Terms of Service

Last updated 23 August 2026

These terms apply when you use the Night Logic iOS app or this website. By downloading or using Night Logic, you agree to them. If you do not agree, please do not use the app.

1. The agreement

Night Logic (the “app”) is published by William Dutton (“we”, “us”). These Terms of Service, together with our Privacy Policy, form the agreement between you and us regarding the app.

Night Logic is distributed through the Apple App Store, so Apple’s Licensed Application End User License Agreement also applies to your use of it. Where these terms and Apple’s standard EULA conflict, Apple’s standard EULA governs for matters it covers.

2. Your licence to use the app

We grant you a personal, non-exclusive, non-transferable, revocable licence to install and use Night Logic on Apple devices you own or control, for your own non-commercial astronomy and astrophotography planning, in accordance with the App Store Usage Rules.

This is a licence, not a sale. We retain all rights not expressly granted.

3. Subscriptions and purchases

What Pro includes

Night Logic is free to download and use. An optional Pro upgrade unlocks the full exposure plan, the extended NGC and IC catalogue, and the multi-night forecast. The exact contents of Free and Pro may change over time as the app develops.

Billing

Pro is offered as a monthly subscription, a yearly subscription, or a one-time lifetime purchase. All purchases are processed by Apple and billed to your Apple Account. Current prices are those shown in the App Store at the time of purchase and vary by region.

Auto-renewal

Subscriptions renew automatically at the end of each billing period unless you turn off auto-renewal at least 24 hours before the period ends. Your Apple Account is charged for renewal within 24 hours of the end of the current period.

Managing and cancelling

Manage or cancel a subscription in Settings › your name › Subscriptions on your iPhone, or through the App Store. Deleting the app does not cancel a subscription. Cancellation takes effect at the end of the current billing period; you keep Pro until then.

Refunds

Purchases are handled by Apple, so refunds are at Apple’s discretion and subject to their policies. Request one at reportaproblem.apple.com. We cannot issue refunds for App Store purchases ourselves. Your statutory rights, where they apply, are unaffected.

Price changes

We may change prices for future billing periods. Where a change affects an existing subscription, Apple will notify you and, where required, seek your consent before the change takes effect.

Restoring purchases

Pro is tied to your Apple Account and can be restored on your devices from within the app. A “lifetime” purchase means it is not a recurring charge and does not expire; it does not constitute a promise that the app itself will be published, supported, or functional indefinitely.

4. Accuracy of predictions

Night Logic combines astronomical calculation, published catalogue data, a third-party weather forecast, and modelled estimates of your equipment’s behaviour. Every output is an estimate.

• Weather and seeing come from forecasts, which are frequently wrong. Seeing and transparency in particular are approximations derived from wind and humidity, not measurements of your sky.
• Sky darkness is estimated from your location and is not based on measured light-pollution data. Your actual site may be substantially darker or brighter.
• Exposure recommendations are starting points based on the specs you entered. Real results depend on your polar alignment, guiding, focus, optical train, filters, sensor behaviour, and processing.
• Catalogue and equipment specifications may contain errors or become out of date.

Nothing in the app should be relied on where accuracy is critical — including for scientific, navigational, professional, or commercial purposes. Verify anything that matters.

5. Safety while observing

Astronomy takes place outdoors, in the dark, often in remote places. You are responsible for your own safety and for that of anyone with you.

• Do not use the app while driving, and do not rely on it for navigation or for assessing whether a site or route is safe to reach.
• Check your own weather and local conditions before travelling. A favourable forecast in the app is not a judgement about road, terrain, or personal safety.
• Never point a telescope, binoculars, camera, or your unaided eyes at the Sun. Doing so can cause immediate and permanent blindness. Night Logic is a night-sky planner and provides no solar observing guidance or safety equipment advice.
• Obtain permission before observing on private land, and follow local rules on access, fires, and overnight stays.

