Terms of use

Dark Window is a planning aid for astrophotography. It combines weather forecasts and astronomy calculations into a GO / NO-GO verdict, target ideas and calculators. The planner and guides are free. Premium adds alerts, your own scoring rules, more saved sites, gear and targets, and the multi-site planner.

Weather forecasts are often wrong, especially a few days out. A GO verdict does not promise clear skies, and a NO-GO does not promise cloud. Use your own judgement before travelling, setting up equipment or leaving it outdoors. The site and its alerts are provided as they are, without warranty, and we are not responsible for lost nights, travel costs or equipment damage.

• Premium costs $3 a month or $24 a year, in US dollars, plus any tax that applies.
• It renews automatically each month or year until you cancel. Payments are taken by Stripe.
• You can cancel at any time from the Premium page. Access continues to the end of the period you paid for.
• Refunds are covered on the refunds and cancellation page.
• We may change prices for future periods. We will tell you before a change takes effect, and you can cancel before it does.

A licence key is for you. Do not post it or share it so others can use Premium for free. We may switch off a key that is being shared or was obtained by misusing a payment or access code.

Do not try to break, overload or scrape the site, bypass Premium limits, or use it for anything unlawful. The data the site shows comes from third-party sources, and we may limit requests to keep the service available.

We may add, change or remove features, and we may stop the service. If we end Premium entirely we will refund the unused part of any prepaid period.

To the extent the law allows, our total liability for any claim about the site is limited to the amount you paid for Premium in the 12 months before the claim. Nothing here limits rights you have by law that cannot be limited.

Questions about these terms can go to the contact address for Dark Window.