Terms of Use

1Agreement to these terms

These Terms of Use (“Terms”) are a legal agreement between you and Zydeno, the developer of Umbraday (“we”, “us”). They apply to the Umbraday app for Android, its updates and everything it shows or produces (together, “the app”). By installing, opening or using the app you accept these Terms. If you do not accept them, do not use the app and uninstall it.

The Privacy Policy explains how the app handles data and forms part of these Terms. If we offer optional features under additional terms in the future, for example paid features, those terms will be shown to you before you accept them and will apply together with these Terms.

You must be old enough to enter into a binding contract where you live, or use the app with the consent and supervision of a parent or guardian who accepts these Terms for you. If you use the app for an organisation, you confirm that you may accept these Terms on its behalf; the consumer-protection provisions of these Terms apply only to consumers.

2Who provides Umbraday

Umbraday is developed and published by Zydeno (“we”, “us”), an independent developer. Contact: support@zydeno.com, website zydeno.com.

Umbraday is an independent app. It is not affiliated with or endorsed by NASA, the American Astronomical Society or any government agency. Children must be supervised by an adult at all times when watching an eclipse.

3What Umbraday is

Umbraday is an offline guide and chronometer for the total solar eclipse of 2 August 2027 and other eclipses included in the app. You choose a place; the app calculates on your phone the contact times (first to fourth contact), the length of totality, the Sun’s height and related figures, shows them on a map, and can play voice, tone and vibration cues, send optional reminders and print a contact card. It works offline, has no ads and needs no account.

Free. No ads, no tracking, no account.

The current version of the app is provided at no charge and has no ads or in-app purchases. This describes the current version only; see §15 for how this may change.

4Eye safety

This summarises public guidance from NASA and the American Astronomical Society (see NASA and AAS). It is not medical advice. If you are concerned about your eyes, contact an eye care professional.

You should understand the following about the app:

• Umbraday does not protect your eyes. It does not guarantee your eye safety or anyone else’s, and it is not a safety device. Only a proper solar filter, used correctly, protects your eyes during the partial phases.
• The app cannot check your equipment. It cannot tell whether a filter or viewer is genuine, meets ISO 12312-2, is undamaged or is fitted correctly. That is entirely your responsibility.
• Cues and times are estimates. A voice, tone, vibration, notification or on-screen message such as “Totality expected now” is a calculation with an error margin, not an observation of the Sun. It can come early, late, be inaudible or not come at all (see §5 and §7). The moment to take your filter off is decided by what you see: the Moon must completely cover the Sun’s bright surface. When any bright part of the Sun reappears, put your filter back on, even if the app has not told you to.
• Near the edge of the path, totality may be very short or may not happen. If you are near the edge, or your position is uncertain (for example when using approximate location), the app gives no “filter off” hint and tells you to keep your filter on unless you clearly see the Sun completely covered.
• The app gives no “filter off” hint for partial or annular eclipses, for places outside the path of totality, or for events whose checks have not been completed. For those, keep your filter on for the whole eclipse.
• Never use optics without a filter. Do not look at the Sun through a camera, viewfinder, binoculars or telescope unless a proper solar filter is attached to the front. This applies to photo cues and the photo planner in the app too.

The app shows its eye-safety guidance in onboarding, on a card on eclipse day, on a separate screen and as a constant reminder on the eclipse screen. Tapping “I understand” in the app only confirms that you have seen it; it does not change your responsibility or the rules above.

5Accuracy of times and estimates

The figures in the app (contact times, length of totality, the Sun’s height, the edge of the path of totality, distances) are calculated estimates, not measurements and not official predictions. They depend on, among other things:

• the accuracy of the place you give: an approximate location, a rounded or typed coordinate or a map pin can be kilometres off, and near the edge of the path a small error can decide whether totality happens at all;
• your phone’s clock and time-zone data. The app shows UTC next to local time and can warn you when it detects that the clock is manual or off, but it cannot make your clock correct;
• the model assumptions: published eclipse data, an assumed value of ΔT (the difference between Earth’s uniform time and universal time, shown in the app) and a model of the Moon’s outline. Real values can differ;
• conditions the app cannot see: terrain and buildings that hide the Sun, the height of your viewing spot, clouds and weather. Umbraday does not forecast weather, cloud cover or traffic.

