The lunar nodes always move backward around the chart, but their real movements tend to wobble between retrograde and direct motion.

The **mean **calculation smooths out these minor wobbles by producing a mathematical average of the total movement.

The **true **calculation reflects the accurate location of the nodes at a given moment, rather than the mathematical average.

There can be discrepancies between **true** and **mean** calculations of up to 1°45’. For a smattering of people, that’s enough for the nodes to change sign and house depending on which calculation you use.

CHANI app uses the **true **calculation for the lunar nodes. If you’re used to seeing your chart from an astrologer or astrology software that uses the **mean **calculation, it could mean your nodes change sign.

While the true calculation represents the most mathematically accurate location, astrology is a field that tends to make space for less materialist modes of knowing. Just like choosing a house system, many astrologers will decide at the beginning of their practice whether to work with the true or mean nodes.

You can think of it like a chef working in metric or imperial. There’s no “perfect” conversion between a cup of flour and 136 grams unless you’re pouring that cup onto a measuring scale to get the accurate mass. Still, it’s likely to be pretty close.