Two charts with the same contact can describe very different lives. Five factors decide which version you get.
Sect comes first. A day chart and a night chart use different Fortune formulas. If the Sun sits above the horizon at birth, the lot is measured from the Moon; if the Sun sits below, it is measured from the Sun. Same birth date, two different degrees, and sometimes two different signs. The calculator is not broken. It is applying a rule, and you need a birth time to know which rule applies to you.
The birth time itself is the second factor, and it is the one people skip. The IC is an angle built on the meridian. No birth time, no reliable angle, no reliable house. A noon chart is a working sketch for a reading, not a measurement, and its angles should never be quoted as fact.
House system comes third, and this is where astrologers genuinely disagree. Most traditions tie the IC to the fourth house, but some house systems place that cusp differently. Treat the fourth-house link as customary interpretation rather than a universal astronomical rule. The conjunction still holds; the address of the theme can move.
Fourth, read the sign on the IC and look at what else occupies that area. A Fortuna-to-IC contact with Saturn nearby turns the story toward duty, legacy and slow-built security in the family. With Pluto involved, the theme becomes power inside shared space, and the home can become a place where control is negotiated. With Venus settled there, the whole thing softens into comfort, beauty and ease. The conjunction does not cancel its neighbours. It joins them.
Fifth, zoom out to the ruler of the IC and the Moon's condition. If the ruler of your fourth house is strong and well-aspected, the fortune-on-foundation story tends to flower: property, family, lineage and private security all cooperate. If that ruler is under pressure, the same contact can translate into restless moves and never quite landing.
One more comparison is worth holding alongside all five. When Fortuna lands on the Descendant instead of the IC, the resonance moves from the private foundation to the relationship axis itself: partnership becomes the arena where fortune gathers rather than the base it rests on. That is a different placement with a different story, so readers weighing how a Fortuna contact shifts from the relationship axis to the private foundation should compare the Descendant Conjunct Fortuna reading directly against this one before deciding which theme dominates their chart.
Finally, remember what kind of number you are reading. In an example calculation, a longitude of 15° against 17° gives a separation of 2° and an orb of 2°. That is the geometry, not a score, and not evidence that anything in particular will happen. A wide orb loosens the contact. An exact one tightens it. Neither one promises a house, an inheritance or a person.
If you have followed the thread this far, you already know the move: calculate, then read the neighbours. A single contact describes one theme. The rest of the chart decides how it lands.