Where the app shows an uncertainty (for example “±2 s”), it is a calculated margin for that point, not a promise that the true value lies within it. The app is not an official source, and it is not a substitute for guidance from local authorities, event organisers or professional eclipse guides.

6Not medical advice

Umbraday has no health features. Nothing in the app or on this page is medical advice, a diagnosis or a substitute for an eye care professional. If you are concerned about your eyes, contact an eye care professional.

7Cues, reminders and your phone

Voice, tone, vibration and screen cues, and optional reminders, are conveniences. Do not treat them as an alarm, a timer you can rely on, or a safety system. A cue or reminder may fail, be late, early or silent, for example because:

• the app is not open on the screen (cues play only while Umbraday is open on the eclipse screen; reminders only point you to the app);
• the phone is muted, the volume is low, a Bluetooth speaker adds a delay, or a call or another app takes the audio;
• no text-to-speech engine or voice is installed for your language, so spoken cues are not available;
• battery saving, a low battery, an overheated phone, a restart or a system update stops the app or delays reminders (the app uses inexact reminders);
• the phone’s clock is wrong, or notifications are blocked.

Use the app’s Preflight checks before the day, but keep watching the sky and your filter yourself. The app’s Rehearsal mode uses simulated time and is clearly marked; it is not a prediction of anything. Printed contact cards carry the same estimates and the same eye-safety reminder as the app.

8Your responsibility

You are responsible for:

• following the eye-safety rules in §4 at all times, for yourself and for anyone you supervise, including children;
• obtaining and checking your own solar filters, glasses and equipment;
• checking the place and the clock you give the app, and deciding whether to rely on the figures it shows;
• your travel, accommodation, timing, route and viewing-site decisions, which the app does not make for you. Check local rules, access and road conditions, which may change on the day;
• your own safety and that of others around you, including traffic, crowds, heat and terrain while observing;
• keeping your own backups (see §11).

9Not professional advice; no safety-critical use

The app is a tool to help you plan and calculate. It does not give professional, engineering, legal or other expert advice, and using it does not create a professional relationship with us. You remain responsible for your inputs, for how you interpret the results and for what you decide to do.

Do not use the app as the only basis for a decision where an error could cause death, personal injury, damage to property or the environment, or legal or financial loss, and do not use it in a safety-critical system, in an emergency or to control equipment. The app is not an eye-protection device and does not test or certify any solar filter.

10Licence to use the app

Subject to these Terms, we grant you a limited, personal, revocable, non-exclusive, non-transferable and non-sublicensable licence to download, install and use the app on Android devices you own or control, for your own purposes. The app is licensed to you, not sold.

Except where these Terms, an open-source licence or mandatory law allow it (for example decompiling for interoperability where the law permits), you may not: copy, modify, translate or create derivative works of the app; decompile, disassemble or reverse-engineer it; rent, lend, sell, sublicense, distribute or publish it, or make it available for use by others over a network; remove or change any copyright, trademark or legal notice; or get around any technical limit of the app, including any future purchase, licence or advertising mechanism.

Open-source components and fonts in the app are licensed under their own licences, listed in the app under About → Open-source licenses. Those licences prevail for those components, and nothing in these Terms limits the rights they give you.

11Your data and backups

Your places, journal, checklist, photo plan and settings are stored only on your device. You own them. We do not have a copy and cannot recover them if you lose your phone, uninstall the app, clear its storage or use “Delete all data”. Use the backup export in Settings to keep your own copy. See the Privacy Policy for details, including how location is used.

The files you export or print from your own data are yours to use. We claim no rights in them.

12Data sources, fonts and open-source components

Umbraday is built with published data, open-source software and fonts. Sources and licences are also shown in the app under About:

Viewing guidance referred to in the app is public guidance from NASA and the American Astronomical Society. The data, fonts and libraries remain the property of their authors. Nothing in these Terms limits the rights those licences give you for those components. Umbraday is an independent app and is not affiliated with, sponsored by or endorsed by NASA, the AAS, Google or the other authors named above.

