Re: Size of Analemmatic
Claude, With all the talk about how big an analemmatic dial should be it struck me that it could be of NO consequence! The analemmatic is an azimuth dial. If your shadow does not reach the numerals then walk your shadow until it does! In other words, turn to directly face the direction of your shadow and walk in that direction. Yes, you are right and we took this into account when we talk about overdimensioning the dial. However, I think it is more impressive to see your shadow that really reaches (well, almost...) the dial points. That's why I wanted to lay a step for the date line. Of course the problem is how to instruct someone about how to do this. Some ideas might be: Keep stepping on your shadow Your shadow leads you to the time Follow (or chase) your shadow to the time Those who do it correctly should all get the same time. It might lead some kids to doing strange and interesting things and good questions about what their shadow does. Yes. I'll include this on the instructions plate. A lot of thanks for your suggestions, Anselmo -
Re: On the greatest size of an analemmatic and more
Dear All, I have been following this analemmatic thread with particular interest since I have recently been giving advice to a Swedish stone-cutter who wants to set a dial out in her garden. She lives on the cold side of 60 degrees north. I especially noted: I have been talking to people who know about road construction... So have I and I have been learning about `slab-on-grade construction' and `nominal maximum expected frost depths' and so on. In England, the standard frost depth code is 450mm but in Canada it is typically 1200mm and in places which have really cold winters the figure is 1800mm. In my limited experience, the solution has been to use a truly wonderful material called SAND! This works fine in England. You just dig a shallow pit, put in 150mm or so of sand, lay your slate (or whatever) on top and provided you have been careful this will stay level for many years. When I looked at the Brooklyn bathroom-tile dial that John Carmichael kindly drew to our attention my first thought was, `How will that look after a New York winter?' Worse, `How will it look after 20 or 50 winters?' I am very much minded of the maxim `Beauty is only skin deep'. Can some U.S. reader who knows all about cold winters kindly let this temperate Brit know what is likely to be found underneath this dial? Is there really 1200mm of hard-core and elaborate drainage? My Swedish friend advises that they can expect two to three months of -25C temperatures with occasional dips to -35C. Whenever I have stuck tiles on a bathroom wall I find the wretched things peel off after a year or so inside a nice warm house. With frost heave, ice penetration, and differential thawing effects that the Swedes call `shooting', there wouldn't be much to look at come spring if I had laid the tiles on an outside dial. I am feeling a serious lack of experience! Can anyone help? Frank King Cambridge, U.K. -
Re: Ceiling Dial (was: Satellite Outage)
You also could download my software SONNE from my homepage below. In the submenu of menu Calculations you can generate tabels of EoT with longitude correction included. Input of year and your location is possible. This also could help you. Helmut Sonderegger 47.25 N, 9.59 O Homepage: http://web.utanet.at/sondereh - Original Message - From: Th. Taudin Chabot [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Sent: Monday, April 11, 2005 11:22 AM Subject: Re: Ceiling Dial (was: Satellite Outage) Brooke, The sun is every day exactly South on a different time if you want to be very exact. After 4 years the pattern repeats itself moer or less, but if you want it exact it will be shifted a little bit. But I calculated for this century the mean timeequation for each date and you can use that to find out how much noon is from direct South. Look at http://www.chabot.demon.nl/sundials/sunmeangmt.htm, there is also a downloadable file with the values which you can find at http://www.chabot.demon.nl/sundials/index3.htm Thibaud Chabot At 17:32 10-04-2005, you wrote: Hi: I've been marking the ceiling exactly at noon PST and just also started to include noon PDT. It would be interesting to add a line for when the Sun is South and for the equinox. Can someone email to me a list of for each day for a year from now the exact time when the Sun is South? The mirror on the windowsill is at: 123:09:50.5 N, 39:11:24.6 W, 900 feet above mean sea level. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com - - Th. Taudin Chabot, home email: [EMAIL PROTECTED] - -
Re: On the greatest size of an analemmatic and more
