Another type of aspectarian, also known as a dial, is a circular device used by astrologers to aid in locating aspects in a chart visually. When a chart is cast by hand, the final step of the process is to locate the interrelationships among the various points in the chart by angularity on the 360 degree ecliptic. For example, a planet at 16 degress of Taurus is square (90 degrees angular relationship) another planet at 18 degrees of Leo (a total of 92 degrees separation with a 2 degree orb). The process for determining this is by calculating the distance arithmetically. Since Leo is three signs from Taurus, each sign being 30 degrees, then Leo is 90 degrees, or square, from Taurus. By superimposing the aspectarian upon the chart, one can easily see that the two planets are square to one another without performing any calculations. Therefore the aspectarian helps to visualize the aspects as opposed to an arithmetical approach.
In other cases, however, the arithmetical approach may not be suitable, as is the case with the quintile aspect, for example. The quintile is derived by dividing the ecliptic by 5, yielding 72 degrees. An example would be a planet at 19 degrees of Gemini quintile another planet at 0 degrees of Virgo (71 degrees separation with a 1 degree orb). This scenario better illustrates the value of an aspectarian since the aspect cannot easily be determined by counting the signs involved. An aspectarian would reveal this information in a chart visually.
Nowadays, with the widespread use of computerized charts, this type of aspectarian has become mostly obsolete. Modern astrology software can compute the aspects in a chart and draw aspect lines to illustrate the interrelationships visually. It is still, however, used in Uranian Astrology and Cosmobiology, which utilize the 90 and 45 degree dials.