13Acceptable use

You agree not to:

• use the app in breach of any law or of other people’s rights;
• remove or hide legal notices, eye-safety messages or attributions, or present the app’s output as an official, certified or professional service, or as approved by NASA or any authority;
• copy, modify, redistribute, sell or reverse-engineer the app, except as allowed by law or by an open-source licence;
• rely on the app as the only means of protecting your eyes or anyone else’s.

14Intellectual property

The app, its design, text, icon and the name Umbraday belong to the developer, except for the data, open-source components and fonts above, which belong to their owners. Other names are used only to describe things and belong to their respective owners.

15Price, payments, ads and future paid features

Current version. The current version of Umbraday is provided free of charge, without ads and without in-app purchases or subscriptions. This describes the current version only. It is not a promise that the app, or any feature of it, will remain free of charge or free of ads.

Possible changes. We may at any time introduce advertising; offer paid features, in-app purchases, subscriptions or a paid edition; change which features are free; and set or change prices. Features that are free today may require payment in a future version. We will describe such changes in the store listing and release notes, and in the Privacy Policy where they affect data.

Purchases. Any purchase will be made through Google Play and processed by Google under the Google Play Terms of Service and its payment policies. Prices are shown in Google Play before you buy, including taxes where applicable. Subscriptions renew automatically until you cancel them in Google Play; cancelling stops future renewals. Refunds follow Google Play’s refund policies and your mandatory consumer rights, such as the right of withdrawal in the EU and the UK. Where you ask for immediate access to digital content during a withdrawal period, you may lose that right to the extent the law allows, and you will be asked to confirm this before you buy. You are charged only if you choose to buy something.

Ads. If the app shows ads, they are supplied by third parties. We are not responsible for the content of ads or for the products and services advertised, and any dealings with advertisers are between you and them.

Price changes. We may change prices for future purchases at any time. For an active subscription, we will announce a price increase as Google Play and the law require, and you can cancel before it applies.

16Disclaimer of warranties

To the extent permitted by law, the app and everything it produces are provided “as is” and “as available”, without warranties of any kind, express or implied, including warranties of accuracy, completeness, reliability, uninterrupted or timely operation of cues and reminders, fitness for a particular purpose, merchantability and non-infringement. We do not warrant that the calculated times are exact, that totality will occur or last as long as shown at your place, that a cue will sound at a particular moment, or that the app will work on every device or Android version.

17Limitation of liability

To the extent permitted by law, the developer is not liable for any indirect, incidental, special, consequential or punitive damages, or for loss arising from or related to the app, its figures, cues and reminders, or decisions based on them, including a missed, shortened or mistimed totality, missed photographs, travel, accommodation or event costs, loss of data or lost profits, and including harm resulting from not following the eye-safety rules in §4 or from using a filter or equipment that is unsuitable or damaged, even if we were told such loss was possible. Where liability cannot be excluded, it is limited to the extent the law permits.

18Your rights as a consumer

If you use the app as a consumer, you benefit from the mandatory consumer-protection rules of the country where you live, and nothing in these Terms affects them. In particular:

• EU and EEA: your statutory rights, including those on the conformity of digital content and digital services under the national rules implementing Directive (EU) 2019/770 where they apply, and mandatory product-liability rules, remain unaffected.
• United Kingdom: your statutory rights, including under the Consumer Rights Act 2015, remain unaffected.
• Australia: our services come with guarantees that cannot be excluded under the Australian Consumer Law. Where the law allows us to limit our liability for failing to meet a consumer guarantee for services that are not of a kind ordinarily acquired for personal, domestic or household use, our liability is limited to supplying the services again or paying the cost of having them supplied again.
• New Zealand: if you acquire the app for business purposes, you agree that the Consumer Guarantees Act 1993 does not apply, to the extent the law permits.
• United States and Canada: some states and provinces do not allow the exclusion of implied warranties or the limitation of incidental or consequential damages, so some of the exclusions above may not apply to you. In Québec, the mandatory provisions of the Consumer Protection Act apply.

