Terms and conditions

Copyrights and credits

Data usage

When you use airmass.org, various items of data are recorded by the server. These logs are discarded after one week. By inspecting the server logs, I can see the details of the observability charts that have been generated - the object name and coordinates, the location of the observer, the date and time. I use these data to improve the website - for example, I add new observatory locations when user-defined locations or geolocated positions suggest that they might be useful. Most data does not show up in the server logs as charts are generated by client-side javascript after the initial page load, but I occasionally track this too for site improvement purposes.

Some user preferences and links to the last 100 charts you have plotted are stored by your browser. If you enable geolocation, the location data provided by your browser is sent to google maps and openweathermap.org to display the location and fetch the weather forecast. If you share any links, please be aware that the geolocated position will be visible in the URL.


While the calculations and plots produced by the site are intended to be useful and reliable, they come with no guarantee of any kind. All risk arising from the use of this website and the data it provides is borne by the user. If you find any errors in the calculations, or wish to contact me for any other reason about airmass.org, please get in touch at rw@nebulousresearch.org.