Re: Request for information about a type of altitude dial
Hi Steve et al, It's usually just called a disc dial. I don't think the example shown is latitude-adjustable: the suspension point is fixed. All the historical ones I've seen are single latitude devices. Only the occulus is adjustable, for date (declination). Earlier examples had the hour points set on a concentric circle which meant that they were very inaccurate at some times of the year - the extension lobe on this one is an empirical attempt to improve things. The mathematics are dubious. The earliest versions seem to be 16th century and there are quite a number from the 17th. I have one along similar lines found by a metal detectorist in Norfolk (UK). Regards, John Dr J Davis Flowton Dials http://www.flowton-dials.co.uk/ BSS Editor http://www.sundialsoc.org.uk/bulletin.php From: Steve Lelievre steve.lelievre.can...@gmail.com To: sundial@uni-koeln.de sundial@uni-koeln.de Sent: Sunday, 1 June 2014, 23:13 Subject: Request for information about a type of altitude dial Hi folks, http://www.pinterest.com/pin/301178293801331061/ What type of dial is this; I realize it's a form of altitude dial, but is there a specific name for it? The accompanying note states that the dial can be adjusted for latitude by moving the attachment point. I don't understand which part of the mechanism does that. Can anyone explain it for me? Lastly, I'm appreciate references for articles or webpages that discuss these dials - history and mathematics. Thanks, Steve --- https://lists.uni-koeln.de/mailman/listinfo/sundial--- https://lists.uni-koeln.de/mailman/listinfo/sundial
RE: Request for information about a type of altitude dial
There has been some confusion in the discussion so far. Here is my take: The sundial pictured is called a “vertical disk dial.” It is an altitude sundial. The example pictured is similar to one at CHSI (inv. 7270) signed “I W” with a punch mark of a crown and date 1672. It is for latitude 52° 35'. Most of the vertical disk dials are for single latitudes, and have a single suspension point. However, a few try to be adjustable for latitude. At Harvard, an example is inv. 7264, which is signed and dated “ P. L. K. / 1755.” I will tweet images of them and post them in this Dropbox: https://www.dropbox.com/sh/9qg1p0kejm3o842/AACoYez5bVtRU5JhPJuJgOK8a 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 Department of the History of Science, Harvard University Science Center 251c, 1 Oxford Street, Cambridge, MA 02138 Tel: 617-496-9542 | Fax: 617-496-5932 | sche...@fas.harvard.edu http://scholar.harvard.edu/saraschechner http://chsi.harvard.edu/ On Sun, Jun 1, 2014 at 6:13 PM, Steve Lelievre steve.lelievre.can...@gmail.commailto:steve.lelievre.can...@gmail.com wrote: Hi folks, http://www.pinterest.com/pin/301178293801331061/https://urldefense.proofpoint.com/v1/url?u=http://www.pinterest.com/pin/301178293801331061/k=AjZjj3dyY74kKL92lieHqQ%3D%3D%0Ar=Y3uaNkd%2BN%2BBEMo7BAxbEQqOqpMk6uxYnCJsB4uxugzo%3D%0Am=izSTWMgNnFv8DfKU%2Bd249F%2B%2FyJSDHvIkXOyVUqkC8%2FU%3D%0As=7631973f481f1363e8d75a48591133eaed99295b1faf9d05a8f4a1ea4c25175d What type of dial is this; I realize it's a form of altitude dial, but is there a specific name for it? The accompanying note states that the dial can be adjusted for latitude by moving the attachment point. I don't understand which part of the mechanism does that. Can anyone explain it for me? Lastly, I'm appreciate references for articles or webpages that discuss these dials - history and mathematics. Thanks, Steve --- https://lists.uni-koeln.de/mailman/listinfo/sundialhttps://urldefense.proofpoint.com/v1/url?u=https://lists.uni-koeln.de/mailman/listinfo/sundialk=AjZjj3dyY74kKL92lieHqQ%3D%3D%0Ar=Y3uaNkd%2BN%2BBEMo7BAxbEQqOqpMk6uxYnCJsB4uxugzo%3D%0Am=izSTWMgNnFv8DfKU%2Bd249F%2B%2FyJSDHvIkXOyVUqkC8%2FU%3D%0As=dcc654938564a18e96ec2bb9f94d253a409277009b33d3b5467c6486ffb43f43 --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Request for information about a type of altitude dial
