Re: A 14th century sundial question from France.
Hi Bill (and other dialling colleagues), The data that you show looks very similar to the Venerable Bede's shadow length tables (though the values are slightly different). This gives the length of a person's shadow on the assumption that their height is equal to six of their own feet (tall people generally have big feet!). But the hours are probably not the modern equal ones. This topic will be discussed in some detail in the forthcoming June issue of the BSS Bulletin. A reason for the inaccuracies will be proposed, together with a rather more accurate version of the same table, to be found in an Anglo-Saxon manuscript. Regards, John - Dr J Davis Flowton Dials --- On Wed, 9/3/11, Bill Gottesman billgottes...@comcast.net wrote: From: Bill Gottesman billgottes...@comcast.net Subject: A 14th century sundial question from France. To: Sundial Mailing List sund...@rrz.uni-koeln.de Date: Wednesday, 9 March, 2011, 1:06 Richard Kremer, the Dartmouth physics professor who brought the ~1773 Dartmouth Sundial to display at the NASS convention this past summer, asked me the following question. I have done a bit of modelling on it, and have not been able to supply a satisfactory answer. Is anyone interested in offering any insight? My hunch is that the astronomer who wrote this guessed at many of these numbers, and that they will be estimates at best for whatever model they are based on. I have tried to fit them to antique, equal, and Babylonian hours, without success. In 1320, the equinoxes occured around March and Sept 14 by the Julian Calendar, as best I can tell, and that doesn't seem to help any. -Bill --- I've got a sundial geometry question for you and presume that either you, or someone you know, can sort it out for me. A colleague has found a table of shadow lengths in a medieval astronomical table (about 1320 in Paris). The table gives six sets of lengths, for 2-month intervals, and clearly refers to some kind of gnomon that is casting the shadows. The manuscript containing this table of shadow lengths appears in a manuscript written by Paris around 1320 by John of Murs, a leading Parisian astronomer. I don't know whether Murs himself composed the table or whether he found it in some other source. The question is, what kind of dial is this. A simple vertical gnomon on a horizontal dial does not fit the data, which I give below. Dec-Jan hour 1 27 feet hour 2 17 feet hour 3 13 feet hour 4 10 feet hour 5 8 feet hour 6 [i.e., noon] 7 feet Nov-Feb 1 26 2 16 3 12 4 9 5 7 6 6 Oct-Mar 1 25 2 15 3 11 4 8 5 6 6 5 Sept-Apr 1 24 2 14 3 10 4 7 5 5 6 4 Aug-May 1 23 2 13 3 9 4 6 5 4 6 3 Jul-Jun 1 22 2 12 3 8 4 5 5 3 6 2 Note that in each set, the shadow lengths decrease in identical intervals (-10, -4, -3, -2, -1). This might suggest that the table is generated by some rule of thumb and not by exact geometrical calculation, for by first principles I would not expect these same decreasing intervals to be found in all six sets! I started playing with the noon shadow lengths at the solstices, looking for a gnomon arrangement that yields equal lengths of the gnomon for shadow lengths of 7 (Dec) and 2 (Jun) units. If you assume the dial is horizontal and you tilt the gnomon toward the north by 55 degs, my math shows that you get a gnomon length of 2.16 units. I assume that Paris latitude is 49 degs and the obliquity of the ecliptic is 23.5 degs (commonly used in middle ages). I'm too lazy to figure out the shadow lengths for the other hours of the day with a slanted gnomon, and presume that you have software that can easily do that. Would you be willing to play around a bit with the above lengths and see if you can determine what gnomon arrangement might yield these data? Perhaps the dial is vertical rather than horizontal? In any case, the data are symmetrical, so the gnomon must be in the plane of the meridian. Knowing that you like puzzles, I thought I'd pass this one on to you. If you don't have time for it, don't worry. This is not the most important problem currently facing the history of astronomy! Best, Rich --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
RE: A 14th century sundial question from France.