19Indemnity

To the extent permitted by law, you agree to indemnify and hold harmless the developer against claims, liabilities, damages, losses and reasonable costs, including reasonable legal fees, brought by third parties and arising out of (a) your observations and any events or trips you organise for others, (b) your breach of these Terms, (c) your violation of any law or of the rights of others, or (d) output of the app that you provide to another person, such as a client or employer. This does not apply to the extent a claim is caused by our own breach of these Terms or our negligence, or where local consumer law does not allow it.

20Changes, availability and termination

To the extent the law allows, we may change, update, add or remove features, change data sources, and suspend or discontinue the app, in whole or in part or in any country, at any time. We are not obliged to provide updates, maintenance or support, except where mandatory consumer law requires updates to keep the app in conformity.

You may stop using the app at any time by uninstalling it. Your licence ends automatically if you materially breach these Terms, and we may end or suspend it where the law requires. When it ends, you must stop using the app and uninstall it. Your data stays on your device under your control, so export what you need first.

Provisions that by their nature should continue after these Terms end continue to apply, including those on intellectual property, disclaimers, limitation of liability, indemnity, governing law and general provisions.

21Google Play

You obtain the app through Google Play. Your download, and any purchase you make, is also governed by the Google Play Terms of Service and Google’s policies. Where these Terms conflict with Google Play’s terms on the distribution, billing, refunds or licensing of apps obtained from Google Play, Google Play’s terms prevail to the extent of that conflict.

These Terms are between you and the developer only, not Google. Google is not responsible for the app or its content and has no obligation to provide maintenance or support for it. Android and Google Play are trademarks of Google LLC.

22Governing law and disputes

These Terms, and any dispute or claim arising out of or in connection with them or the app, including non-contractual disputes, are governed by the law of the country in which the developer is established, without regard to its conflict-of-laws rules. The United Nations Convention on Contracts for the International Sale of Goods does not apply.

The courts competent for the place where the developer is established have jurisdiction. If you are a consumer, you keep the protection of the mandatory provisions of the law of your country of residence, and you may bring proceedings in the courts of that country where that law allows it.

Before starting formal proceedings, please write to support@zydeno.com and give us at least 30 days to try to resolve the issue informally. This does not affect any time limit that applies to you by law or your right to use an alternative dispute-resolution body available to consumers in your country.

23General provisions

• Entire agreement. These Terms, the Privacy Policy and any additional terms you accept for optional features are the entire agreement between you and us about the app.
• Severability. If a provision is found invalid or unenforceable, it applies to the maximum extent permitted and the rest remains in effect.
• No waiver. Not enforcing a provision is not a waiver of the right to enforce it later.
• Assignment. You may not transfer your rights or obligations under these Terms. We may transfer ours, for example together with the app to another developer; where the law requires, this will not reduce your rights as a consumer.
• Events beyond our control. We are not responsible for failure or delay caused by events beyond our reasonable control, such as outages of networks, devices or third-party services, natural disasters or acts of authorities.
• Export and sanctions. You agree to use the app in compliance with applicable export-control and sanctions laws.
• No third-party rights. No one other than you and us may enforce these Terms.
• Notices. We may give notices in the app, in its store listing or release notes, or on this page. You can send notices to support@zydeno.com.
• Language. These Terms are written in English, which is the binding version. A translation, if offered, is for convenience only, unless the law of your country requires otherwise.

24Changes to these terms

We may update these Terms, for example when we change the app, introduce ads or paid features (§15), or when the law changes. The effective date and version at the top of this page show which version applies, and the version history (§25) summarises the changes.

For material changes we give reasonable notice before they take effect, for example in the release notes or in the app. If you keep using the app after the changes take effect, you accept the updated Terms; if you do not agree, stop using the app and uninstall it. Changes do not apply to disputes that arose before they took effect.

25Version history

26Contact

• Developer: Zydeno, the developer of Umbraday on Google Play
• E-mail: support@zydeno.com
• Website: zydeno.com

See also the Privacy Policy.