Hi folks, http://www.pinterest.com/pin/301178293801331061/ What type of dial is this; I realize it's a form of altitude dial, but is there a specific name for it? The accompanying note states that the dial can be adjusted for latitude by moving the attachment point. I don't understand which part of the mechanism does that. Can anyone explain it for me? Lastly, I'm appreciate references for articles or webpages that discuss these dials - history and mathematics. Thanks, Steve --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Request for information about a type of altitude dial
I don't know the name, but I believe the moveable attachment point is where the hanging loop clamps to the dial plate. Moving that will rotate the dial and altitude scale relative to vertical. Dave Sent from my iPhone On Jun 1, 2014, at 3:13 PM, Steve Lelievre steve.lelievre.can...@gmail.com wrote: Hi folks, http://www.pinterest.com/pin/301178293801331061/ What type of dial is this; I realize it's a form of altitude dial, but is there a specific name for it? The accompanying note states that the dial can be adjusted for latitude by moving the attachment point. I don't understand which part of the mechanism does that. Can anyone explain it for me? Lastly, I'm appreciate references for articles or webpages that discuss these dials - history and mathematics. Thanks, Steve --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Request for information about a type of altitude dial
Dave, That's the point I'm struggling to understand. I'm assuming a chain is used to suspend the dial in use, but wouldn't it adjust itself to bring the centre of gravity back under the point of suspension - effectively making it impossible to rotate the dial face? Steve On 01/06/2014 7:36 PM, David Bell wrote: I don't know the name, but I believe the moveable attachment point is where the hanging loop clamps to the dial plate. Moving that will rotate the dial and altitude scale relative to vertical. Dave Sent from my iPhone On Jun 1, 2014, at 3:13 PM, Steve Lelievre steve.lelievre.can...@gmail.com wrote: Hi folks, http://www.pinterest.com/pin/301178293801331061/ What type of dial is this; I realize it's a form of altitude dial, but is there a specific name for it? The accompanying note states that the dial can be adjusted for latitude by moving the attachment point. I don't understand which part of the mechanism does that. Can anyone explain it for me? Lastly, I'm appreciate references for articles or webpages that discuss these dials - history and mathematics. Thanks, Steve --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Request for information about a type of altitude dial
The benefit of an altitude dial is that it does need to be aligned with the polar axis. With that concept in mind then a latitude adjusted altitude dial is not feasible. However, if one gives up that benefit, and takes an altitude dial and then tilting it towards the pole, or away from it, in other words now aligning it with true north or true south, then the altitude dial will work at the adjusted new latitude. I have had fun with doing this with the shepherd dial. Some interesting dial plates can be generated that one would assume could never possibly work when so adjusted. However, they do. Simon Simon Wheaton-Smith www.illustratingshadows.com Phoenix, Arizona, W112.1 N33.5 From: Bill Gottesman billgottes...@comcast.net To: Steve Lelievre steve.lelievre.can...@gmail.com Cc: sundial@uni-koeln.de sundial@uni-koeln.de Sent: Sunday, June 1, 2014 3:35 PM Subject: Re: Request for information about a type of altitude dial Neat dial. I don't know what it is called, but I like it and it's clever pinhole date aperture. I suspect the note about attachment point and latitude is incorrect. I am not aware of any altitude dial that is adjustable for latitude (and still be mathematically correct). If there are any, I do not think this is one of them. -Bill On Sun, Jun 1, 2014 at 6:13 PM, Steve Lelievre steve.lelievre.can...@gmail.com wrote: Hi folks, http://www.pinterest.com/pin/301178293801331061/ What type of dial is this; I realize it's a form of altitude dial, but is there a specific name for it? The accompanying note states that the dial can be adjusted for latitude by moving the attachment point. I don't understand which part of the mechanism does that. Can anyone explain it for me? Lastly, I'm appreciate references for articles or webpages that discuss these dials - history and mathematics. Thanks, Steve --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Request for information about a type of altitude dial
