Solar arc is defined as the difference between the position of the progressed Sun and natal Sun on any particular day. This arc is then added to every planet and point in the chart. ... You can have a Venus-arc directed chart, vertex-arc directed, ascendant arc directed, etc. This helps you to see many important points of interest about yourself, relationships, and the strongest time of your strengths. It will highlight things that will be issues for you to work on that really effect you, like depression, anger etc. And it helps predict the past, and the future too!
Solar Arc Chart