quadrants
Helmut, Yes, there are quadrants with straight hourlines. In the bulletin of De Zonnewijzerkring nr 10, october 1981 an overview of quadrants is given by Hans de Rijk. He points to: The Horarium Bilimbatum as published in Protomathesus by Fineus Orontius, 1532. This is noted in Bobinger, Alt-Augsburger Kompassmacher, page 50 where you find a small picture of it. A look alike is in the book Orologi Solari van Girolamo Fantoni, page 366. Another quadrant of this type is made by Metz. Here you also see straight azimuth lines in a separate part of the quadrant. As I think to remember such quadrants are correct for noon. The date scale is constructed according the sun's altiudes at noon. For the other hourlines construct correct points for the solstices and just draw the straight line. These hour lines then are aproximations. I think this also is the fact with quadrants with circular hourlines. Construct the correct noon arc and date scale. For other hour lines construct three points for the solstices and equinox. Just draw the arc through these three points. Best wishes, Fer J. de Vries De Zonnewijzerkring mailto:[EMAIL PROTECTED] http://www.de-zonnewijzerkring.nl Home mailto:[EMAIL PROTECTED] http://www.iae.nl/users/ferdv/index-fer.htm Eindhoven, Netherlands lat. 51:30 N long. 5:30 E - Original Message - From: Helmut Sonderegger [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Saturday, May 31, 2003 10:03 PM Subject: Re: unequal hour lines Sara, in my software, which is also on the NASS-repository, I draw quadrants with temporal hour lines point by point. The circles are aequidistant date lines (not declination lines itself). The hour lines are evaluated by computing the day length of the particular days used and then divided by 12. Then the Sun's altuitude for these hour points is calculated. This method is rather simple for computers, but in this case I guess no simple formula for the hour lines can be found. The type of the resulting hour lines of course depends on the arrangement of the arcs for the date lines or declination lines. In old quadrants aequidistant declination lines are used and then arcs of circles seem to be used for hour lines. As I do not now any literature about the exactness of this construction: Does anybody know such literature? It would be an interesting question too if an arrangement of the date lines can be found where all hour lines become straight lines or at least nearly straight lines. Does anybody know an answer? Helmut Mail: [EMAIL PROTECTED] Web: http://webland.lion.cc/vorarlberg/28/sun.htm -
Re: your webpage
Helmut, No idea why I didn't add the formulas but now they are. Thanks for your remark. Best wishes, Fer. Fer J. de Vries De Zonnewijzerkring mailto:[EMAIL PROTECTED] http://www.de-zonnewijzerkring.nl Home mailto:[EMAIL PROTECTED] http://www.iae.nl/users/ferdv/index-fer.htm Eindhoven, Netherlands lat. 51:30 N long. 5:30 E - Original Message - From: Helmut Sonderegger [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Monday, June 02, 2003 12:52 PM Subject: your webpage Fer, I just had one more look on your webpage with the information on analemmatic sundials. Therefore my question: Why did you not include the formula for the date points of the dial? I know, one can see that very easy from the images there, but perhaps it would be of some help for some visitors of this page. sunny greetings Helmut - -
Re: your webpage
Hi John, Yes, I know and this is why a suncompass works. It's one scale of date with a number of ellipses for different latitudes around it. With one remark. At higher latitudes the length shrinks and final to zero at latitude 90. And look at the formula: y = a cos phi . tan decl a cos phi is constant for a certain dial so y always is proportional to tan decl. But your remark is a very practical help to simplify the job. Best wishes, Fer. Fer J. de Vries De Zonnewijzerkring mailto:[EMAIL PROTECTED] http://www.de-zonnewijzerkring.nl Home mailto:[EMAIL PROTECTED] http://www.iae.nl/users/ferdv/index-fer.htm Eindhoven, Netherlands lat. 51:30 N long. 5:30 E - Original Message - From: John Carmichael [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Monday, June 02, 2003 9:57 PM Subject: Re: your webpage Hi Helmut others: I'm sure you probably know this already, but one neat and helpful thing I learned about analemmatic date line construction is this: All analemmatic dials at every latitude and of every size use the same date line; the only difference is in the length of the line which becomes longer (in relation to the ellipse) at higher latitudes and with bigger dials. But the date