Terms of Service — Hilal Vision
Effective date: 1 January 2026
Last updated: 10 September 2026
Introduction
These Terms of Service ("Terms") govern your access to and use of the Hilal Vision web application (moonsighting.live) and native mobile applications (collectively, "the Platform"), operated by Athrwise Ltd ("we", "us", "our").
Moonsighting.live is operated by Athrwise Ltd, a company registered in England and Wales under company number 17410302, registered office 128 City Road, London, EC1V 2NX, United Kingdom. Athrwise Ltd is registered with the Information Commissioner's Office under registration reference ZC229634. Contact: support@moonsighting.live
By accessing or using the Platform, you agree to be bound by these Terms. If you do not agree, you must not use the Platform.
1. Acceptance of Terms
By creating an account or using any feature of the Platform, you confirm that:
- You are at least 13 years of age (or the minimum age of digital consent in your jurisdiction)
- You have read, understood, and agree to be bound by these Terms and our Privacy Policy
- You have the legal authority to enter into this agreement
2. Description of Service
Hilal Vision is a precision astronomical platform providing:
- Crescent moon (hilāl) visibility predictions using the Yallop (1997) and Odeh (2004) criteria
- Interactive 3D globe and 2D global visibility maps
- Hijri calendar tools (Astronomical, Umm al-Qura, and Tabular engines)
- Historical crescent observation data from the ICOP archive
- Local horizon simulation and moon phase dashboard
- Community-sourced sighting reports
- Eclipse tracking and astronomical ephemeris
Scientific Disclaimer
Hilal Vision is a scientific instrument, not a religious authority. All visibility predictions are mathematical calculations based on established astronomical criteria. They are intended to inform and assist — they do not constitute religious rulings (fatwā) on the commencement of Islamic months. Final determination of Islamic calendar dates in your community rests with the appropriate religious authority.
Crescent visibility predictions inherently involve uncertainty due to atmospheric variability, observer conditions, and the statistical nature of the underlying models. Predictions should not be relied upon for safety-critical applications.
3. User Accounts
Registration
Certain features (sighting reports, Pro access, push notifications) require an account. You agree to provide accurate, current, and complete information during registration and to keep this information updated.
Account Security
You are responsible for maintaining the confidentiality of your account credentials and for all activities under your account. Notify us immediately via the Contact page if you suspect unauthorised access.
Account Termination by User
You may request deletion of your account at any time by emailing support@moonsighting.live with the subject Data Protection — Erasure. Upon deletion:
- Your personal data is removed within 30 days (per our Privacy Policy)
- Public sighting reports you submitted may be retained in attributed/anonymised form as part of the community observation dataset
- Pro subscription benefits cease at the end of the current billing period (no pro-rated refund for remaining time, except as required by law)
Account Suspension by Us
We reserve the right to suspend or terminate accounts that violate these Terms, engage in abuse (spam, fake sighting reports, API scraping without authorisation), or engage in activity harmful to other users or the Platform.
4. Pro Subscription & Payments
Billing
Pro subscriptions are billed in advance on a monthly or annual basis, or as a one-time lifetime payment, depending on your selected plan. All prices are displayed in-app and are subject to applicable taxes.
Payment Processing
Payments are processed by Stripe (web) or Apple App Store / Google Play (native apps). Hilal Vision does not store payment card details. By subscribing, you authorise recurring charges at the applicable rate until cancellation.
Cancellation
You may cancel your subscription at any time. For web subscriptions, open Settings → Subscription → Manage subscription, which opens the billing portal where you can cancel, change your payment method, or download invoices; you can also email support@moonsighting.live with the subject Support — Cancellation. App Store / Google Play subscriptions are cancelled through the relevant store. Cancellation takes effect at the end of the current billing period — you retain Pro access until then.
Refunds
- Web subscriptions: You may cancel within 14 days of your initial subscription and receive a full refund. Submit a request via the Contact page or email support@moonsighting.live.
- App Store / Google Play subscriptions: Refunds are handled by Apple or Google respectively, per their refund policies.
- Lifetime subscriptions: Non-refundable after 14 days from purchase.
Price Changes
We reserve the right to change subscription pricing with 30 days' notice. Existing subscribers are notified via email and in-app notification. Continued use after the effective date of a price change constitutes acceptance of the new price.
One-Time Donations
Donations are voluntary and non-refundable. They do not create any contractual obligation on the part of Hilal Vision.
5. Acceptable Use
You agree to use the Platform only for lawful purposes and in accordance with these Terms. You must not:
- Submit false or fabricated sighting reports
- Attempt to circumvent rate limits, access controls, or subscription paywalls
- Scrape, crawl, or systematically download Platform data without prior written consent
- Reverse engineer, decompile, or disassemble any part of the Platform
- Use the Platform to transmit malware, spam, or any harmful content
- Impersonate another person or misrepresent your affiliation
- Use automated tools to submit sighting reports or interact with the API beyond permitted rate limits
- Violate any applicable law or regulation in connection with your use of the Platform
Violation of these terms may result in immediate account suspension without notice.