I had exactly the same thought as John-that this was a table of shadow lengths in the form that Bede gives in the 7th century. Sara 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://www.fas.harvard.edu/~hsdept/chsi.html From: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] On Behalf Of JOHN DAVIS Sent: Wednesday, March 09, 2011 5:13 AM To: Sundial Mailing List; Bill Gottesman Subject: Re: A 14th century sundial question from France. Hi Bill (and other dialling colleagues), The data that you show looks very similar to the Venerable Bede's shadow length tables (though the values are slightly different). This gives the length of a person's shadow on the assumption that their height is equal to six of their own feet (tall people generally have big feet!). But the hours are probably not the modern equal ones. This topic will be discussed in some detail in the forthcoming June issue of the BSS Bulletin. A reason for the inaccuracies will be proposed, together with a rather more accurate version of the same table, to be found in an Anglo-Saxon manuscript. Regards, John - Dr J Davis Flowton Dials --- On Wed, 9/3/11, Bill Gottesman billgottes...@comcast.netmailto:billgottes...@comcast.net wrote: From: Bill Gottesman billgottes...@comcast.netmailto:billgottes...@comcast.net Subject: A 14th century sundial question from France. To: Sundial Mailing List sund...@rrz.uni-koeln.demailto:sund...@rrz.uni-koeln.de Date: Wednesday, 9 March, 2011, 1:06 Richard Kremer, the Dartmouth physics professor who brought the ~1773 Dartmouth Sundial to display at the NASS convention this past summer, asked me the following question. I have done a bit of modelling on it, and have not been able to supply a satisfactory answer. Is anyone interested in offering any insight? My hunch is that the astronomer who wrote this guessed at many of these numbers, and that they will be estimates at best for whatever model they are based on. I have tried to fit them to antique, equal, and Babylonian hours, without success. In 1320, the equinoxes occured around March and Sept 14 by the Julian Calendar, as best I can tell, and that doesn't seem to help any. -Bill --- I've got a sundial geometry question for you and presume that either you, or someone you know, can sort it out for me. A colleague has found a table of shadow lengths in a medieval astronomical table (about 1320 in Paris). The table gives six sets of lengths, for 2-month intervals, and clearly refers to some kind of gnomon that is casting the shadows. The manuscript containing this table of shadow lengths appears in a manuscript written by Paris around 1320 by John of Murs, a leading Parisian astronomer. I don't know whether Murs himself composed the table or whether he found it in some other source. The question is, what kind of dial is this. A simple vertical gnomon on a horizontal dial does not fit the data, which I give below. Dec-Jan hour 1 27 feet hour 2 17 feet hour 3 13 feet hour 4 10 feet hour 5 8 feet hour 6 [i.e., noon] 7 feet Nov-Feb 1 26 2 16 3 12 4 9 5 7 6 6 Oct-Mar 1 25 2 15 3 11 4 8 5 6 6 5 Sept-Apr 1 24 2 14 3 10 4 7 5 5 6 4 Aug-May 1 23 2 13 3 9 4 6 5 4 6 3 Jul-Jun 1 22 2 12 3 8 4 5 5 3 6 2 Note that in each set, the shadow lengths decrease in identical intervals (-10, -4, -3, -2, -1). This might suggest that the table is generated by some rule of thumb and not by exact geometrical calculation, for by first principles I would not expect these same decreasing intervals to be found in all six sets! I started playing with the noon shadow lengths at the solstices, looking for a gnomon arrangement that yields equal lengths of the gnomon for shadow lengths of 7 (Dec) and 2 (Jun) units. If you assume the dial is horizontal and you tilt the gnomon toward the north by 55 degs, my math shows that you get a gnomon length of 2.16 units. I assume that Paris latitude is 49 degs and the obliquity of the ecliptic is 23.5 degs (commonly used in middle ages). I'm too lazy to figure out the shadow lengths for the other hours of the day with a slanted gnomon, and presume that you have software that can easily do that. Would you be willing to play around a bit with the above lengths and see if you can determine what gnomon arrangement might yield these data? Perhaps the dial is vertical rather than horizontal? In any case, the data are symmetrical, so the gnomon must be in the plane of the meridian. Knowing that you like puzzles, I thought I'd pass this one on to you. If you don't have time for it, don't worry. This is not the most important problem currently
Re: A 14th century sundial question from France.
