Recently I’ve been experimenting with the difference between Regiomontanus and Whole Sign houses in horary by recasting published charts with known outcomes in both house systems. On YouTube I came across a horary presented by Peter G. Burns of the Ambrosia Academy of Astrology about a business woman who asked whether her flight would be cancelled due to volcanic ash in the air over Australia. She needed to get to an important business seminar in Sydney. Here is the chart in both Regiomontanus (on the left) and Whole sign (on the right) houses.
Following Lilly, Peter used Regiomontanus houses in which the 9th house of flights has Virgo on the cusp, making Mercury (a natural ruler of travel by air) the significator of the flight. It then becomes necessary to explain the combustion of Mercury by the Sun the the application of Mercury and the Sun to the Moon’s South Node which is in its fall in Gemini. Fortunately, Mercury rules Gemini and has triplicity there, so Mercury is quite dignified. (Although combustion of a significator is usually quite damaging to a horary question, in this case the Sun occupies the domicile of the significator and the effect of combustion is thereby minimized due to the reception.) Apparently this woman was able to take the flight to Sidney and attend her seminar.
The Whole Sign chart is much clearer and easier to interpret. The 9th Whole Sign house is Libra, ruled by Venus in Gemini. Venus is peregrine, but it is a night chart and Venus is the benefic of the sect in power and thus the most auspicious planet in the chart. Venus applies to trine the Ascendant degree and then moves on to trine Saturn, ruler of the Ascendant, showing that the querent will be able to take her flight as planned without impediment.
The mutual reception between Venus (in the term and domicile of Mercury) and Mercury (in the term of Venus) reinforces the interpretation of an auspicious flight (Venus/Mercury). In addition, Mercury’s next aspect is a square to the Part of Fortune at 20 Virgo 50, and Mercury receives the Part of Fortune which lies in Virgo, the domicile and exaltation of Mercury.
It is of some concern that Saturn, which rules the querent, is stationary (not moving) in the 9th of flights. Fortunately, Saturn turns direct in less than 48 hours, which may mean that the flight delays will have ended within two days.
In addition, the protective and beneficial fixed star Spica at 24 Libra 00 conjoins the MC, which lies in the 9th house of flights in the Whole Sign chart and also occupies the term of Venus, which rules the 9th house. Spica conjunct MC in the 9th signifies a favorable business trip.
While both Regiomontanus and Whole Signs give the same answer, the Whole Sign chart (see below) is much more direct and obvious in its answer.