* The benefit of an altitude dial is that it does need to be aligned with the polar axis. With that concept in mind then a latitude adjusted altitude dial is not feasible. However, if one gives up that benefit, and takes an altitude dial and then tilting it towards the pole, or away from it, in other words now aligning it with true north or true south, such that at the new latitude, the dial is aligned in space matching that alignment of its design latitude, then the altitude dial will work at the adjusted new latitude. I have had fun with doing this with the shepherd dial. Some interesting dial plates can be generated that one would assume could never possibly work when so adjusted. However, they do. I have a three page article on my web site, less than 1mb in size:- www.illustratingshadows.com/altDialLatitude.pdf Simon Simon Wheaton-Smith www.illustratingshadows.com Phoenix, Arizona, W112.1 N33.5 From: Steve Lelievre steve.lelievre.can...@gmail.com To: David Bell db...@thebells.net Cc: sundial@uni-koeln.de sundial@uni-koeln.de Sent: Sunday, June 1, 2014 3:46 PM Subject: Re: Request for information about a type of altitude dial Dave, That's the point I'm struggling to understand. I'm assuming a chain is used to suspend the dial in use, but wouldn't it adjust itself to bring the centre of gravity back under the point of suspension - effectively making it impossible to rotate the dial face? Steve On 01/06/2014 7:36 PM, David Bell wrote: I don't know the name, but I believe the moveable attachment point is where the hanging loop clamps to the dial plate. Moving that will rotate the dial and altitude scale relative to vertical. Dave Sent from my iPhone On Jun 1, 2014, at 3:13 PM, Steve Lelievre steve.lelievre.can...@gmail.com wrote: Hi folks, http://www.pinterest.com/pin/301178293801331061/ What type of dial is this; I realize it's a form of altitude dial, but is there a specific name for it? The accompanying note states that the dial can be adjusted for latitude by moving the attachment point. I don't understand which part of the mechanism does that. Can anyone explain it for me? Lastly, I'm appreciate references for articles or webpages that discuss these dials - history and mathematics. Thanks, Steve --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: altitude dial
That is a very impressive both mathematically, and as an original dial. -Bill On 1/25/2011 12:01 PM, Fabio Savian wrote: hi Frank, two years ago I designed a variant of the shepherd's dial so it became universal (for any latitude). The moving gnomon is curved (the curve is an astroid) and it may move up and down and also around the dial. The gnomon (the tail of the rooster, the crest and the beak are decorative) has to be placed in the point where the curve of the date (the Sun declination curve) crosses the curve of the latitude. The upper shadow of the tail shows the time. ciao Fabio Fabio Savian fabio.sav...@nonvedolora.it Paderno Dugnano, Milan, Italy 45 34' 10'' N 9 10' 9'' E GMT +1 (DST +2) --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
re altitude dial
Greetings, fellow dialists, Thanks, all, for the communications. I think I did not make it clear that I was thinking of a horizontal altitude dial, not a vertical one. It would look a bit like an analemmatic dial laid out on the ground. I understand how a shepherd's dial works and also how a vertical altitude dial with (say) six curves works. I have a nice picture of the altitude (and azimuth) dial once to be seen on a wall in the Royal Observatory at Greenwich. It has now, alas, been lost, together with the other five dials (planetary hours, equal hours, zodialcal signs, equation of time, hours from sunrise and sunset) made by a Polish dialist whose name I have sadly forgotten. The vertical altitude dial at Greenwich was very plain and simply had a fixed horizontal sun-hole gnomon with altitude curves (and vertical azimuth lines) beneath it. I envisage a horizontal dial with a single altitude curve and the vertical gnomon moving north -south to compensate for seasonal change. Is such a dial possible? Frank 55N 1W --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: re altitude dial