Dear Friends Don't forget the beautiful Missal of St Leofric 10-11th Century for an elegant but simple shadow length table see http://image.ox.ac.uk/show?collection=bodleianmanuscript=msbodl579 and find folio 58 recto Does anyone know if Bede's Table is available in manuscript image form anywhere on the web (plus a translation...!)? Best regards Kevin Karney Freedom Cottage, Llandogo, Monmouth NP25 4TP, Wales, UK 51° 44' N 2° 41' W Zone 0 + 44 1594 530 595 On 9 Mar 2011, at 15:03, Schechner, Sara wrote: I had exactly the same thought as John—that this was a table of shadow lengths in the form that Bede gives in the 7th century. Sara 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://www.fas.harvard.edu/~hsdept/chsi.html From: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] On Behalf Of JOHN DAVIS Sent: Wednesday, March 09, 2011 5:13 AM To: Sundial Mailing List; Bill Gottesman Subject: Re: A 14th century sundial question from France. Hi Bill (and other dialling colleagues), The data that you show looks very similar to the Venerable Bede's shadow length tables (though the values are slightly different). This gives the length of a person's shadow on the assumption that their height is equal to six of their own feet (tall people generally have big feet!). But the hours are probably not the modern equal ones. This topic will be discussed in some detail in the forthcoming June issue of the BSS Bulletin. A reason for the inaccuracies will be proposed, together with a rather more accurate version of the same table, to be found in an Anglo-Saxon manuscript. Regards, John - Dr J Davis Flowton Dials --- On Wed, 9/3/11, Bill Gottesman billgottes...@comcast.net wrote: From: Bill Gottesman billgottes...@comcast.net Subject: A 14th century sundial question from France. To: Sundial Mailing List sund...@rrz.uni-koeln.de Date: Wednesday, 9 March, 2011, 1:06 Richard Kremer, the Dartmouth physics professor who brought the ~1773 Dartmouth Sundial to display at the NASS convention this past summer, asked me the following question. I have done a bit of modelling on it, and have not been able to supply a satisfactory answer. Is anyone interested in offering any insight? My hunch is that the astronomer who wrote this guessed at many of these numbers, and that they will be estimates at best for whatever model they are based on. I have tried to fit them to antique, equal, and Babylonian hours, without success. In 1320, the equinoxes occured around March and Sept 14 by the Julian Calendar, as best I can tell, and that doesn't seem to help any. -Bill --- I've got a sundial geometry question for you and presume that either you, or someone you know, can sort it out for me. A colleague has found a table of shadow lengths in a medieval astronomical table (about 1320 in Paris). The table gives six sets of lengths, for 2-month intervals, and clearly refers to some kind of gnomon that is casting the shadows. The manuscript containing this table of shadow lengths appears in a manuscript written by Paris around 1320 by John of Murs, a leading Parisian astronomer. I don't know whether Murs himself composed the table or whether he found it in some other source. The question is, what kind of dial is this. A simple vertical gnomon on a horizontal dial does not fit the data, which I give below. Dec-Jan hour 1 27 feet hour 2 17 feet hour 3 13 feet hour 4 10 feet hour 5 8 feet hour 6 [i.e., noon] 7 feet Nov-Feb 1 26 2 16 3 12 4 9 5 7 6 6 Oct-Mar 1 25 2 15 3 11 4 8 5 6 6 5 Sept-Apr 1 24 2 14 3 10 4 7 5 5 6 4 Aug-May 1 23 2 13 3 9 4 6 5 4 6 3 Jul-Jun 1 22 2 12 3 8 4 5 5 3 6 2 Note that in each set, the shadow lengths decrease in identical intervals (-10, -4, -3, -2, -1). This might suggest that the table is generated by some rule of thumb and not by exact geometrical calculation, for by first principles I would not expect these same decreasing intervals to be found in all six sets! I started playing with the noon shadow lengths at the solstices, looking for a gnomon arrangement that yields equal lengths of the gnomon for shadow lengths of 7 (Dec) and 2 (Jun) units. If you assume the dial is horizontal and you tilt the gnomon toward the north by 55 degs, my math shows that you get a gnomon length of 2.16 units. I assume that Paris latitude is 49 degs and the obliquity of the ecliptic is 23.5 degs (commonly used in middle ages). I'm too lazy to figure out the shadow lengths for the
Re: Leap Years
