If you're planning to buy or construct a sundial, you should read this first: It is NOT possible to have a more accurate sundial than the one you will build from the computer printout we generate from your own Latitude, Longitude, and Time Zone. The angle of each and every timeline on the dial (the sundial's face) must be accurately known and plotted or else gross time errors will be introduced. If your surface is NOT horizontal (such as a wall, monument, or memorial), just send us the compass direction the wall is facing, along with its forward or backward tilt, and in a few days you'll receive all the construction and sundial angles. Complete instructions are included on how to use this data to construct and set up the WORLD'S MOST ACCURATE SUNDIAL. The data will give the angle at which to draw your timeline for each quarter hour of the day. Also, the sine and cosine of every angle is given to facilitate your plotting the dial and verifying your points. A sundial design is suggested and a sample dial drawing is included to guide you.
Here are some of the reasons why our PERSONALIZED SUNDIAL is the only one accurate to a couple minutes:
1. The traditional design of the style (whose shadow determines the time) makes it impossible to know just what portion of the poorly defined shadow to read. This fact alone reveals that no one really expects sundials to be accurate. Our recommended design provides a perfectly straight and accurate shadow which is used to read the time with no judgement errors.
2. The angle the style makes with the dial must be set to a few tenths of a degree. This means the special angle to which the style is set for your home will only give accurate time readings within about 10 or 20 miles of you. Store-bought sundials, marketed throughout the world, are for decorative purposes only.
3. Most all sundials have their noon line pointing exactly North, and their 6am-6pm line exactly east-west. In some places, such as Denver or Memphis, only a few minutes error would be introduced. But such sundials in other places would often be in error by more than a half hour. There'd be an hour error in El Paso, TX, and a 2 hr error in Ft. McPherson, NWT. The only answer is to customize your sundial to your own latitude, longitude, and time zone.
4. The tilt of the earth, and the eccentricity of its orbit about the sun, require a correction to your sundial reading of several minutes depending on the time of year. Four times a year, about April 16th, June 14th, September 2nd, and December 24th, no correction is required. On February 12th, however, 14 minutes is added to the sundial reading, and, on November 4th, 16 minutes must be subtracted. We provide a simple table that will give the correction for any day of the year, any year, and for all latitudes and longitudes.
5. Ordinary sundials are of such an unsound design, and so error-ridden, that seldom is the importance of leveling the dial ever mentioned in the set-up instructions. In our instructions we provide a very simple and very accurate method for leveling your dial. If your sundial will be on a non-horizontal surface, we tell how to mount it, orient it, and give you the exact angles.
Atmospheric refraction of the sunlight will introduce a small error at sunrise and sunset of never more than 3 minutes of time in the middle latitudes. No provision is made for this error since it's so small and so transient, being barely detectable only when the sun is a few diameters from the horizon, where it's usually obscured and when sundials are somewhat less accurate anyway.
PLEASE NOTE: We supply only the personalized data, based on your latitude, longitude, time zone, wall direction and tilt. Though we include an illustrative dial drawing, and suggest a sundial design, we do NOT supply hardware nor plot your dial face since choices and requirements will differ from person to person.
PRICE: $20 (NO LONGER AVAILABLE - But we'll retain this site for your edification.)
When ordering, don't forget to include your time zone and exact latitude and longitude (to at least a tenth of a degree, available at your library), and, if required, your surface's direction/tilt.
PHONE ORDERS (VISA-MC-AMEX-NOVUS): (800)325 2664 FAX: (408)867 6236
Or e-mail: wn@nutri.com
Copyright 1989 by Wholesale Nutrition, PO Box 3345, Saratoga CA 95070
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