Chart Angle Progression Type

When charts are progressed, it is normal to progress all the planets according to the prescribed progression rate, but to apply a separate calculation to determine the position of the Midheaven (MC), and then to derive the other chart angles (Ascendant, Vertex, Equatorial Ascendant) from that newly calculated MC. In the "Preferences" dialog, "Progs/Dirns" tab Solar Fire includes 5 different methods by which the MC’s progressed position may be calculated. These methods are as follows...

•True Solar Arc in Longitude - The MC’s longitude is progressed by the same longitude arc as the Sun. This method is possible the most commonly used method today.

•True Solar Arc in Right Ascension - The MC’s right ascension is progressed by the same right ascension arc as the Sun

•Naibod in Longitude - The MC’s longitude is progressed at the rate of the mean motion of the Sun in longitude (this is 0°59’08’’ per day). This method is also widely used.

•Naibod in Right Ascension - The MC’s right ascension is progressed at the rate of the mean motion of the Sun in right ascension (this is 3m56.5s of arc per day).

•Mean Quotidian - The MC is progressed by the same method as the planets, thus moving about 361° per day, as opposed to the Sun’s movement of about 1° per day. This method is also known as “Daily Houses”.

You can select your desired method from the drop-down list. Any progressed charts or dynamic reports involving progressions that are subsequently calculated will use the newly selected angle progressions method. It is possible to determine which angle progression method has been used in a progressed chart by checking the chart type in the chart details text - the chart type description includes the angle progressions method that was used. Similarly, it is possible to determine which rate was used in a dynamic report by looking at the list of selected events in the report header. This contains a description of the progression type, method and rate.