Dear Brent, You ask a fascinating set of questions. Has the leap year problem been solved with solar calendars? At one level, the problem is intractable. You get defeated by the calendar bequeathed to us by Pope Gregory XIII... The problem is that the Gregorian calendar is hardly an improvement on the Julian calendar. Indeed, right now, we are barely half way through a near 200-year run of pure Julian calendar. The last time a leap year was omitted from the regular 4-year cycle was in 1900 and the next time will be 2100. The Julian drift which prompted calendar reform in 1582 is very much still a problem for those of us who build calendars into our sundials. OK, end of ranting about Pope Gregory (who actually had many merits but calendar reform wasn't one of them). All that said, you can have a perfectly good solar calendar which will work just fine for 36 years before Julian drift defeats you. If it is a painted sundial, you could leave some documentation as to how it should be repainted every 36 years and set up for the next 36 years. Let's start afresh with a minimalist sundial which is set out on horizontal ground and consists of a nodus and a noon line and nothing else. Proceed as follows, starting at local sun noon on 1 March 2011. This is a crucial date. Pity you missed it! 1. From, say, four minutes *before* local sun noon until spot on sun noon sketch the path traced by the shadow of the nodus as it approaches the noon line on 1 March 2011. 2. Repeat on 2 March 2011. The declination is slightly higher so the path will be very slightly further south than the path was the previous day. 3. Keep going until the summer solstice. The succession of lines will now stop heading south and begin to head north... 4. Still keep going but, to avoid confusion in the sketch, trace the path from spot on sun noon until four minutes *after* noon. This way, as the sun's declination decreases and your sketch folds back on itself, you won't have little lines messing up the ones you already drew. 5. Keep going until the winter solstice. 6. Still keep going but now go back to sketching lines *before* noon. The lines will start heading south again. 7. Keep going until 12 noon on 29 February next year. You will have drawn EXACTLY 365 little lines. [Note that 29 February is 365 days AFTER 1 March the previous year, not 366 days.] 8. In the vicinity of 29 February, the lines you drew will be approximately equally spaced except that the space between the line for 29 February 2012 and the line for 1 March 2011 will be just under a quarter of the space between the other adjacent lines in the vicinity. 9. Still with me? It takes just under 365 and a quarter days for the declination to get back to what it was on 1 March the previous year. Hence the anomalous gap. 10. Now, DON'T STOP. Just keep going for 1 March 2012 and so on. You will find that the line for 1 March 2012 is about three-quarters of the way from the 1 March 2011 line to the 2 March 2011 line. You really are closer to the old 2 March line than the old 1 March line. 11. I am a hard task-master. I want you to keep going for 36 years. Well you did ask what to do after all :-) 12. You will, of course, have 36 lines for 1 March which form a patch. You will have 36 lines for 2 March which form another patch and so on BUT you have only 9 lines for 29 February and they form a patch which is just under a quarter of the width of neighbouring patches. 13. Your solar calendar is almost complete. You label these patches rather than the individual lines and it all works. When the solar declination is increasing (Winter Solstice to Summer Solstice) the shadow will cross the 1 March patch only on 1 March. It will cross the 29 February patch only on 29 February. In years that are not leap years it skips that patch. 14. For maximum benefit, it really is best to start on 1 March the year before a leap year. That's why I said you should start on 1 March 2011. Does it work? Has it been done? Yes. Yes. Been there, done that, got the T-shirt. Take a look at: http://www.cl.cam.ac.uk/users/fhk1/PSQ.jpg This photograph was taken by David Isaacs. You can see the little patches which are alternating red-brown and grey. You can see the patch for 29 February is just under one-quarter the width of its two neighbours, 28 February and 1 March. This is on a (nearly) vertical wall instead of on the ground but the idea is the same. To make it more interesting, instead of having patches either side of a vertical noon line I have them making up an analemma so you get the extra bonus of knowing when local mean noon. Actually,
Re: Leap Year - amendment
