Dear Hannes, You said in your first email that your reason for wanting multiple gnomons was to avoid vandalism.
I can't see why a vandal would find a multiple gnomon dial less inviting than a single gnomon dial. But let's assume you are right. You also said that this would be a wall dial. Wall dials that are above the reach of humans are some of the most vandal-resitant of all sundials. How high will the dial be? Is it out of reach? Thx John C. -----Original Message----- From: sundial-boun...@uni-koeln.de [mailto:sundial-boun...@uni-koeln.de] On Behalf Of Frank King Sent: Monday, June 13, 2011 1:01 AM To: "H. Kühtreiber" Cc: sundial@uni-koeln.de Subject: Re: Multignomon Sundial Dear Hannes, Your problem is turning into a bed of nails... > ...the dial I had in mind would be vertical > and facing south-east... That makes the problem more interesting! > ... I can see no way, with my limited abilities, > to get the angles of all those gnomons right. > Any ideas? I imagine that all your gnomons are going to be the same. If you can get ONE right you can get all the others right! Here are two questions: What kind of gnomon you would use if you were making a conventional dial with ONE gnomon? How would you would attach it to the dial? You seem to want some kind of rod gnomon. You can attach that either by drilling a hole or by making up some kind of mounting. It is very difficult to drill a hole that isn't perpendicular to the surface being drilled. It is probably easier to make some kind of mounting. You calculate the sub-style height in the usual way and then design a simple mount. You then go into mass production. All the gnomons have to point in the same direction so you have to have the sub-styles parallel. There is one interesting constraint that you DON'T have... Your hour-lines don't have to radiate from the same point. You could arrange your sundial on a tall thin column with the hour-lines running down, in order, from top to bottom, say from 4h to 14h for a dial that declines south-east. More interesting still, you could have a 24-sided post with the 6h hour-line on the side that faces east and the 12h hour line on the side that faces south and so on. I have a final piece of advice... If you really want to drill lots of holes at awkward angles you are going to need some kind of jig. I cannot think of a good way to design this jig but I am sure there are other list members who can help. All the best Frank King Cambridge, UK --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
