Astrology App Comparison
How Cosmic Ascendant compares to Co-Star, The Pattern, and TimePassages — feature by feature.
Overview
Cosmic Ascendant is a scientific astrology platform built by professional astronomers. It differs from other astrology apps in several key ways: it uses a custom-built astronomical calculation engine rather than licensed third-party software, it provides uncertainty-aware natal charts that flag borderline placements, it generates personalized imagery from NASA satellite data through its Birth Zenith feature, it offers a Big Three prediction quiz that predicts zodiac signs from personality alone, and its circles bring family and friends into one shared week — with deep pair readings computed from both full charts, and a privacy rule that no one ever sees anyone else's raw birth data.
The comparison below examines how each app approaches core astrology features. All information reflects publicly available features as of August 2026. The comparison aims to be factual; each app has strengths for different use cases.
Feature Comparison
Calculation engine
How planetary positions and chart data are computed.
Cosmic Ascendant
Custom-built astronomical engine using professional-grade ephemeris data (JPL DE430). All calculations performed from scratch.
Co-Star
Uses a licensed third-party astrology calculation library.
The Pattern
Proprietary algorithm. Calculation methodology not publicly documented.
TimePassages
Uses the Swiss Ephemeris library, a widely used open-source ephemeris.
Birth chart accuracy
Whether the app accounts for birth time and location uncertainty.
Cosmic Ascendant
Uncertainty-aware charts. Shows stability indicators, flags borderline Rising signs, and offers a precision resolution process if birth location is too broad.
Co-Star
Standard chart calculation. Does not flag uncertainty or borderline placements.
The Pattern
Does not provide a traditional natal chart wheel. Focus is on pattern-based personality insights.
TimePassages
Standard chart calculation with detailed aspect tables. No uncertainty indicators.
Birth Zenith (stars overhead at birth)
Visualization of the actual sky directly above the birthplace at the moment of birth.
Cosmic Ascendant
Yes. Generates a personalized image using NASA WISE infrared satellite data showing the actual stars, galaxies, and nebulae at the user's zenith point. Automatically catalogs and interprets identified objects.
Co-Star
Not available.
The Pattern
Not available.
TimePassages
Not available.
Big Three personality quiz
A quiz that predicts Sun, Moon, and Rising signs from personality alone.
Cosmic Ascendant
Yes. A 22-question trait-based quiz that maps behavioral patterns to zodiac sign probabilities with real-time heatmap visualization on a zodiac wheel.
Co-Star
Not available. The app requires birth information upfront.
The Pattern
Not available. The app requires birth information upfront.
TimePassages
Not available. The app requires birth information upfront.
Daily horoscope personalization
How daily readings are generated and personalized.
Cosmic Ascendant
Fully personalized transit readings computed from the complete natal chart. Each reading is unique to the user, generated using astronomical calculations of current transits against every natal placement.
Co-Star
Personalized based on full natal chart. Generated using AI with a social media-inspired tone.
The Pattern
Timing-based insights personalized to birth chart. Focuses on psychological patterns and cycles rather than traditional transit descriptions.
TimePassages
Personalized transit interpretations based on full natal chart. More traditional astrology writing style.
Interactive chart builder
A step-by-step educational chart building experience.
Cosmic Ascendant
Yes. A 7-stage progressive builder that teaches how birth year, month, day, time, and location each affect chart accuracy. Shows animated uncertainty arcs that narrow as information is added.
Co-Star
Enter birth details, chart is generated. No progressive educational walkthrough.
The Pattern
Enter birth details. No chart wheel provided; insights are text-based.
TimePassages
Enter birth details, chart is generated. Provides detailed chart interpretation but no animated builder.
How readings are written
Where the words come from, and what they are based on.
Cosmic Ascendant
Readings are written by a language model FROM computed chart geometry — transits, aspects, and placements calculated first, then interpreted. The astronomy is never invented, and every reading is unique to the chart it describes.
Co-Star
Uses AI/LLM to generate daily horoscope content with a distinctive direct, blunt tone.
The Pattern
Primarily uses proprietary algorithms for timing-based insights. Reading style is more formulaic.
TimePassages
Uses pre-written interpretive text by professional astrologer Hank Friedman. Not AI-generated.
Platforms
Where the app is available.
Cosmic Ascendant
Web (PWA), iOS, and Android. The web app can be installed on any device.
Co-Star
iOS and Android native apps. No web app.
The Pattern
iOS and Android native apps. No web app.
TimePassages
iOS, Android, macOS, and Windows desktop application.
Free tier and pricing
What is free, and what a subscription costs.
Cosmic Ascendant
Free with no account: the daily sky reading, the week's sky chart, the Big Three quiz, and the chart builder. Free with an account: your natal chart, a personal reading every Monday, a monthly horoscope, and small circles. Supporter is $6.99/month or $59.99/year (about $5/month), with a 7-day trial.
Co-Star
Full natal chart, daily horoscope, and compatibility features included free.
The Pattern
Basic timing insights and personality profile included free.
TimePassages
Basic chart with limited interpretations free. Full readings require purchase.
Friends, family, and compatibility
How the app handles the people around you — shared charts, pair readings, and group features.
Cosmic Ascendant
Circles for family and friends: keep charts for the people you love, see everyone's week in one Monday email, and read deep synastry between any two members — computed from both full charts, not sun signs. Privacy-first: circle members see derived readings, never anyone's raw birth data. One subscriber expands a circle to 25 people for everyone in it.
Co-Star
Friend system, compatibility readings, group charts, and social feed. Strong emphasis on social features.
The Pattern
Relationship timing insights for connections. Bond feature for comparing charts with others.
TimePassages
No social features. Designed as a personal reference tool.
Which App Is Right for You?
- Choose Cosmic Ascendant if you want scientific rigor: custom astronomical calculations, NASA satellite imagery of your birth sky, uncertainty-aware charts, readings computed from real transit data — and circles that hold charts for your family and friends, with deep pair readings between any two of them.
- Choose Co-Star if you want a strong social experience with friend compatibility, group charts, and daily updates with a distinctive blunt voice.
- Choose The Pattern if you prefer psychological and timing-based insights over traditional chart interpretation, and want relationship-focused features.
- Choose TimePassages if you want a traditional desktop-grade astrology reference tool with detailed written interpretations by a professional astrologer.
Try Cosmic Ascendant
Start with the free Big Three Quiz to predict your Sun, Moon, and Rising signs, or build your natal chart with our interactive chart builder. No account required.