Dear Brent, Slight goof. In step 7 I meant to say: 7. Keep going until 12 noon on 29 February next year. You will have drawn EXACTLY 366 little lines. [Note that 29 February is 365 days AFTER 1 March the previous year, not 366 days.] You have 366 lines and 365 normal gaps plus one thin gap to close the loop. I always get muddled when I try to explain that :-( All the best Frank. --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Leap Year
Dear Andrew, Thank you for your two messages, sent off-list but my response may be of trifling interest to others... It is true that 128 tropical years is very close to 46751 days but when it comes to a real solar calendar (one you can look at and say Oh, I see that today is 9 March) I regard this fact as a red herring. It is also very dubious long term. The simple question: How many days are there in a tropical year? has no useful answer beyond about three decimal places. The awkward fact is that neither the length of the year nor the length of the day is a constant. The length of the day changes in an especially horribly unpredictable manner which is why leap seconds are unpredictable. I don't see where 36 fits in... This is a purely practical matter. If you sketch in my lines for, say, 12 noon on 1 March and 12 noon on 2 March each year for a number of years you will find that you are scribbling in two patches. The patches gradually fill in (unless you have a VERY sharp pencil) and expand. After 36 years you find that adjacent patches collide. They run into each other. In the region of overlap, you cannot tell whether the shadow refers to 1 March or 2 March. Your instrument is at the end of its design life and you have to redraw it for the next 36 years. Life becomes impossibly difficult around 2100 because of the omitted leap year then and the best thing you can do is redraw your instrument for the 36 years from 1 March 2103. My ghost will be lurking around to check that you get it right. I also see that 33 tropical years is just 11 and a bit minutes short of a whole number (12053) of days. Is this connected? Yes. Now you are really getting somewhere and I am starting to salivate at the prospect of writing a juicy reply :-) I seem to remember there are or were various calendar proposals based on 33 year cycles... Yes. Such a calendar was devised by Omar Khayyam (and others) in 1079. This was and still would be an absolutely super calendar, MUCH better than the horrid muddle we have to live with! A 33-year cycle which includes 8 leap years would be perfect if the length of year was 365 plus 8/33 days and it jolly nearly is. You still get very long term drift and you cannot win against the unpredictability of the length of the day but, with such a calendar, my patches start colliding after more like 500 years rather than a miserable 36. Pope Gregory missed a trick. By 1582 the 33-year calendar had been known about for over 500 years. Moreover, Pope Gregory's Commission included Na'amat Allah an eastern patriarch who would certainly have known about the 33-year calendar. If I could do only one thing as Dictator Of The World it would be to introduce Omar Khayyam's calendar. Vote for me! All the best Frank --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Moscow sundial?
All, I am trying to find a YouTube video that was linked to from this list several years ago. It shows a large analemmatic sundial located in a public park in Moscow (I think). Various passersby tried to figure out how it worked, where to stand, etc., and it was pretty funny. This could not have been before 2005, the year YouTube started. Anyone have the link? Roger --- https://lists.uni-koeln.de/mailman/listinfo/sundial
standard meridian list
I'm trying to find a list of cities and the standard meridian they set their clock to. Example Brisbane - 150 deg east San Fransisco - 120 deg west Paris - 15 deg east London - 0 deg -- Cheers Donald 0423 102 090 This e-mail is privileged and confidential. If you are not the intended recipient please delete the message and notify the sender. Un-authorized use of this email is subject to penalty of law. So there! --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: standard meridian list
Görlitz - 15 deg east Donald Christensen dchristensen...@gmail.com schrieb: I'm trying to find a list of cities and the standard meridian they set their clock to. Example Brisbane - 150 deg east San Fransisco - 120 deg west Paris - 15 deg east London - 0 deg -- Cheers Donald 0423 102 090 This e-mail is privileged and confidential. If you are not the intended recipient please delete the message and notify the sender. Un-authorized use of this email is subject to penalty of law. So there! --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: A 14th century sundial question from France.