Frank, I made a horizontal altitude dial for the inside of a box. The date lines are parallel to 2 edges, one of the other 2 edges is the shadow casting object. The box has to be rotated to the sun so that the vertical edges parallel to the date lines point to the direction of sun (cast no shadow transversal to their direction) I calculated that with my software SONNE.EXE. I hope the attache image is not blocked. Otherwise send me a mail. Helmut Sonderegger www.helson.at - Original Message - From: Frank Evans frankev...@zooplankton.co.uk To: Sundial sund...@rrz.uni-koeln.de Sent: Wednesday, January 26, 2011 12:12 PM Subject: re altitude dial Greetings, fellow dialists, Thanks, all, for the communications. I think I did not make it clear that I was thinking of a horizontal altitude dial, not a vertical one. It would look a bit like an analemmatic dial laid out on the ground. I understand how a shepherd's dial works and also how a vertical altitude dial with (say) six curves works. I have a nice picture of the altitude (and azimuth) dial once to be seen on a wall in the Royal Observatory at Greenwich. It has now, alas, been lost, together with the other five dials (planetary hours, equal hours, zodialcal signs, equation of time, hours from sunrise and sunset) made by a Polish dialist whose name I have sadly forgotten. The vertical altitude dial at Greenwich was very plain and simply had a fixed horizontal sun-hole gnomon with altitude curves (and vertical azimuth lines) beneath it. I envisage a horizontal dial with a single altitude curve and the vertical gnomon moving north -south to compensate for seasonal change. Is such a dial possible? Frank 55N 1W --- https://lists.uni-koeln.de/mailman/listinfo/sundial attachment: Son1box.jpg--- https://lists.uni-koeln.de/mailman/listinfo/sundial
re. altitude dial
Dear Frank I cannot help you with the dial you construct but I can help with the lost Greenwich dials by a Polish dialist. His name was Tadeusz Przypkowski. Mr. Christopher Daniel wrote about the dials at Greenwich in his Maritime Monographs and Reports (No. 28) entitled Sundials on Walls. Mr. Daniel has kindly agreed for me to translate part of his monograph concerning the dials into polish and thus you can see them on my website. Copies of the original design grawings by Dr. Przypkowski follow the photographs. Here are the links: http://www.gnomonika.pl/news.php?id=29 http://www.gnomonika.pl/news.php?id=34 http://www.gnomonika.pl/news.php?id=42 I hope you will find there some help. -- Best regards Darek Oczki 52N 21E Warsaw, Poland GNOMONIKA.pl Sundials in Poland http://gnomonika.pl Date: Wed, 26 Jan 2011 11:12:59 + From: Frank Evans frankev...@zooplankton.co.uk To: Sundial sund...@rrz.uni-koeln.de Subject: re altitude dial Message-ID: 4d4001bb.1070...@zooplankton.co.uk Content-Type: text/plain; charset=ISO-8859-1; format=flowed Greetings, fellow dialists, Thanks, all, for the communications. I think I did not make it clear that I was thinking of a horizontal altitude dial, not a vertical one. It would look a bit like an analemmatic dial laid out on the ground. I understand how a shepherd's dial works and also how a vertical altitude dial with (say) six curves works. I have a nice picture of the altitude (and azimuth) dial once to be seen on a wall in the Royal Observatory at Greenwich. It has now, alas, been lost, together with the other five dials (planetary hours, equal hours, zodialcal signs, equation of time, hours from sunrise and sunset) made by a Polish dialist whose name I have sadly forgotten. The vertical altitude dial at Greenwich was very plain and simply had a fixed horizontal sun-hole gnomon with altitude curves (and vertical azimuth lines) beneath it. I envisage a horizontal dial with a single altitude curve and the vertical gnomon moving north -south to compensate for seasonal change. Is such a dial possible? Frank 55N 1W --- https://lists.uni-koeln.de/mailman/listinfo/sundial
altitude dial