On Mon, 11 Apr 2005, tony moss wrote: Frank King Wrote, Can some U.S. reader who knows all about cold winters kindly let this temperate Brit know what is likely to be found underneath this dial? Is there really 1200mm of hard-core and elaborate drainage? The pedestal of the Longyearbyen dial at 87° north is supported what seems to be the usual way for such frost-beset areas viz. on wooden piles driven 5 metres into the ground. ^^ 78?? Tony Moss. - === Richard B. LangleyE-mail: [EMAIL PROTECTED] Geodetic Research Laboratory Web: http://www.unb.ca/GGE/ Dept. of Geodesy and Geomatics EngineeringPhone:+1 506 453-5142 University of New Brunswick Fax: +1 506 453-4943 Fredericton, N.B., Canada E3B 5A3 Fredericton? Where's that? See: http://www.city.fredericton.nb.ca/ === -
Re: On the greatest size of an analemmatic and more
I have tried two different mosaic methods (i) the standard amateur direct method given in textbooks of siliconing vitreous glass tiles onto an existing slab and then beating in mortar grout; and (ii) using the reverse method, beating in a thin grout layer and then casting a slab on top. We had a week in January with temperatures around -12C at night and -5C daytime, some of the method (i) tiles popped out; the method (ii) tiles were perfect. Research continues! Brian Albinson 49.33 123.06 -
Mosaic Sundial Construction
investigated the two main mosaic construction techniques and have described them in detail on this webpage in the Technical section of the SGS website: http://advanceassociates.com/Sundials/Stained_Glass/TechInfo_files/Tech10.html#Mosaic%20Sundials You can find out more about the mosaic materials and tools used by the experts if you request the free Delphi catalogue at: www.delphiglass.com or call 1-800-248-2048. Reading this catalog will give you much practical information on the materials and tools of the trade and how to use them. It's easier than you might think. Also, your local stained glass shop probably gives classes in mosaic construction and probably sells everything you will need. John A great deal more information can be gleaned from the - Original Message - From: Frank King [EMAIL PROTECTED] To: sundial@rrz.uni-koeln.de Cc: Frank King [EMAIL PROTECTED] Sent: Monday, April 11, 2005 9:19 AM Subject: Re: On the greatest size of an analemmatic and more Dear All, Many thanks to Tony Moss and Brian Albinson for the most erudite comments so far... Tony: I vaguely recall the constructions techniques used in Spitsbergen, namely very deep piles as you note. Here, of course, there is permafrost and one can rely on the ground being permanently frozen below a certain depth which gives stability. I am not sure how this translates when you go to not-quite-so-frozen latitudes a little further south! Brian: I am most interested to hear of your method (ii) for mosaic work. This sounds well worth pursuing. What kind of foundations did you have below the surface? How do you stop water getting into the ground beneath the dial and doing nasty things when it freezes and thaws? Frank King Cambridge, U.K. - -
The posts on the size of an analemmic dial deserve to be edited into an article
This list has again proved its valuewith the discussion of thedimensionsof an analemmatic dial. It is obvious that many membersindependently considered it worthwhile to seek a solution, and note that many ofthe memberswho offered solutions - through a variety of approaches - are among ourdialing heavyweights. I think this question would make a great addition to the NASS FAQ. I'm a little dim on the technical stuff so here the buck gets passed. Would anyone be willing to concatenate these posts and edit them into an article that could be made into web pages? The pages could include or link to any spreadsheets or software etc. The "More" about mounting the various parts should be included separately, andperhaps there are more design and construction considerations that deservemention. Bob Terwilliger NASS Webmaster
Re: Ceiling Dial (was: Satellite Outage)
I wrote an application in PostScript a couple of years ago that printed out the meridian transit times for a particular sundial site. So I dusted it off and put in your longitude and created charts for 2005 and 2006 in PDF format. You can find them at: http://home.comcast.net/~rlh-pr/clarke/meridian-transit-times-2005.pdf http://home.comcast.net/~rlh-pr/clarke/meridian-transit-times-2006.pdf Robert Hough Shadow Master 32.37N 111.13W Hi: I've been marking the ceiling exactly at noon PST and just also started to include noon PDT. It would be interesting to add a line for when the Sun is South and for the equinox. Can someone email to me a list of for each day for a year from now the exact time when the Sun is South? The mirror on the windowsill is at: 123:09:50.5 N, 39:11:24.6 W, 900 feet above mean sea level. Have Fun, Brooke Clarke -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com - This e-mail has been scanned for all viruses by Star. The service is powered by MessageLabs. For more information on a proactive anti-virus service working around the clock, around the globe, visit: http://www.star.net.uk - -
