🕉️ Ekadashi Reminder & Calendar

A complete Ekadashi calculation system consisting of:

• 🌐 Public Ekadashi API
• 📅 Interactive Web Calendar
• 🤖 Telegram Reminder Bot
• 🔭 Astronomically accurate calculations

This project calculates Ekadashi dates using astronomical moon–sun positions, rather than relying on static tables.

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🌍 Live Demo

🌐 Website

https://hariprajwal.github.io/Ekadashi-reminder/

Interactive interface to:

• Check if today is Ekadashi
• Find next Ekadashi
• View Ekadashi calendar for any year
• Check specific dates

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🔌 Public API

Base API endpoint:

https://ekadashi-api.onrender.com/

This API can be integrated into:

• Mobile apps
• Telegram bots
• Calendar apps
• Websites
• Spiritual reminder systems

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📌 Features

Accurate Ekadashi Calculation

The system calculates Ekadashi using:

• Sun–Moon angular distance
• Tithi calculations
• Arunodaya rule (96 minutes before sunrise)
• Vaishnava / ISKCON fasting rules

Each Ekadashi is classified as:

• 🌕 Shukla Paksha (Waxing Moon)
• 🌑 Krishna Paksha (Waning Moon)

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Telegram Reminder Bot

The bot automatically sends reminders:

• 🌙 1 day before Ekadashi
• 🌅 6 AM on Ekadashi day

Users can also query:

/today
/tomorrow
/next
/year 2026
/check 2026-03-15

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Interactive Website

The website allows users to:

✔ Check today's Ekadashi ✔ Check tomorrow's Ekadashi ✔ Find next Ekadashi ✔ View full yearly calendar ✔ Verify any specific date

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🧠 How Ekadashi is Calculated

Ekadashi is determined by tithi (lunar day).

A tithi is calculated using:

Tithi = (Moon Longitude − Sun Longitude) / 12°

Each tithi spans 12 degrees of separation between the Moon and Sun.

Ekadashi corresponds to:

11th Tithi

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Astronomical Calculation Steps

1️⃣ Calculate Julian day

2️⃣ Get Sun longitude

3️⃣ Get Moon longitude

4️⃣ Compute angular difference

elongation = (moon_longitude - sun_longitude) % 360

5️⃣ Determine tithi

tithi = int(elongation / 12) + 1

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Arunodaya Rule

Vaishnava Ekadashi fasting follows an additional rule:

Ekadashi must be present at:

Arunodaya = Sunrise - 96 minutes

If Dashami overlaps Arunodaya, the fasting day shifts.

This rule ensures the correct observance day.

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📡 API Endpoints

Base URL

https://ekadashi-api.onrender.com

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Check Today

/today

Example response:

{
 "date": "2026-03-15",
 "is_ekadashi": true
}

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Check Tomorrow

/tomorrow

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Next Ekadashi

/next

Example response:

{
 "date": "2026-03-29",
 "paksha": "Shukla",
 "days_until": 14
}

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Ekadashis in a Year

/year/{year}

Example:

/year/2028

Response:

{
 "year": 2028,
 "total": 25,
 "dates": [
   {"date":"2028-01-08","paksha":"Shukla"},
   {"date":"2028-01-22","paksha":"Krishna"}
 ]
}

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Check Specific Date

/check/YYYY-MM-DD

Example:

/check/2026-03-15

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🏗️ Project Architecture

                ┌─────────────────────────┐
                │     GitHub Pages        │
                │   Ekadashi Website      │
                └──────────┬──────────────┘
                           │
                           ▼
                ┌─────────────────────────┐
                │        Render API       │
                │     FastAPI Server      │
                └──────────┬──────────────┘
                           │
                           ▼
                ┌─────────────────────────┐
                │   Ekadashi Calculator   │
                │  Swiss Ephemeris Logic  │
                └─────────────────────────┘

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🧰 Technologies Used

Backend

• Python
• FastAPI
• Swiss Ephemeris
• pytz

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Frontend

• HTML
• CSS
• JavaScript
• GitHub Pages

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Infrastructure

• Render (API hosting)
• GitHub Pages (website hosting)
• Telegram Bot API

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🚀 Deployment

API Deployment

Hosted on:

Render

Start command:

uvicorn main:app --host 0.0.0.0 --port $PORT

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Website Deployment

Hosted using:

GitHub Pages

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📷 Screenshots

(Add images here)

Example:

/images/website.png
/images/calendar.png
/images/api.png

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🔗 Integration Example

Example JavaScript request:

fetch("https://ekadashi-api.onrender.com/next")
.then(res => res.json())
.then(data => console.log(data))

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📅 Example Output

Next Ekadashi:

Date: 29 March 2026
Paksha: Shukla
Days remaining: 14

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📖 Why This Project Exists

Many Ekadashi calendars online:

• rely on static tables
• do not expose developer APIs
• cannot be integrated with applications

This project provides:

✔ Dynamic calculations ✔ Open API ✔ Developer integration ✔ Reminder automation

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🤝 Contributions

Pull requests and improvements are welcome.

Possible future improvements:

• Panchang API
• Moon phase display
• Festival calendar
• Mobile app

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📜 License

MIT License

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🙏 Acknowledgements

Inspired by traditional Vaishnava Panchang calculations and astronomical ephemeris data.

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🕉️

May this project help devotees observe Ekadashi with devotion and awareness.