6. Sighting Reports — Community Content
Ownership & Licence
By submitting a sighting report, you grant Hilal Vision a worldwide, royalty-free, perpetual licence to publish, display, and distribute your report content (including display name, location, and sighting data) as part of the Platform's community observation dataset.
Accuracy
You represent that all sighting reports you submit are genuine observations made by you personally. Deliberately false reports undermine the scientific integrity of the dataset and are a violation of these Terms.
Moderation
We reserve the right to remove or flag sighting reports that appear implausible (e.g., reported in Zone F, i.e., when the Moon is below the horizon), violate these Terms, or are flagged by the community.
Research Use
Aggregated, anonymised sighting data may be shared with academic researchers studying crescent visibility or Islamic calendar determination, consistent with our Privacy Policy.
7. Intellectual Property
Platform Content
The Hilal Vision brand, logo, UI design system, code architecture, and proprietary data processing algorithms are the exclusive property of Hilal Vision, protected by copyright, trademark, and other applicable intellectual property laws.
You may not copy, modify, distribute, sublicense, sell, or create derivative works based on any part of the Platform without our prior written consent.
Third-Party Attribution
The Platform incorporates third-party open-source software and data used under their respective licences:
- astronomy-engine (Don Cross) — MIT Licence
- MapLibre GL — BSD Licence
- Drizzle ORM — Apache 2.0
- ICOP observation data — used with attribution to the International Astronomical Center
- Yallop (1997) and Odeh (2004) criteria — published scientific formulas in the public domain; Hilal Vision's implementation is original
Full attribution is provided on the About page.
User Feedback
Any feedback, suggestions, or ideas you submit regarding the Platform may be used by us without obligation, compensation, or attribution.
8. Disclaimers & Limitation of Liability
No Warranty
The Platform and its content are provided "as is" and "as available" without warranty of any kind, express or implied, including but not limited to warranties of merchantability, fitness for a particular purpose, accuracy, or non-infringement.
We do not warrant that:
- Crescent visibility predictions will be accurate under all atmospheric and observational conditions
- The Platform will be uninterrupted, error-free, or free of harmful components
- The Hijri calendar dates presented will match the official dates announced by any Islamic authority
Limitation of Liability
To the maximum extent permitted by applicable law, Hilal Vision shall not be liable for any indirect, incidental, special, consequential, or punitive damages, including but not limited to:
- Losses arising from reliance on crescent visibility predictions for religious, travel, or other decisions
- Service interruptions or data loss
- Errors in astronomical computations
Our total aggregate liability for any claim arising from use of the Platform shall not exceed the amount you paid to Hilal Vision in the 12 months preceding the claim.
Religious Determinations
Hilal Vision expressly disclaims any liability for decisions made by individuals or communities based on its predictions regarding the commencement of Islamic months, Ramadan, Eid, or any other religious observance.
9. Third-Party Links & Services
The Platform may contain links to external websites or services (e.g., scientific publications, ICOP, Open-Meteo). We are not responsible for the content, privacy practices, or availability of third-party sites. Accessing them is at your own risk.
10. Governing Law & Dispute Resolution
These Terms are governed by the laws of England and Wales, without regard to conflict of law principles.
Any dispute arising from these Terms or your use of the Platform shall first be subject to good-faith negotiation. If unresolved within 30 days, disputes shall be submitted to the exclusive jurisdiction of the courts of England and Wales.
11. Changes to These Terms
We may update these Terms from time to time. We will provide at least 14 days' notice of material changes via:
- In-app notification to authenticated users
- An updated "Last updated" date on this page
Continued use of the Platform after the effective date of changes constitutes acceptance of the updated Terms. If you do not agree with material changes, you should discontinue use and delete your account before the changes take effect.
12. Miscellaneous
Entire Agreement
These Terms, together with the Privacy Policy, constitute the entire agreement between you and Hilal Vision regarding the Platform, superseding any prior agreements.
Severability
If any provision of these Terms is found invalid or unenforceable, the remaining provisions continue in full force and effect.
Waiver
Failure to enforce any provision of these Terms does not constitute a waiver of our right to enforce it in the future.
Assignment
We may assign these Terms or any rights hereunder without restriction. You may not assign your rights or obligations under these Terms without our prior written consent.
13. Contact
For questions, complaints, or legal notices:
Email: support@moonsighting.live
Contact page: moonsighting.live/contact
Subject line to include: Terms — [Your Query]
Response time: Within 30 days