6. Acceptable use

You agree not to:

• Reverse engineer, decompile, or disassemble the app, except where that restriction is prohibited by law.
• Copy, redistribute, resell, sublicense, or make the app or its data available as a service to others.
• Extract or scrape the app’s catalogue or equipment databases for use in another product.
• Circumvent, disable, or interfere with the purchase and entitlement checks that gate Pro features.
• Use the app in violation of any applicable law, or in any way that disrupts the third-party services it depends on.

7. Third-party data and services

Night Logic relies on services and datasets we do not control, including Open-Meteo for weather and geocoding, Apple for geocoding and payments, RevenueCat for subscription entitlements, published astronomical catalogues such as the Messier and NGC/IC catalogues, and open-source astronomical calculation libraries.

We are not responsible for the availability, accuracy, or conduct of those services, and they may change, degrade, or stop being available. If a service the app depends on becomes unavailable, features that rely on it may stop working.

8. Intellectual property

The app, its name, its icon, its interface, its written content, and its compiled datasets are owned by us or licensed to us, and are protected by copyright and other laws. Underlying astronomical facts are not owned by anyone; our particular compilation, presentation, and scoring of them is.

Open-source components included in the app remain under their own licences.

9. Availability and changes

We may add, change, or remove features, and we may stop publishing or supporting the app entirely. We will try to give reasonable notice of anything significant through App Store release notes, but we do not commit to any particular feature remaining available.

10. Termination

You may end this agreement at any time by deleting the app. We may suspend or terminate your licence if you materially breach these terms. On termination, your right to use the app ends; provisions that by their nature should survive — including sections 4, 7, 8, 11, and 12 — continue to apply.

11. Disclaimer of warranties

To the fullest extent permitted by law, the app is provided “as is” and “as available”, without warranties of any kind, whether express, implied, or statutory — including any implied warranties of merchantability, fitness for a particular purpose, accuracy, or non-infringement.

We do not warrant that the app will be uninterrupted, error-free, or that its predictions, forecasts, calculations, or recommendations will be accurate or produce any particular result.

Some jurisdictions do not allow the exclusion of implied warranties, so parts of this section may not apply to you. Nothing here limits any non-excludable consumer rights you have under your local law.

12. Limitation of liability

To the fullest extent permitted by law, we will not be liable for any indirect, incidental, special, consequential, or punitive damages, or for any loss of data, wasted imaging time, missed astronomical events, travel costs, or damage to equipment, arising from or related to your use of the app.

Our total aggregate liability for any claim relating to the app is limited to the greater of the amount you paid us for the app in the twelve months before the claim arose, or ten US dollars.

Nothing in these terms excludes or limits liability that cannot lawfully be excluded or limited, including liability for death or personal injury caused by negligence, or for fraud.

13. Apple-specific terms

The following apply because Night Logic is distributed through the App Store:

• This agreement is between you and us only, not with Apple. Apple is not responsible for the app or its content.
• Apple has no obligation to provide any maintenance or support for the app.
• If the app fails to conform to any applicable warranty, you may notify Apple, and Apple may refund the purchase price. To the maximum extent permitted by law, Apple has no other warranty obligation with respect to the app.
• Apple is not responsible for addressing any claim by you or a third party relating to the app, including product liability claims, claims that the app fails to conform to legal or regulatory requirements, and claims arising under consumer protection or similar legislation.
• Apple is not responsible for the investigation, defence, settlement, or discharge of any third-party claim that the app infringes intellectual property rights.
• You represent that you are not located in a country subject to a US Government embargo or designated as a “terrorist supporting” country, and that you are not on any US Government list of prohibited or restricted parties.
• Apple and its subsidiaries are third-party beneficiaries of these terms and may enforce them against you.

14. Changes to these terms

We may update these terms. The current version is always the one posted on this page, with the date shown at the top. Continuing to use the app after a change means you accept the updated terms; if you do not, stop using the app and, if you wish, cancel any subscription.

15. Contact

Questions about these terms, or about the app: wdutton04@gmail.com.