What a compatibility report covers

Last updated: April 2026

Astrological compatibility — what astrologers call synastry — compares two birth charts to map how the planets in one person's chart interact with the planets in another's. Where a sun-sign horoscope reads only one planet for each person, synastry reads every planet in both charts and the relationships between them. The result is the difference between a four-word forecast ("Aries and Cancer clash") and a thirty-page narrative that names the actual chemistry, communication patterns, points of friction, and long-term arc between two specific people.

What synastry actually covers

A Celestio compatibility report runs eight sections grounded in the cross-aspects between the two charts. Sun and moon dynamics frame the core temperament fit. Mercury cross-aspects describe how you talk, argue, and decode each other's silence. Venus and Mars together describe romantic and physical chemistry — the most-asked-about layer, and the one sun-sign horoscopes get most wrong. The outer planets (Jupiter, Saturn, Uranus, Neptune, Pluto) describe the long-arc themes — growth, structure, surprise, ideals, and depth — that determine whether a connection deepens over years or burns out fast.

Common patterns and what they mean

We see a handful of patterns in nearly every report. "Magnetic strangers" charts have strong Venus-Mars cross-aspects but weak Mercury contacts — instant chemistry, but the conversation never quite lands. "Best friend" charts run heavy Mercury and Jupiter, light Venus-Mars — easy talk, low spark. "Slow-build" charts pair Saturn contacts with Sun-Moon harmony — the relationship grows on you over months. None of these are verdicts. Synastry is a map, not a prediction; the chart tells you which dynamics to expect, and how to work with rather than against them.

How this differs from a generic horoscope

A generic horoscope reads only the sun and gives advice that applies equally to everyone born in the same month. A Celestio compatibility report reads twenty-plus aspects per chart pairing and gives advice that applies only to the two specific people in the input. We compute the chart at minute precision, surface the timing windows when key transits will activate the synastry (so the report stays useful as the relationship evolves), and write the interpretation in plain English — no jargon, no "Mars trine your moon" without translation. Astrology should be intelligible to the person whose life it describes.

For a primer on the underlying language, see our guide to the 12 zodiac signs or the free Resources hub.

Reading your report well

Read the eight sections in order; later sections build on earlier ones. Don't skip the friction sections — they're the most useful. The growth-edge section names the work the relationship asks of each of you, which is the one thing horoscopes never cover. Bring it to your partner, friend, or co-parent and read it together; the report's value compounds when both people see the same map. If you only know one birth time, the report flags which sections become best-effort — usually the moon-and-house overlays — so you can return and regenerate when you find the missing detail.

Written by the Celestio editorial team. Methodology informed by traditional Western synastry (Rudhyar, Greene, Hand) and refined by interpreting tens of thousands of charts.