The data that you show looks very similar to the Venerable Bede's shadow length tables (though the values are slightly different). This gives the length of a person's shadow on the assumption that their height is equal to six of their own feet (tall people generally have big feet!). But the hours are probably not the modern equal ones. -- Dear friends, can I suggest you the reading of an exellent and almost complete article about shadows schemes written by Karlheinz Schaldach? The article is found in Gnomonica Italiana n. 16, november 2008. In this article Schaldach analize more than 40 medieval shadows schemes putting them into distinct models classified by the numerical sequence. As John wrote this is a simple shadow sheme common in medieval time up to the 16th century, usually called Horologium or horologium viatorum. The numerical sequence given by Bill is not the sequence written by pseudo-Beda (I say pseudo-Beda just because is not sure at all that the sheme that we usually say is from Beda is really from Beda. That scheme is usual in the Fleury manuscripts). The sequence that we call from Beda has been categorized by Schaldach in a Saint Gallen model (because is very common in the manuscripts present in that abbey and commonly of Irish origin), variant C1. In the scheme written by Bill we can recognise a rare scheme: the model of Flavigny, and Karlheinz Schaldach knows only one example (Leiden, UB Scaliger 28, fol. 2v) dated to the 9th cent. The model of Flavigny is really very similar to the famous, and almost unique, shadow scheme of Palladius, but it changes the Dec-Jan and Nov-Feb colums - Palladius: Dec-Jan hour 1 29 feet hour 2 19 feet hour 3 15 feet hour 4 12 feet hour 5 10 feet hour 6 9 feet Nov-Feb 1 27 2 17 3 13 4 10 5 8 6 7 Flavigny: 27 feet 17 feet 14 feet 10 feet 8 feet 7 feet Nov-Feb 1 26 2 16 3 13 4 9 5 7 6 6 -- As we can see the sequence is very similar to the one shoed by Bill, but one difference: the shadow lengthf the 3-9th hour is major of one unit. The sequence of the 3d and 9th hour in the Flavigny scheme is:14, 13, 12, 11, 10, 9 - while in the Bill sheme is: 13, 12, 11, 10, 9, 8. So the sequence of the intervals for Flavigny is (-10, -3 -4 -2, -1) while for the Bill text is (-10, -4, -3, -2, -1). This sounds as the scheme from Bill is the more correct Flavigny model, but to prove this we should find another ms with correct sequence daded bak almost to the 9th century. Bytheway the Leiden ms is earlier than the Bill written scheme, so we can surely say that this last scheme is not from John of Murs, but older. Thanks Mario Arnaldi --- https://lists.uni-koeln.de/mailman/listinfo/sundial
AW: Moscow sundial?
Dear Roger, it might well be you are looking for the very beautiful sundial-YouTube-film which you can easily find within this link: http://www.ta-dip.de/sonnenuhren/sonnenuhren-von-freunden/r-u-s-s-l-a-n- d/aleksandr-w-boldyrev.html Have a look! The beautiful young Russian women enjoy this sundial, made by Aleksandr W Boldyrev as well as the pigeons and the little children and some men! Enjoy! Best regards! Reinhold Kriegler * ** *** * ** *** Reinhold R. Kriegler Lat. 53° 6' 52,6 Nord; Long. 8° 53' 52,3 Ost; 48 m ü. N.N. GMT +1 (DST +2) www.ta-dip.de http://de.youtube.com/watch?v=XyCoJHwzzjUfmt=18 http://www.ta-dip.de/dies-und-das/r-e-i-n-h-o-l-d.html -Ursprüngliche Nachricht- Von: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] Im Auftrag von Roger W. Sinnott Gesendet: Mittwoch, 9. März 2011 22:44 An: 'Sundial List' Betreff: Moscow sundial? All, I am trying to find a YouTube video that was linked to from this list several years ago. It shows a large analemmatic sundial located in a public park in Moscow (I think). Various passersby tried to figure out how it worked, where to stand, etc., and it was pretty funny. This could not have been before 2005, the year YouTube started. Anyone have the link? Roger --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
RE: Moscow sundial?