line is the same for all. The distance between the date markings is proportionally the same, no matter what length the date line. In other words, you don't have to redraw the date line everytime you design an analemmatic for a different latitude or of a different size. You just need one drawing and you can use it as a template for any analemmaic dial. All you need to do is to change its size. If you use Delta Cad or photocopyers, this is an easy operation. To determine the length of the date line is simple. First, you determine the location of a focus point using traditional methods or Fer's Delta Cad macro. Then draw a horizontal line to the center of the dial (the North/South Meridian). This point is the equinox date on the date line and is at the center of the line. Then draw an angled line from the focus that is 23.44 degrees from horizontal. Where this line crosses the meridian is one end of the date line and marks a solstice date. Measure an equal distance in the other direction an this is the other end of the line and is the other solstice date. The distance between these two points is the length of the line. Then just blow up or shrink the size of your template drawing so that it is the same length. Simple! And this saves a lot of work. Note: Here is a PDF of my Delta Cad Date Line Template. Of course you can change font type and scale if desired. And you can have the option of a clockwise or counterclockwise date notation. Both are shown here. John John L. Carmichael Jr. Sundial Sculptures 925 E. Foothills Dr. Tucson Arizona 85718 USA Tel: 520-696-1709 Email: [EMAIL PROTECTED] Website: http://www.sundialsculptures.com - Original Message - From: Helmut Sonderegger [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Monday, June 02, 2003 3:52 AM Subject: your webpage Fer, I just had one more look on your webpage with the information on analemmatic sundials. Therefore my question: Why did you not include the formula for the date points of the dial? I know, one can see that very easy from the images there, but perhaps it would be of some help for some visitors of this page. sunny greetings Helmut - -
NASS and the Banff Conference
The email, CD, and print editions of the June issue of the NASS Compendium have all been dispatched. If you are a NASS member, then you should be receiving your copy (once again expanded to an additional 4 pages) very soon. For anyone who is considering joining us for the annual conference in spectacular Banff, Alberta Canada: Please note that registration material is also provided with this issue. Because of contractual commitments to the Banff Centre, we need to give a final commitment on the number of rooms very early this time around - so the DEADLINE for registration is JUNE 21. Both NASS and the Banff Centre must have your registrations in hand by that date - and hopefully earlier so that we have some time to decide on the appropriate commitment. If you have been putting off registering because you think there's plenty of time, please think again. Banff is one of the most beautiful spots you will ever see - and this conference promises to be fascinating. Don't miss it by delaying. Register before JUNE 21. Fred Sawyer
your webpage
Fer, I just had one more look on your webpage with the information on analemmatic sundials. Therefore my question: Why did you not include the formula for the date points of the dial? I know, one can see that very easy from the images there, but perhaps it would be of some help for some visitors of this page. sunny greetings Helmut -
Re: your webpage
Hi Helmut others: I'm sure you probably know this already, but one neat and helpful thing I learned about analemmatic date line construction is this: All analemmatic dials at every latitude and of every size use the same date line; the only difference is in the length of the line which becomes longer (in relation to the ellipse) at higher latitudes and with bigger dials. But the date line is the same for all. The distance between the date markings is proportionally the same, no matter what length the date line. In other words, you don't have to redraw the date line everytime you design an analemmatic for a different latitude or of a different size. You just need one drawing and you can use it as a template for any analemmaic dial. All you need to do is to change its size. If you use Delta Cad or photocopyers, this is an easy operation. To determine the length of the date line is simple. First, you determine the location of a focus point using traditional methods or Fer's Delta Cad macro. Then draw a horizontal line to the center of the