Monad Calendar Clock vs 天球模擬器
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Monad Calendar Clock
This app visualizes time through planetary and celestial movements, contrasting natural rhythms with mechanical time. It offers unique perspectives on Earth's position in space and time, showing star and planet locations, seasonal changes, and lunar phases.
- Planetary time and date display
- Celestial ring visualization
- Heliocentric and Geocentric modes
- Star and planet location tracking
- Seasonal and lunar phase progression
- Twilight and sunrise/sunset times
- Event scheduling
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MONAD does something that no other clock or calendar does; it tells the planetary time and date – the solar day, lunar month & seasonal year. MONAD reveals your unique place (and perspective) in planet-centered space and time. MONAD demonstrates the biorhythms of the Earth’s biosphere, and it integrates two types of time: 1) Natural time, which is cyclic, variable, and alive, with 2) Mechanical time, which is linear, highly regular, abstract and artificial. MONAD represents a paradigm shift of planetary proportions; A New Paradigm of Time With MONAD, you see the natural rhythms of time proceeding in endless circles and spirals. MONAD shows the location of the stars and planets; what’s visible at night from your location on Earth. MONAD shows the progression of the four seasons and the phases of the Moon; the obliquity of the ecliptic and the Earth’s circle of illumination, and a Twilight Dial tells you the time of Sun rise and Sun set at any latitude and time of year. MONAD shows the agricultural biorhythms of the Earth’s photosynthetic biosphere. MONAD restores the Earth, and the Earth’s biorhythms and biosphere, back to the center of our collective attention and awareness. With MONAD you see the Earth globe from an unusual perspective; the north (or south) polar axial perspective. MONAD automatically places a time zone-spanning Hour Hand at your location on the globe, marking your longitude & latitude, and you see all 24 time zones, all around the globe at the same time, the whole world interconnected. MONAD has four main Modes of operation. Geocentric (Geo) Mode features planet Earth at the center of a time and date-telling, 3-dimensional celestial ring. The algorithms and programming which drive all of the astronomical activity is based on a Sun-centered and highly accurate model of the solar system which you can access in Heliocentric (Helio) Mode. Accelerate through time, into the past or future, and watch how the configuration of the solar system changes. Shift back and forth from Geo to Helio Modes, and it’s easy to see how the two perspectives are related. It’s easy to see how and why the planets have apparent retrograde activity from an Earth-centered perspective. There is so much to explore and learn in MONAD. Astro Mode features a 2-dimensional Calendar-Clock face, which makes it possible to set the time by dragging the hour hand around the dial, or you can set the date by dragging the calendar band, or zodiac band, past the Sun’s meridian or date indicator fixed at noon at the top of the dial. A Table at the top of the screen lists the precise location of the Sun, Moon and planets at any time and date, so basically this Astro screen is equivalent to an astronomy or astrology chart, at any moment in time. Astro Mode will eventually feature a Scientific Astrology Program and an Educational Astronomy Program. Event Mode is where you record and schedule personal events, in the context of important and memorable planetary events we all share. Color-coded Event Wedges are shown in the context of the 4 corners of a solar day (Sun rise, noon, Sun set & midnight), the 4 corners of a lunar month (full and dark Moon, waxing and waning half Moons), and the 4 corners of a seasonal year (equinoxes & solstices). Another unique feature of MONAD is that you can record events “in the Now,” which encourages more presence in your life. A Health Event Mode allows you to see your personal, endocrine biorhythms in the context of planetary biorhythms we all share. The 24 hour circadian Calendar-Clock face is ideally suited to organize and display health events. If you choose to have MONAD integrate with the Apple Health app (HealthKit); then health data (e.g. Sleep period and Steps) read from HealthKit is used for display within the MONAD app. MONAD is beautiful, educational & transformative, and it will change the way you see the world around you, and your place within it. MONAD – A New Paradigm of Time.
天球模擬器
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Astronomy Teaching System is an interactive application designed for learning and exploring basic astronomy. Through visual simulations, it helps users intuitively understand complex celestial geometry and the patterns of celestial motion. Core Features: • Celestial Sphere and Diurnal Motion Simulation: Observe the celestial coordinate system with support for toggling Right Ascension RA and Declination Dec grid lines. Users can freely adjust the observer's latitude 90°N to 90°S via a slider to see real-time changes in the starry sky and stellar tracks at different latitudes. • Dual Perspectives and Relative Motion: Provides Earth Rotation and Celestial Rotation modes, allowing you to thoroughly understand the principles of diurnal motion from different reference frames. You can tap stars on the screen to hide or show specific celestial bodies. • Solar Path through the Seasons: Explore the changing position of the sun on the ecliptic. Use an intuitive date slider 1/1 to 12/31 to observe changes in solar altitude angles and daylight tracks during the equinoxes and solstices. • Space and Earth Mode Toggle: In Space Mode, view Earth's orbital path and axial tilt in the solar system from a bird's-eye perspective. In Earth Mode, view the daily solar path in the local sky from an observer's first-person perspective. • Rotation and Revolution Control: Supports independent toggling of Earth's rotation and revolution, with an acceleration feature for quick demonstrations of long-term astronomical changes. This application offers intuitive touch-to-zoom and perspective adjustment features, making it an ideal supplementary learning tool for students, educators, and astronomy enthusiasts.
Screenshots
Verdict
The clearest difference is price: 天球模擬器 at Free against Monad Calendar Clock's $0.99. 天球模擬器 also leads on update cadence (every 3 days vs every 6 weeks). Monad Calendar Clock's advantage is chart position (#191 vs unranked). On ads, in-app purchases, device support and iOS requirement there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
天球模擬器 is free to download; Monad Calendar Clock costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.
Monad Calendar Clock ships an update every 6 weeks, 天球模擬器 every 3 days. The most recent releases landed on October 29, 2026 and October 25, 2026 respectively.
| Parameter | Monad Calendar Clock | 天球模擬器 |
|---|---|---|
| Price | $0.99 | Free — better |
| Rating | 3.7 (14 ratings) — better | — |
| Positive reviews | 22.2% of reviews | — |
| Number of ratings | 14 — better | — |
| Update frequency | Every 6 weeks | Every 3 days — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | — |
| Best chart rank | #191 — better | — |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 13.0 | 13.0 |
| Further details — not scored | ||
| Size | 266 MB | 19 MB |
| Age rating | 4+ | 4+ |
| Developer | Earth at the Center LLC | Han-Chiang Chou |
In-app purchases
Monad Calendar Clock
No in-app purchases
天球模擬器
No in-app purchases