Hi Reinhold, Yes, thats it!! Many thanks. When it was first posted, I remember a comment by someone on this list: Most of the people stood on the label of the month, rather than on the point on the centerline to which the label referred. (Im not sure what point the pigeons went to.) Roger Direct link: http://www.youtube.com/user/AleksandrBoldyrev?gl=RU http://www.youtube.com/user/AleksandrBoldyrev?gl=RUhl=ru hl=ru From: Reinhold Kriegler [mailto:reinhold.krieg...@gmx.de] Sent: Wednesday, March 09, 2011 5:47 PM To: 'Roger W. Sinnott'; 'Sundial List' Subject: AW: Moscow sundial? Dear Roger, it might well be you are looking for the very beautiful sundial-YouTube-film which you can easily find within this link: http://www.ta-dip.de/sonnenuhren/sonnenuhren-von-freunden/r-u-s-s-l-a-n-d/al eksandr-w-boldyrev.html Have a look! The beautiful young Russian women enjoy this sundial, made by Aleksandr W Boldyrev as well as the pigeons and the little children and some men! Enjoy! Best regards! Reinhold Kriegler * ** *** * ** *** Reinhold R. Kriegler Lat. 53° 6' 52,6 Nord; Long. 8° 53' 52,3 Ost; 48 m ü. N.N. GMT +1 (DST +2) www.ta-dip.de http://de.youtube.com/watch?v=XyCoJHwzzjU http://de.youtube.com/watch?v=XyCoJHwzzjUfmt=18 fmt=18 http://www.ta-dip.de/dies-und-das/r-e-i-n-h-o-l-d.html -Ursprüngliche Nachricht- Von: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] Im Auftrag von Roger W. Sinnott Gesendet: Mittwoch, 9. März 2011 22:44 An: 'Sundial List' Betreff: Moscow sundial? All, I am trying to find a YouTube video that was linked to from this list several years ago. It shows a large analemmatic sundial located in a public park in Moscow (I think). Various passersby tried to figure out how it worked, where to stand, etc., and it was pretty funny. This could not have been before 2005, the year YouTube started. Anyone have the link? Roger --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
RE: Moscow sundial?
Loved the human dial video! I sent the video link to a client in Michigan who is ordering a human sundial design. She thought it was fantastic. It will be a great selling tool for potential clients! Thx so much! John p.s. BTW, We are featuring Alek Boldyrevs stained glass sundial as our Sundial of the Month at www.stainedglasssundials.com. Its a rather unique design that places the sundial in a tall handsome wood frame on a upright stand in a park near Moscow. From: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] On Behalf Of Reinhold Kriegler Sent: Wednesday, March 09, 2011 3:47 PM To: 'Roger W. Sinnott'; 'Sundial List' Subject: AW: Moscow sundial? Dear Roger, it might well be you are looking for the very beautiful sundial-YouTube-film which you can easily find within this link: http://www.ta-dip.de/sonnenuhren/sonnenuhren-von-freunden/r-u-s-s-l-a-n-d/al eksandr-w-boldyrev.html Have a look! The beautiful young Russian women enjoy this sundial, made by Aleksandr W Boldyrev as well as the pigeons and the little children and some men! Enjoy! Best regards! Reinhold Kriegler * ** *** * ** *** Reinhold R. Kriegler Lat. 53° 6' 52,6 Nord; Long. 8° 53' 52,3 Ost; 48 m ü. N.N. GMT +1 (DST +2) www.ta-dip.de http://de.youtube.com/watch?v=XyCoJHwzzjUfmt=18 http://www.ta-dip.de/dies-und-das/r-e-i-n-h-o-l-d.html -Ursprüngliche Nachricht- Von: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] Im Auftrag von Roger W. Sinnott Gesendet: Mittwoch, 9. März 2011 22:44 An: 'Sundial List' Betreff: Moscow sundial? All, I am trying to find a YouTube video that was linked to from this list several years ago. It shows a large analemmatic sundial located in a public park in Moscow (I think). Various passersby tried to figure out how it worked, where to stand, etc., and it was pretty funny. This could not have been before 2005, the year YouTube started. Anyone have the link? Roger --- https://lists.uni-koeln.de/mailman/listinfo/sundial --- https://lists.uni-koeln.de/mailman/listinfo/sundial
Re: Leap Years