Greetings, fellow dialists, I seek enlightenment. I understand that both analemmatic dials and the secondary dials of double horizontals are azimuth dials and both are based on the stereographic projection . The time curves on the double horizontal dial are multiple and dependent on the date while the single ellipse of an analemmatic dial is achieved through the movement of the gnomon north-south through the year. Almost every possible form of dial seems to have been devised already but I have not come across an altitude dial resembling an analemmatic dial in that the gnomon is moved with the seasons and the time curve is a single ellipse. The shepherd's dial is an altitude dial but with a gnomon fixed in place and more resembles the form of the double horizontal dial. Does an altitude dial with seasonally moving gnomon exist anywhere? Any help? Frank, 55N 1W --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Fwd: altitude dial
It seems to me you could consider the Capuchin dial variations, including the Navicula Venetiis, as altitude dials with a moving element. It's not a gnomon in the classic sense, but you do set the suspension point for the thread to the date. Jim James E. Morrisonjanus.astrol...@verizon.netAstrolabe web site at http://astrolabes.orgJan 25, 2011 11:08:02 AM, frankev...@zooplankton.co.uk wrote: Greetings, fellow dialists,I seek enlightenment. I understand that both analemmatic dials and the secondary dials of double horizontals are azimuth dials and both are based on the stereographic projection . The time curves on the double horizontal dial are multiple and dependent on the date while the single ellipse of an analemmatic dial is achieved through the movement of the gnomon north-south through the year.Almost every possible form of dial seems to have been devised already but I have not come across an altitude dial resembling an analemmatic dial in that the gnomon is moved with the seasons and the time curve is a single ellipse. The shepherd's dial is an altitude dial but with a gnomon fixed in place and more resembles the form of the double horizontal dial. Does an altitude dial with seasonally moving gnomon exist anywhere? Any help?Frank, 55N 1W---https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: altitude dial
hi Frank, two years ago I designed a variant of the shepherd's dial so it became universal (for any latitude). The moving gnomon is curved (the curve is an astroid) and it may move up and down and also around the dial. The gnomon (the tail of the rooster, the crest and the beak are decorative) has to be placed in the point where the curve of the date (the Sun declination curve) crosses the curve of the latitude. The upper shadow of the tail shows the time. ciao Fabio Fabio Savian fabio.sav...@nonvedolora.it Paderno Dugnano, Milan, Italy 45° 34' 10'' N 9° 10' 9'' E GMT +1 (DST +2) attachment: astronautsdial.jpg--- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: altitude dial
In message 4d3ef531.1090...@zooplankton.co.uk Frank Evans frankev...@zooplankton.co.uk wrote: Almost every possible form of dial seems to have been devised already but I have not come across an altitude dial resembling an analemmatic dial in that the gnomon is moved with the seasons and the time curve is a single ellipse. The shepherd's dial is an altitude dial but with a gnomon fixed in place and more resembles the form of the double horizontal dial. Does an altitude dial with seasonally moving gnomon exist anywhere? Any help? Frank, 55N 1W Hello, Frank No doubt other experts will have their own suggestions, but the one which immediately springs to mind, is a Capuchin type of sundial. Although it usually has a movable date-scale (similar to the method used on analemmatic dials), the 'gnomon' is normally a slit through which the light will shine, to correctly align altitude of the sun. In principle, however, it might be possible to arrange some type of movable gnomon with a fixed scale - but I would need to think about that some more, before I could offer any workable solution on this. Maybe you have definitely 'discovered' a new type of altitude dial. Sincerely, Martina Addiscott. P. S. - Have a good Rabbie Burns Night, over there in the U.K. ! -- --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: altitude dial
