Interesting Design Question: Sundials, and Mosaics!

I recently picked up a job for a gentleman in Long Island who was referred to me by a collegue. I have a design business in addition to being a teacher at a local college. I specialize in Children’s Spaces and unique design concepts. I’ve consulted on hundred of jobs and really love the work: My most recent job is a nodal center to a new house being constructed not far from Montauk Point Long Island. Here are the specs for the nodal area:

The houseis a double horseshoe shape, the open ends of the horseshoes are facing each other, and the entrance of the house faces South East. I am proposing a mosaic tile feature in the open-air centre that tells time by looking at the position of the sun’s rays on the different mosaics. My drawings are mere sketches as of now, but they need to be complete and a full scale floor plan laid on June 21st, the longest day of the year. There will be direct sunlight hitting the spot, so I am going to need a center structure…preferably cast or hewn from wood or stone. I’m of the stone mind because I enjoy working with it so much…


Of what shape would the center piece most efficiently cast the perfect shadow?
Should there be a cover-over ramada of some sort to project the rays? Possibly, colored glass?

I have never done this type of design before, I have used the sun in some of my designs but never to tell time on a floor. I was hope you all could help me kick around some ideas…

I got this idea originally from a home in Hawaii, that was recently featured on HGTV.

I don’t know if this really meets your design, but it might give you ideas. There’s a sundial in a city park in Houston which has an unusual (to me) design. As shown in the picture, it has stone blocks set in an arc marked with the hours. These could be mosaics flush with the floor. The slightly-different-colored rectangle of tiles in the red-tile oval, is a series of boxes with the names of the 12 months. If you stand on the appropriate month, your shadow points to the correct time. It’s quite accurate and a nice representation of how the angles of the sun change throughout the year. It seems you could replace some of these elements with nice mosaics and each month’s indicator could contain a socket for a movable pedestal used to cast the shadow. The shadow caster could be just a post or a sculpture appropriate to the rest of the decor. A person standing on the block works perfectly well, so you should be free to design any shape you like as long as it casts a pointy shadow from a wide range of angles.

This is probably a standard sundial design for which you could find specifications if you were interested. I know this doesn’t directly address your OP, but I thought you might find it interesting.

The perfect pointer is the lingham, is it not? Oh! er. . . well, maybe not.

(The “pointer” of a sundial is the gnomon.)

One thing to consider about creating a sundial is the location of the house. Does the owner want to have accuarate “sun” time? Eastern Standard Time? Eastern Daylight Time?

Montauk Point is at 41° 04’ 19" N, 071° 51’ 28" W. This means that “sun” noon will be about 12 minutes 38 seconds before noon EST and about 47 minutes 22 seconds later than noon EDT (on June 21). (The house time will be several minutes later than those estimates, depending on how far west of the Point the house is built.)*****

And, of course, at the 41st parallel, shadows at 6 a.m. and 6 p.m. will be North of due West and due East on June 21 and South of due West and East on December 21. You may need to create a general “area” for each hour’s indicator if the homeowner wants to actually tell time by the sundial. This is the problem that the sundial in micco’s link solved by making the observer the gnomon. Rather than moving the “hours,” the sundial moved the gnomon by having a person stand in the correct “month” to cast the proper shadow at different times of year. (If the homeowner just wants a pretty design that shows a general time of day, you can simply set “noon” at “North” and work out whatever design you’d like. If he is looking for an actual timekeeper, you and he need to understand the difficulties of marking “mechanical” time with a “solar” timepiece.)
***** To find the exact Latitude and Longitude of the house, (one way is to) go to:

CLICK on Advanced Find
Then CLICK on Address.
Enter the complete address in the Address Search window and CLICK “GO” (If the program cannot find that address (because it is not yet registered, having no building on the site, enter the address of a neighboring house.)
When the address returns, CLICK on the “Aerial Photo” option. The photo image should have a “push pin” icon near the center of the map. If the push pin is not exactly on the house site, click on the house site to re-center the map. (The “push pin” icon will remain where it was, but the map should shift position to put the site in the center.)
When the house site is in the center of the photo, CLICK the “Info” icon at the top of the web page to get the Lattitude and Longitude (in decimal format) with “crosshairs” marking the house site.

I’m not sure there is an ideal shape for the gnomon. I mean basically all you want is a cast shadow that intersects (or approaches) the hour marker.

How about a phoenix?

I’ve always been interested in building a sundial. This means of course a link. It has some software that plots out sundial markings, though I’ve never dug too deep into that part of the site.

Any chance you’ll throw up a picture of your finalized design Phlosphr?

lingam, not lingham!

I am trying to get in contact with John Ward, leading gnomonist in Australia, I’d like to pick his brain regarding the problem Tom is referring to .
I’ve been in contact with the designer from HGTV and he was very helpful, I even filled out an application to see if they would be interested in this project for their show. So if this happens Grey you will have a lot more than just pics :slight_smile:

Essentially, the client is ex-naval engineer retired very high up the pecking order. He want’s to be able to walk in and see the Time System Flooring and read the time, accurately and subtly. The Time System Flooring is my name for the design I am trying to map out. The problems Tom has mentioned are duly noted and need to be addressed. I still think there is a way to make up for plus or minus 12 minutes for the longest day of the year…I just need to wrap my brain around it for now. I’ll try and find a pic of what I am talking about and post is as soon as I can.

I’ve read about one fascinating type of sundial (although since I don’t have knowledge or practical experience with it I don’t know how difficult it would be). You can easily determine the correct civil time with it. The gnomon isn’t a line - rather, it’s a solid and you read the time from the edges of its shadow. It’s the shape you get when you spin an analemma around its long axis. There’s an example here:

The beauty of this is that the shadow of the gnomon automatically applies the correction from local sun time to civil time. Normally the shadow will cut the the timeline in two places, but you don’t have to know the exact date to know which edge of the shadow to use, just the approximate time of year.

As you can see from the pictures, the timeline is like a section of a circular rim of a wheel where the gnomon is the axle, making it what’s called an equatorial sundial. True, that doesn’t fit in with your desire to put the timeline on the floor. However, it might be possible to use a floor timeline where the shadow of the circular rim would lie if lit from its center. The distance between the hour marks would increase the further away they were from noon, and marks near sunset and sunrise would probably be beyond the floor.

Here’s a link to a description of another sundial of this type: The description claims “The dial indicates true time to within less than a minute, date to the day”.

From a design standpoint, I think it would be interesting to incorporate positive (sunlight) and negative (shadow) casts into the gnomon with transparent and solid space, respectively. This would also allow for the possibility of words or images cast, it could add meaning and transmission beyond a simple shape…meaning in the shadows- in an artistic and symbolic sense. I also think a bit of “Indiana Jones” mystery and intrigue would work well, perhaps prisms in the tile for equinox events or other meaningful or artistic indicators in the mosaic design. I also believe the mystery of a secret incorporated into the design that can only be realized during a certain sun cycle or a piecing together of temporal clues would make your sundial out of the ordinary and akin to other great astronomical monuments like stonehenge… it would have a very elemental texture and be fun and educational all at once…the secrets of the Sun. You would also have the advantage and great novelty of offering this mystery to the owners and the fun and interest of actually solving that secret puzzle. Totally unique, and a great conversation piece.
I wish you much creativity and good luck! Great idea.