steve On 2019-01-01 12:50 a.m., Frank King wrote: Dear All, Here is a little Dialling Puzzle to start the New Year... We are all familiar with the term 'Noon Gap'. On a simple horizontal sundial with a plate gnomon, this is the gap on the dial plate between the two vertical faces of the gnomon. On the dial plate, there are two lines for 12 o'clock with the noon gap between. Often this gap is left blank. Sometimes there is a date or, perhaps, the maker's name. During the year just ended, I was asked to design a dial which had to fit in a rather unusual space. After a little thought, I decided on a solution. In this... THE ENTIRE DIAL FITS INSIDE THE GNOMON GAP Question 1: What does the design look like? Question 2: Can this possibly look good? Question 3: What is the 'unusual space'? A Happy New Year to you all. Frank King Cambridge, U.K. --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Gnomon Gap Puzzle
Dear Frank, For your question 3: Could you be designing a vertical dial for an interior south facing wall with a 'Velux' type window (or any rectangular glassed-in section) in the sloping ceiling above? I would have thought it would work and could be as attractive as you cared to make it! But I am not sure if that adheres to your spec of being in the noon gap unless you accept the glass as being a conceptual underslung gnomon. Alternatively could one use an unsupported sloping porch roof as an underslung gnomon, with the delineation in the area above the door? But it would not be very weatherproof with no sides to the roof! Happy New Year, John Foad -Original Message- From: Frank King Sent: Tuesday, January 1, 2019 8:50 AM To: sundial@uni-koeln.de Subject: Gnomon Gap Puzzle Dear All, Here is a little Dialling Puzzle to start the New Year... We are all familiar with the term 'Noon Gap'. On a simple horizontal sundial with a plate gnomon, this is the gap on the dial plate between the two vertical faces of the gnomon. On the dial plate, there are two lines for 12 o'clock with the noon gap between. Often this gap is left blank. Sometimes there is a date or, perhaps, the maker's name. During the year just ended, I was asked to design a dial which had to fit in a rather unusual space. After a little thought, I decided on a solution. In this... THE ENTIRE DIAL FITS INSIDE THE GNOMON GAP Question 1: What does the design look like? Question 2: Can this possibly look good? Question 3: What is the 'unusual space'? A Happy New Year to you all. Frank King Cambridge, U.K. --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Gnomon Gap Puzzle
Dear Frank, I'm not sure if this follows Your idea, but I think the the answer, by Hans Troschel, is in the collection of History of Science Museum in Oxford. Unfortunately no direct link is possible, so one has to use database search to find it: https://www.hsm.ox.ac.uk/database Diptych Dial, by Hans Troschel, Nuremberg, 1586 Inventory Number: 70006 And it certainly looks very conceptual and sophisticated, though the idea is incorporated into lower leaf - horizontal dial - only. If we look little wider, a crescent dial might be considered a "noon gap" equinoctial sundial as well ! Happy New Year, Maciej Lose Od: "Frank King" Do: sundial@uni-koeln.de; Wysłane: 9:51 Wtorek 2019-01-01 Temat: Gnomon Gap Puzzle > Dear All, > > Here is a little Dialling Puzzle to start > the New Year... > > We are all familiar with the term 'Noon Gap'. > On a simple horizontal sundial with a plate > gnomon, this is the gap on the dial plate > between the two vertical faces of the gnomon. > > On the dial plate, there are two lines for > 12 o'clock with the noon gap between. Often > this gap is left blank. Sometimes there is > a date or, perhaps, the maker's name. > > During the year just ended, I was asked to > design a dial which had to fit in a rather > unusual space. After a little thought, I > decided on a solution. In this... > > THE ENTIRE DIAL FITS INSIDE THE GNOMON GAP > > Question 1: What does the design look like? > > Question 2: Can this possibly look good? > > Question 3: What is the 'unusual space'? > > A Happy New Year to you all. > > Frank King > Cambridge, U.K. > > --- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Gnomon Gap Puzzle
Dear All, Here is a little Dialling Puzzle to start the New Year... We are all familiar with the term 'Noon Gap'. On a simple horizontal sundial with a plate gnomon, this is the gap on the dial plate between the two vertical faces of the gnomon. On the dial plate, there are two lines for 12 o'clock with the noon gap between. Often this gap is left blank. Sometimes there is a date or, perhaps, the maker's name. During the year just ended, I was asked to design a dial which had to fit in a rather unusual space. After a little thought, I decided on a solution. In this... THE ENTIRE DIAL FITS INSIDE THE GNOMON GAP Question 1: What does the design look like? Question 2: Can this possibly look good? Question 3: What is the 'unusual space'? A Happy New Year to you all. Frank King Cambridge, U.K. --- https://lists.uni-koeln.de/mailman/listinfo/sundial
