Hello Ken, The problem of water running down the wall from the footpoint of a pin gnomon can be partly avoided by mounting in the wall just beneath that point a piece of a sloping pipe, cut in the length. Most of the water drops via that half pipe. I have seen this on some old dials with iron styles. More important however is the material of the gnomon. Nowadays iron won't be used anymore. Stainless steel perhaps?
If only the straight hourlines are painted I would prefer a polestyle. The dial can be read over a longer period of time. The shadow of the end of a pin gnomon disappears from the dial at an earlier time. Fer. Fer J. de Vries [EMAIL PROTECTED] http://www.iae.nl/users/ferdv/ Eindhoven, Netherlands lat. 51:30 N long. 5:30 E ----- Original Message ----- From: <[EMAIL PROTECTED]> To: <[email protected]> Sent: Thursday, November 30, 2000 1:46 AM Subject: Gnomon for Vertical Decliner > Gnomon for Vertical Decliner > > I am debating what type of gnomon to put on a 28d SE decliner at 40.15d > latitude, 76.60d W longitude. The perpendicular dial height of 8" should be > enough and would be part of a large painted mural. The artwork will be the > focus, not the gnomon. I do not want to obstruct the view of the dial > center, so I was thinking of just a tapered perpendicular pin and just read > the tip of the shadow. > > I am also considering a pin hole gnomon and just read the spot of light. > I was thinking of attaching the gnomon vertically though, and then coming > out, tilting it to the style angle. I do not believe I've seen any pictures > of sundials done this way. Are there any? I've only seen it at the end of > the style from the dial center. I would have to determine disc and hole size. > > I originally proposed a sundial that included declination lines and > analemma and would work with either type of gnomon. Would either of these > gnomons be appropriate, just for hour lines? The artist I am working with > prefers a more simple design with hour lines only and no other furniture. > So would a more traditional gnomon be better and just read the edge of the > shadow if no other furniture is included? > > Many of the dials I've seen pictured in Europe, are of the style with > bracing on each side. I was wondering how accurately they are installed > without the ability to check with a digital level years ago? I feel the > gnomon needs to be installed first to get the right distance to the dial > center to allow for any distortion when the gnomon is attached so the tip of > the gnomon is in the right location compared to the dial center. I realized > the larger the dial the more fuzzy the shadow becomes. I am just trying to > avoid any added errors. > > I am also concerned about the effects of the attachment points of the > gnomon discoloring the paint from the water running down the wall. I am > considering some type of brass but I am not sure what is the best way to > anchor the gnomon to a masonry wall. I have not really checked out what's > available in hardware or anchors that will not rust or corrode over time. I > do like vertical dials because they are somewhat vandal proof but is there > any way to attach a gnomon that would also be easily repairable if broken > off? > > I was just thinking of having a small permanent hole for the dial center > to aid in laying out the lines now and in the future repaints. I do not know > if this sundial will come to fruition, but I just was wondering if others had > experiences in attaching a gnomon to a wall or suggestions or opinions on > laying out an accurate sundial on a wall so I can be assured that gnomon is > correct and the dial center is truly at the center so my measurements will be > correct when I lay out my lines. > > Thanks in advance, > > Ken Clark >
