Concept:
- DISTORTED CONCEPTUAL BASIS:

Above is a summary matrix of the pros and cons of Ring Heliodon methodology. The best method varies with each user and each situation.


Conceptually, this device confuses the perceived relationship between earth and sun. Unlike our experience in real life, the table or earth tilts and rotates via a complicated table mechanism with multiple joints and axes of movement while the "sun" stays in a stationary position mounted on the ceiling of the room. This reversal can be counter-intuitive and it is sometimes difficult to understand the resulting patterns of sun and shadow. Some of this disorientation can be countered with the use of the video equipment described in other areas of this site. In principle, affixing a camera to the table or model will place the user's point of view back on the "earth" that is the table surface and it will once again seem to the camera that the sun is moving through the sky instead of the table undergoing tilting and swiveling motions.

Accuracy:
+ INCREASED DEVICE ACCURACY:
Due to the divergent nature of a point source of light (ie. the sun lamp), the further a model is from the light source, the more accurate the casting of shadows. The design of this device places the sun lamp a reasonable distance from the model (approximately 30'). In addition, a theatrical spot luminaire is used with moderate to high beam control. As a result the accuracy of the shadow casting on this device is reasonably accurate, particularly towards the center of the pool of light projected onto the table surface.
For the greatest accuracy it is best to take the model outdoors into actual sunlight with a sun peg sundial on a clear sunny day. This will place the "sun lamp" approximately 93 million miles away from the model.

Operational Complexity:
- INCREASED DEVICE COMPLEXITY:
Adjusting the device requires understanding and adjusting several movable axes.

Model Complexity:
- FIXED AND STABLE MODEL AND BASE CONSTRUCTION:
Because the table tilts and swivels, models must be constructed to withstand being turned on their edge or even, depending upon the situation, nearly upside down without falling apart. Without pre-planning for change, this limits the ability to quickly modify the model to test for design changes or adjustments. Models also must be built in a manner that allows them to be clamped to the table's surface. This often requires that the model be attached to a large thin base sheet that can accommodate the clamps without damaging the model. This requirement also requires some special accommodations when below grade areas are built into models to be studied.

Model Size:
+ LARGER MODEL SIZE POSSIBLE:
This device will allow larger models to be studied indoors as the table surface is a 2 x 3 foot rectangle. Models can be larger or smaller than this as long as they can be clamped to the table surface (clamps are provided for the device).

Mobility:
- LACK OF DEVICE MOBILITY:
This device must be used in the exact location and configuration for which it was designed.

Weather Dependency:
+ WEATHER INDEPENDENCE:
Use of this method is not dependant upon Muncie weather.

Availability:
- MANAGED USER AVAILABILITY:
Use of this method is restricted by the schedule and policies of the CERES heliodon facility.