Hi Frank; Thank you for that detailed response. While I am trying to digest all of that I have a new question. Do the ancient solar calendars like the Incas still work? Do their rocks still show where the solstices will occur now? Your explanation below seems to indicate that their calendars would get progressively worse in predicting the day of solstices. On a side thought, the problem seems to be that we are using the time for the earth to spin around (a day) to measure the time it takes the earth to go around the sun (a year). These are two different events and it doesn't make sense to use one to measure the other. A day is a day and a year is a year, we shouldn't mix the two as it makes for a very messy situation. Forget the Popes calendar, can't I make a solar calendar that depicts a true solar year? It would mark the two solstices, the time between those two points is half a solar year. Half way in between those are the two equinoxes which would mark 1/4 of a year and we could keep halving the differences to get 1/8, 1/16, 1/32, 1/64 of a year etc... So we don't try to define a year in earth days but just split up a true year into equal parts. And this solar calendar would need no leap year and would always be correct. Maybe :) On 3/9/2011 9:27 AM, Frank King wrote: Dear Brent, You ask a fascinating set of questions. Has the leap year problem been solved with solar calendars? At one level, the problem is intractable. You get defeated by the calendar bequeathed to us by Pope Gregory XIII... The problem is that the Gregorian calendar is hardly an improvement on the Julian calendar. Indeed, right now, we are barely half way through a near 200-year run of pure Julian calendar. The last time a leap year was omitted from the regular 4-year cycle was in 1900 and the next time will be 2100. The Julian drift which prompted calendar reform in 1582 is very much still a problem for those of us who build calendars into our sundials. OK, end of ranting about Pope Gregory (who actually had many merits but calendar reform wasn't one of them). All that said, you can have a perfectly good solar calendar which will work just fine for 36 years before Julian drift defeats you. If it is a painted sundial, you could leave some documentation as to how it should be repainted every 36 years and set up for the next 36 years. Let's start afresh with a minimalist sundial which is set out on horizontal ground and consists of a nodus and a noon line and nothing else. Proceed as follows, starting at local sun noon on 1 March 2011. This is a crucial date. Pity you missed it! 1. From, say, four minutes *before* local sun noon until spot on sun noon sketch the path traced by the shadow of the nodus as it approaches the noon line on 1 March 2011. 2. Repeat on 2 March 2011. The declination is slightly higher so the path will be very slightly further south than the path was the previous day. 3. Keep going until the summer solstice. The succession of lines will now stop heading south and begin to head north... 4. Still keep going but, to avoid confusion in the sketch, trace the path from spot on sun noon until four minutes *after* noon. This way, as the sun's declination decreases and your sketch folds back on itself, you won't have little lines messing up the ones you already drew. 5. Keep going until the winter solstice. 6. Still keep going but now go back to sketching lines *before* noon. The lines will start heading south again. 7. Keep going until 12 noon on 29 February next year. You will have drawn EXACTLY 365 little lines. [Note that 29 February is 365 days AFTER 1 March the previous year, not 366 days.] 8. In the vicinity of 29 February, the lines you drew will be approximately equally spaced except that the space between the line for 29 February 2012 and the line for 1 March 2011 will be just under a quarter of the space between the other adjacent lines in the vicinity. 9. Still with me? It takes just under 365 and a quarter days for the declination to get back to what it was on 1 March the previous year. Hence the anomalous gap. 10. Now, DON'T STOP. Just keep going for 1 March 2012 and so on. You will find that the line for 1 March 2012 is about three-quarters of the way from the 1 March 2011 line to the 2 March 2011 line. You really are closer to the old 2 March line than the old 1 March line. 11. I am a hard task-master. I want you to keep going for 36 years. Well you did ask what to do after all :-) 12. You will, of course, have 36 lines for 1 March which form a patch. You will have 36 lines for 2 March which form another patch and so on BUT you have only 9 lines for
