Composite Options

The "Composite Options" dialog allows you to enter the relevant details for Solar Writer to calculate a Composite chart for the currently opened charts.

The items displayed for Composite Options are twofold:

a)Combined Chart type

b)Midpoint house cusps

Composite Chart type

A Composite (combined) chart can be calculated in more than one way by using different methods, giving rise to more than one type of composite chart. The most common type is the "Midpoint" chart.

With any two charts each chart will naturally have its own points, angles and house cusps. If we take the same point, angle or house cusp (one item at a time) from each chart, we will have two possible points in the zodiac that are exactly equidistant between these two items.

For example Venus in each person's chart, unless in a tight conjunction, will be in a different sign, or at least degree, in the zodiac. And unless they are exactly opposite each other in the zodiac (i.e. in an opposition) the distance between the two Venuses will be shorter on one side of the zodiac than the other. For the Midpoint method we divide the shortest zodiacal distance between them exactly in the middle - this is known as the short-arc (or near) midpoint, and this position in the zodiac becomes the position of Venus in the Composite chart (if we are using the Midpoint method). This process is followed for all the planets, angles, house cusps and other points.

Another method is the "Davison Relationship".  This method of combining charts doesn't involve any of the components of the two charts themselves. Rather it is a midpoint in "time and space". The way this is arrived at is to find the closest halfway point between the two geographic locations (longitude & latitude) of each chart, and then the exact point in time between the two chart times (date & time). These become the time and place of the Composite chart, which is then calculated using these in the normal fashion.

Choose the Composite Chart type you want to generate:

•Midpoints

•Davison Relationship

Midpoint House Cusps

This is only related to the calculation of "Midpoints" type composite charts. In most cases the calculation of these charts is straightforward, and the house cusps of the chart are simply the midpoints of the same house cusps in the two base charts. However, if the house cusps of the two base charts are almost diametrically opposed, then it is possible that a chart made up of the short-arc midpoints of the base chart’s house cusps will have its cusps out of zodiacal order. When this happens, Solar Writer will adjust some of the house cusps to be long-arc midpoints instead of short-arc in order to preserve the correct zodiacal ordering of the houses. In the "Options" menu, "Composite Options"  you can specify any of the three following ways that this adjustment is to be made...

•Auto Anchor - The 1st and 10th house cusps of the base (opened) charts are tested to see which one has the “strongest” composite midpoint, and then that cusp is taken as a short-arc midpoint, and other house cusps adjusted as required to maintain correct zodiacal order of the cusps. The “strongest” midpoint is the one in which the short-arc difference in angle between the cusps on the two base charts is a minimum.

•Anchor on the 1st - The 1st house cusp is always taken as the short-arc midpoint, and other house cusps adjusted as required to maintain correct zodiacal order of the cusps.

•Anchor on the 10th - The 10th house cusp is always taken as the short-arc midpoint, and other house cusps adjusted as required to maintain correct zodiacal order of the cusps.