FAQ

This page covers Frequently Asked Questions

Where can I put the sundial?

The sundial needs a level surface with good sun exposure. The surface can be concrete, asphalt, grass or embedded into brickwork.

How big is the sundial?

The size varies according to the latitude the sundial is designed for. To find the approximate size, use the table below.

 

Does your sundial have an outer row of numbers for Daylight Savings Time?

All of our sundials have both an inner and an outer set of numbers. When making a sundial to include DST, do not paint the hour point or circle number. This is because it will then have two sets of points to mark the hour.

The outer numbers can be used or disregarded.

 

Some sundials are confusing. What makes yours easy to read?

We design our sundial with longitude correction.

What is longitude correction in sundial design?

Sundial that are designed with longitude correction are much closer to clock time than sundials without this. For a better explanation,     Click here

Why measure by using triangles?

Triangulation is more accurate when setting out something as large as our sundial. For a better explanation,      Click here

I prefer the Cartesian Coordinate System. Is the sundial also dimensioned in X and Y values?

Our sundial is dimensioned in both triangulation and X and Y vales.

 

 

 

 How long does it take to construct?

This will vary depending on the skill level of the students. The following estimation is based upon students 14 years of age. The survey marks take about 4 hours. (If these are made permanent, this is done only once) The layout and painting of the sundial requires about 2.5 hours.

Cutting and taping the stencils required for painting take about 20 minutes each. However this time can easily be shared throughout the class. For example; A class of 30 students can complete all stencils in 20 minutes.

Is the sundial permanent or temporary?

All of the sundial dimensions are referenced from survey marks which can be made permanent or temporary whether the surface is concrete or grass.

Click here to see the different types of survey points

I want to make the survey marks permanent. What type of screws should I use?

12 gauge stainless steel screws are needed. If it is to be laid out on the concrete, the screws are ¾” or 15mm long.

The concrete must be pre-drilled with either a 3/16” or a 4mm masonry drill bit.

How do I draw the hours and months neatly?

A pdf of the stencils are provided and can be printed out as many times as you like. Simply;

1. Print out the stencils

2. Tape together when required. For example, each month is made up from three pages

3. Cut out the guide holes

4. Paint through the holes

5. Remove the stencil and connect the dots

How do I find true north?

The shadow of a string line at the time the sun reaches ‘high noon’ will show true north. The time of high noon varies according to your longitude and is different for each day. A one year ‘calendar’ will be designed for your longitude and will be supplied with your sundial kit. Detailed instructions can be found on this page.

click here for setup page

Can any age layout the sundial?

The analemmatic sundial is a fun activity for all ages. I have watched a 12th grade layout and construct the sundial with very little supervision. I have also supervised a 3rd grade class during the construction of laying out and painting the hours and months.

The only skills required to construct the sundial is:

  1. The ability to read a tape measure

  2. Ability to paint

I recommend that electrical should be used to mark the measurement. However, if measurement is beyond the ability of the student, a teacher can mark the point on the tape measure for the student.

This is a fun activity and is challenging for all grades! The only difference is the amount of supervision needed. A 12th grade class will find it challenging. However, a second grade class can also construct the sundial as long as the teacher will mark on the tape measure with electrical tape. I have also seen the sundial used for learning about the metric system of measurement.

Finding true north and laying out the four survey markers needs adult supervision.

I’ve heard that analemmatic sundials don’t work very well at the lower latitudes. Why is that?

The closer that you get to the equator, the shorter the shadows will be at noon. I’ll design a sundial for Saudi Arabia, however keep in mind that it doesn’t work so well one hour before and one hour after noon. This isn’t a steadfast rule either because it also depends on the time of year. it could be that it doesn’t work well from 10am to 12 noon.

There is another problem. At the lower latitudes, the month lines start to clash with the hour marks. The sundial below was designed for Weipa Australia. Because of the longitude correction of the dial, the month line didn’t crash into the hour mark. However, this isn’t always the case.

 

Finding north will also require a different method. This is explained in the video below.

 

 

 

 

 

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How do I find North?

Using a magnetic compass, roughly layout the sundial using the dimensions provided. Use a garden hose as the ellipse. A compass only shows magnetic north and this isn’t accurate enough to construct the sundial. However, it is close enough for the preliminary layout and to find true north by using the solar method. After the …

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longitude-correction2

Longitudinal Correction

Our sundial can be designed to show the clock time (LMT) or it can be designed to show Local Apparent Time (LAT) The sundials below are designed for clock time or Local Mean Time. (LMT) Note 1: This dimension is determined by how far away the sundial is from the standard meridian  which is the …

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check-layout

Why measure with triangles?

Triangulation Why dimension in triangles? The Cartesian coordinate system of X and Y values are easier to understand. While they’re easy to understand, they’re hard to use to draw something as big as our sundial. Triangulation is much more accurate for drawing larger scale items. When a carpenter sets out where to place the walls …

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