Dear Frank, You say: I have not come across an altitude dial resembling an analemmatic dial in that the gnomon is moved with the seasons and the time curve is a single ellipse. One interpretation of what you seek is to have a dial on a vertical wall where the gnomon is horizontal (and perpendicular to the wall) and moved to the right place according to the solar declination. I have put one such design in: http://www.cl.cam.ac.uk/users/fhk1/PEMB.pdf This is for the latitude of Cambridge and is for a wall which declines about 21 degrees to the east. I suspect that this is what you want. The key thing to note is that the axes of the ellipse are not vertical and horizontal unless the wall faces due south. All the best Frank Frank H King Cambridge UK --- https://lists.uni-koeln.de/mailman/listinfo/sundial
R: altitude dial
Frank, you can use Orologi Solari to design an analemmatic vertical dial like the one you describe. See the attached example. Greetings. Gian Casalegno http://digilander.libero.it/orologi.solari/ Messaggio originale Da: frankev...@zooplankton.co.uk Data: 25/01/2011 17.07 A: Sundialsund...@rrz.uni-koeln.de Ogg: altitude dial Greetings, fellow dialists, I seek enlightenment. I understand that both analemmatic dials and the secondary dials of double horizontals are azimuth dials and both are based on the stereographic projection . The time curves on the double horizontal dial are multiple and dependent on the date while the single ellipse of an analemmatic dial is achieved through the movement of the gnomon north-south through the year. Almost every possible form of dial seems to have been devised already but I have not come across an altitude dial resembling an analemmatic dial in that the gnomon is moved with the seasons and the time curve is a single ellipse. The shepherd's dial is an altitude dial but with a gnomon fixed in place and more resembles the form of the double horizontal dial. Does an altitude dial with seasonally moving gnomon exist anywhere? Any help? Frank, 55N 1W --- https://lists.uni-koeln.de/mailman/listinfo/sundial vertical analemmatic.pdf Description: Adobe PDF document --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: altitude dial
Hello Frank, all altitude sundials use only the Sun’s altitude. Since the altitude is measured on a vertical circle movable with the Sun, a sundial that bases its action on it has to be movable or to have some movable part around the vertical axis: in general the whole sundial can rotate around it. For this reason all the altitude sundials must have: 1 - many hourly curves and the gnomon that is moved on the day of observation. For example the shepherd s., the ring s., etc. 2 - many seasonal curves and the gnomon mobile. When the shadow of its extreme meets the line of the day, the position of his foot gives the hour. 3 - hourly and seasonal curves, these often straight line segments, and a fixed gnomon. For ex. the famous Portici Ham sundial. So you cannot have an altitude sundial with a single curve on which the hours are placed (that is, hourly lines reduced to points) as in analemmatic. Analemmatic are never altitude sundials, even if they are built on a vertical wall. A sundial that perhaps is close to what you have described is, for example, a shepherd s. with the cylinder surface developed on a plane, like the one in the picture. Best Gianni Ferrari attachment: a.jpg--- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: R: altitude dial
Dear Gian Casalengo, Thank you for your interesting example... ...you can use Orologi Solari to design an analemmatic vertical dial like the one you describe. I am glad we get the same answer! Gianni Ferrari is quite right... ... Analemmatic are never altitude sundials, even if they are built on a vertical wall. Nevertheless, I think the sundial that Frank Evans wants IS an Analemmatic Dial on a Vertical Wall. He wants an elliptical hour ring and so on. Perhaps he will tell us all soon! Frank King --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Horizontal Altitude Dial (DeltaCad)
