Frequently Asked Questions

What is Moon API?

Moon API is a RESTful API service that provides accurate lunar data, including moon phases, positions, and related astronomical calculations. It's designed for developers who need reliable lunar information for their applications.

How accurate is the data?

Our calculations are based on precise astronomical algorithms and are accurate to within ±1 minute for timing calculations and ±0.1% for illumination values. The data is regularly verified against astronomical observations.

Do you offer a free tier?

Yes, we offer a free tier with 500 requests per day. This is perfect for testing, development, or small-scale applications. Check our pricing section on the homepage for details about our paid plans.

What authentication method do you use?

We use API key authentication through RapidAPI. Your API key should be included in the request headers as 'X-RapidAPI-Key'. Never share your API key or expose it in client-side code.

What response formats are supported?

All API endpoints return data in JSON format, except for the /calendar endpoint which can return either markdown or HTML format. The responses are consistently structured and well-documented in our API reference.

Are there rate limits?

Yes, rate limits vary by plan:

• Basic: 500 requests/day, 1 request/second
• Pro: 1,000 requests/day, 5 requests/second
• Ultra: 10,000 requests/day, 100 requests/second
• Mega: 100,000 requests/month, 200 requests/second

What endpoints are available?

We offer five main endpoints:

• /plain-text - Moon phase name as plain text (not JSON)
• /basic - Phase name, stage, and next phase timing
• /advanced - Detailed data with position and times
• /calendar - Monthly/yearly moon phase calendar
• /emoji - Current moon phase emoji

See our docs.apiReference for detailed documentation.

Can I use the API in a mobile app?

Yes, but we recommend making API calls from your backend server rather than directly from mobile clients to protect your API key. See our best practices guide for more information.

Do you provide SDK or client libraries?

While we don't maintain official SDKs, our API is RESTful and can be used with any HTTP client. We provide code examples in multiple languages in our examples guide.

What location data is supported?

The /advanced endpoint accepts latitude (-90 to 90) and longitude (-180 to 180) coordinates for location-specific calculations. If not provided, it defaults to London coordinates (51.5074, -0.1278).

Location precision by plan:

• BASIC: Default coordinates only (London) — no custom coordinates allowed
• PRO: Coarse precision — coordinates rounded to 0.1° (≈ 11 km)
• ULTRA: Full precision — coordinates retained as provided (no rounding)
• MEGA: Full precision — highest accuracy (no rounding)

What date ranges are supported?

The calendar endpoint supports dates from 1900 to 2100. For other endpoints, historical and future data limits vary by plan:

• Basic: 30 days historical/future
• Pro: 1 year historical/future
• Ultra: 2 years historical/future
• Mega: 27 years historical/future

How often is the data refreshed?

Data refresh rates vary by type:

• Position data: Every 5 minutes
• Phase calculations: Every hour
• Ephemeris data: Daily
• Historical data: Cached for 30 days

What algorithms are used for calculations?

We use several high-precision astronomical algorithms:

• Jean Meeus' algorithms for lunar position and phase calculations
• VSOP87 theory for solar position calculations
• IAU 2000B precession-nutation model
• Atmospheric refraction corrections using Bennett's formula
• Topocentric parallax corrections for observer location

How accurate is the position data?

Our position calculations provide:

• Altitude: Accurate to ±0.1 degrees
• Azimuth: Accurate to ±0.1 degrees
• Distance: Accurate to ±1 km
• Phase angle: Accurate to ±0.1 degrees

All calculations include corrections for:

• Atmospheric refraction
• Topocentric parallax
• Light-time correction
• Aberration

How do I get support?

For technical support, you can:

• Check our comprehensive Documentation
• Contact us through RapidAPI's support system
• Visit our API Status for service updates

How often is the API updated?

We regularly update our calculations and add new features. You can track all changes on our changelog page.

What is your uptime guarantee?

We maintain a 99.9% uptime SLA for paid plans. You can check our current and historical uptime on our status page.