dial (the North/South Meridian). This point is the equinox date on the date line and is at the center of the line. Then draw an angled line from the focus that is 23.44 degrees from horizontal. Where this line crosses the meridian is one end of the date line and marks a solstice date. Measure an equal distance in the other direction an this is the other end of the line and is the other solstice date. The distance between these two points is the length of the line. Then just blow up or shrink the size of your template drawing so that it is the same length. Simple! And this saves a lot of work. Note: Here is a PDF of my Delta Cad Date Line Template. Of course you can change font type and scale if desired. And you can have the option of a clockwise or counterclockwise date notation. Both are shown here. John John L. Carmichael Jr. Sundial Sculptures 925 E. Foothills Dr. Tucson Arizona 85718 USA Tel: 520-696-1709 Email: [EMAIL PROTECTED] Website: http://www.sundialsculptures.com - Original Message - From: Helmut Sonderegger [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Monday, June 02, 2003 3:52 AM Subject: your webpage Fer, I just had one more look on your webpage with the information on analemmatic sundials. Therefore my question: Why did you not include the formula for the date points of the dial? I know, one can see that very easy from the images there, but perhaps it would be of some help for some visitors of this page. sunny greetings Helmut - Attachment converted: Macintosh HD:ANALEMMATIC DATE SCALE (weeks 1 (PDF /CARO) (00086533)
Re: your webpage
Damn! You're right. I meant to say that. I got it backwards in my letter, but at least I it's right in my head! Thanks for catching my slip up. John - Original Message - From: Mac Oglesby [EMAIL PROTECTED] To: John Carmichael [EMAIL PROTECTED] Sent: Monday, June 02, 2003 2:04 PM Subject: Re: your webpage John, Doesn't the date line get shorter as the latitude increases, shrinking to a point at the poles? Best wishes, Mac Hi Helmut others: I'm sure you probably know this already, but one neat and helpful thing I learned about analemmatic date line construction is this: All analemmatic dials at every latitude and of every size use the same date line; the only difference is in the length of the line which becomes longer (in relation to the ellipse) at higher latitudes and with bigger dials. But the date line is the same for all. The distance between the date markings is proportionally the same, no matter what length the date line. In other words, you don't have to redraw the date line everytime you design an analemmatic for a different latitude or of a different size. You just need one drawing and you can use it as a template for any analemmaic dial. All you need to do is to change its size. If you use Delta Cad or photocopyers, this is an easy operation. To determine the length of the date line is simple. First, you determine the location of a focus point using traditional methods or Fer's Delta Cad macro. Then draw a horizontal line to the center of the dial (the North/South Meridian). This point is the equinox date on the date line and is at the center of the line. Then draw an angled line from the focus that is 23.44 degrees from horizontal. Where this line crosses the meridian is one end of the date line and marks a solstice date. Measure an equal distance in the other direction an this is the other end of the line and is the other solstice date. The distance between these two points is the length of the line. Then just blow up or shrink the size of your template drawing so that it is the same length. Simple! And this saves a lot of work. Note: Here is a PDF of my Delta Cad Date Line Template. Of course you can change font type and scale if desired. And you can have the option of a clockwise or counterclockwise date notation. Both are shown here. John John L. Carmichael Jr. Sundial Sculptures 925 E. Foothills Dr. Tucson Arizona 85718 USA Tel: 520-696-1709 Email: [EMAIL PROTECTED] Website: http://www.sundialsculptures.com - Original Message - From: Helmut Sonderegger [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Monday, June 02, 2003 3:52 AM Subject: your webpage Fer, I just had one more look on your webpage with the information on analemmatic sundials. Therefore my question: Why did you not include the formula for the date points of the dial? I know, one can see that very easy from the images there, but perhaps it would be of some help for some visitors of this page. sunny greetings Helmut - Attachment converted: Macintosh HD:ANALEMMATIC DATE SCALE (weeks 1 (PDF /CARO) (00086533) -