I am sending again my e-mail because it does not appear in the archive http://www.mail-archive.com/sundial@uni-koeln.de/maillist.html. Perhaps attachments are not allowed, therefore I include the .bas file inside the message (it is possible to receive some of the lines splitted). Here is my original e-mail: --- Dear dialists! Greetings from the unusually warm Bulgaria, where we enjoj the beautiful sunny winter (it is like spring)! I am writing to you to announce a new member of the Box Sundial Family of DeltaCad macros. This is a well known type of Sundial - Horizontal Altitude Dial. It uses the altitude (height) of the Sun to indicate the time. There is a possibility to chose to include or exclude the corrections for the Equation Of Time and for the Longitude (with respect to the Central Meridian of the Time Zone). Excluding both gives the Local Solar Time. Including both gives the Civil and the Daylight Savings Time. To find the time simply put the box on a horizontal place and rotate it until the direction of the central arrow is towards the Sun. Use the shadow of one of the edges on one of the morning or the afternoon drawings. Unfortunately such type of sundial is not useful close to the local noon and also at places with bigger latitude (i.e. closer to the poles) because in such cases the height (altitude) of the sun changes very slow. The Box Dial can be folded to a small flat rectange and you can carry it everywhere with you. After printing landscape on A4 paper, you can make a bigger A3 copy, which allows easier reading. The size of the box is still small enough. Recently two of my DeltaCad macros for drawing Box Dials without gnomon were added to the DeltaCad library on the NASS web page http://www.sundials.org/links/local/deltacad/ Two days ago the new macro was also put there - Thank you, Bob! Some more instructions: First of all rename the attachments from sdboxh.ba to sdboxh.bas and sdboxh.zi to sdboxh.zip. I changed deliberately the extensions of the files because some servers do not allow .bas or .zip attachments. If neither of the files is available, simply download the .zip file http://www.sundials.org/links/local/deltacad/zips/SDBoxH.zip There is a fully functioning Demo version of DeltaCad at www.deltacad.com. Use the menu Options - Macro - Run... or the separate Macro button - Edit Macro List, add the file, and Run Macro. In the dialog box use DECIMAL DEGREES. Negative values indicate South for latitude and West for longitude and Central Meridian. Zeros for EOT and longitude corrections will give the local time. The initial opening screen contains data for my place. If you want the parameters for your place and your preferences to appear as default, use any text editor to change the lines around 139-145 and save the file as text (ASCII) file. You can send your comments to my e-mail address [EMAIL PROTECTED] (or to the sundial list). I hope you will enjoy my new construction! Best wishes and more sunny days! Valentin Hristov P.S. Some years ago I made another sundial which uses the altitude (heght) of the sun, but it is a PostScript file. You can download QUADRANT.PS from my old web page in Zimbabwe (from 2002, but still alive...): www.uz.ac.zw/science/maths/personal/hristov/index.htm. File SDBoxH.bas ' '* SDBOXH.bas is a DeltaCad macro for producing a * '* Pocket Folding Box Horizontal Altitude Sundial * '* with Longitude Correction and EOT Correction.* '* Created by Valentin Hristov ([EMAIL PROTECTED]). * '* One of the edges is used as a gnomon.* '* I was inspired by Mac Oglesby to use the * '* North American Sundial Society DeltaCad programs * '* as tutorials (http://sundials.org) * '* and made with DeltaCad (www.deltacad.com)* '* different types of sundials. * ' '* To assemble the sundial, cut along the solid lines, make mountain folds '* along the lines with long dashes, and valley folds along the lines '* with short dashes. '* To find the time simply put the box on a horizontal place and rotate '* it until the direction of the central arrow is towards the Sun. Use '* the morning or the afternoon drawing. '* Unfortunately such type of sundial is not useful close to the local '* noon and also at places with bigger latitude (i.e. closer to the '* poles) because the height (altitude) of the sun changes then very '* slow. '* You can see the picture of another type of sundial generated by one '* of my DeltaCad macros at '* www.flickr.com/photos/Valentin_Hristov/261303801/ '* Click on the button All sizes to see a bigger photo with details. '* I am very grateful to my friends Daniela (www.danyo.net) and '* Todor (www.todor.org) who converted my drawing into a real art piece
