Yaaawwn....
By using pages on this web site you agree to be a fine human being, to respect all sentient life and to not sue us or anyone maintaining the site for any reason. So there. We do the best we can for users and sponsors but no contract is formed when you use this website or sponsor any part of it. The part about no contract formed is especially important, now that Attilla has died and the site is in transition. Please also note that if you have requested a chart, all the information about your request will be available to all the maintainers: we can't maintain it without the request information, even though when you made your original request, Attilla thought only he'd ever see the request. You may of course, request that the executor (and current sole maintainer of the site), remove all information associated with your chart request... including the chart. Such requests must be received by 2026-06-30. The next bit was funnier before this stuff got inserted.
After all, it's just a weather forecast. In particular we make no statements about the safety of any site for which we provide a weather forecast. (Most of them we've never been to.) Not all clear sky chart locations are public or even physical observings sites. Check with the land owner, local astronomy clubs, or even local law enforcement for physical and safety concerns before attempting to visit sites listed on cleardarksky.com.
Clear Sky Charts and all the data on clear dark sky are free to use for everyone through web browsers. But authors of mobile device apps must write the maintainers of the site for permission before using the data.
We get to change the terms of use, or any policy without telling anyone first. And this will keep changing. You don't have to use this, if you have a problem with that.
All clear sky charts belonged to Attilla Danko and now the team of clear sky chart maintainers, even if we use casual phrases like "your chart". They're ours. Or as Attilla said, "Mine I say! ...all MINE!..BWAA HA HA HA........"
We reserve the right to delete charts that we believe have fallen into disuse. For the moment, that means charts whose legend pages haven't been used in 30 days.
If you sponsor the clear sky charts, we will hold you in highest esteem and thank you, but no contract is formed for service.
Websites which do not charge admission may link any page at cleardarksky.com.
Websites which don't charge admission, and also don't make revenue from advertising, may display chart images, or preview images, provided each image links the legend page for that chart. Use the sample html that we have provided at the bottom of each chart's legend page. (Sorry, the current maintainers aren't as funny as Attilla was: we don't know what to swap in for the jokes we had to delete.)
Do not copy text, source-html or scripts from any page unless you get written permission from us. (Mostly because it just will not work off the webhost.)
All pages on cleardarksky.com plus all clear sky chart images and preview images, no matter what website they appear on, are Copyright © 2026 by Ingrid G. de Buda, as sole beneficiary of Attilla Danko's estate.
Any transparency, cloud or seeing forecast map, labeled "CMC" is provided by the Canadian Meteorological Center and is © Crown copyright, product of Environment Canada. Seek their permission to display any of their weather maps, even if the maps are sourced from cleardarksky.com
All light pollution maps are from the Light Pollution Atlas 2022 by David Lorenz. David recalculated the The World Atlas of the Artificial Night Sky Brightness with newer data. Contact David to re-publish his light pollution maps even if you get them from cleardarksky.com.
The ECMWF forecast on clear sky charts is from the Norwegian Meteorological Institute, also known as MET Norway.
If you email us, we will only email you with regard to this web site or possibly personal correspondance.
We do not email sponsors to bug them for ever increasing amounts of money (unless they ask me to remind them of expiring sponsorships). We might email sponsors once more about a previous sponsorship. This is subject to change, as maintenance transfers to a new team.
We may copy you on an email to a third person if that person is asking for changes to a chart that you requested.
But we've asked google to count page usage with Google Analytics which may set their own cookies. We use Google Analytics to figure out when to buy more computers, in what order to update charts (we update the sponsored and most-used ones first) and to identify charts that are no longer used. We might also use Google AdSense, which may set their own cookies, to display ads. But we never display ads on sponsored clear sky chart pages.
You can set your browser to reject google's cookies, if you like. We consider your usage of cleardarksky.com as acceptance of such cookies otherwise.
Chart requesters of observatories who do not want their site made quite so public, for security reasons, may ask for location confidentiality. We will then do our best to make sure their latitude and longitude does not appear on cleardarksky.com. We also won't show distances to private charts as any less than 24km (15mi). We will turn off the road map, satellite prediction and other nifty, but potentially location-revealing, links on the chart's legend page. We will also turn off the "on click" navigation features of the light pollution and forecast maps linked to the chart's legend page.
A better option might be to pick the middle of a nearby park or lake. If it's within 10km, the forecast will be the same, your location isn't revealed and you don't lose any features.
Under Canadian tax rules, this is not a charitable organization and so cannot offer charitable tax receipts.
(begin Attilla's tax rant) Actually, I pay Canadian income tax on all sponsorships even if sponsors think they are giving me gifts. All payments also include HST/GST from sponsorships from Canadians. Sponsorships from people outside of Canada, and are not GST registered, are "zero-rated" for GST. (If you don't know what that means, I envy you.) I consider all sponsorships to be all-taxes included so sponsors need not worry about it. (end Attilla's tax rant). (Begin Ingrid's tax rant) Since I was the one actually doing the paperwork for the taxes at year-end, I immediately STOPPED all sponsorship to save myself the headache. As the site transitions to new owners it would be kind if all the former sponsors could show their support and sponsor the new maintainers. (End Ingrid's tax rant). This will change when the site transitions to American maintainers.
Attilla prefered sponsorships. Sponsors are wonderful people. But there weren't enough of them. So he put ads on some pages on cleardarksky.com. He did not place ads on clear sky chart pages that are sponsored. Ingrid tried hard to find all the bits of code that had ads, and remove them. The new maintainers currently don't plan on general ads.
Ads that are streamed to the pages are from Google Adsense. Info about how Google uses data it collect from displayed ads is here.
We do not host guest posts. Stop emailing us.