Sources and licences

ReconStar labels source age and confidence separately from its opportunity score. Third-party names identify data sources and do not imply endorsement.

Astronomy Engine

Sun, twilight, moon, planet and eclipse calculations run on-device using Astronomy Engine 2.1.19 under the MIT licence. The app displays calculated results rather than asking a remote astronomy service.

Astronomy Engine project and licence

GeoNames

The offline city search contains a generated 12,000-city subset of the GeoNames cities15000 snapshot retrieved on 14 July 2026. GeoNames data is provided under CC BY 4.0.

Attribution: GeoNames geographical database.

Apple / Google platform location services

In the installed iOS and Android apps, a postcode or address is passed to the phone's platform geocoder only after the user taps Find. Apple or Google may process the search text under their own privacy terms. ReconStar does not send the search text to its connected service. The exact returned point is stored locally only after the user confirms it; GeoNames supplies nearby region and time-zone context offline.

Apple Maps privacy · Google privacy policy

International Meteor Organization

The bundled major-shower catalogue is derived from the International Meteor Organization working calendar. Shower dates and rates are planning approximations and may change between yearly calendars.

International Meteor Organization meteor-shower calendar

MET Norway Locationforecast

When connected weather is available, ReconStar uses MET Norway Locationforecast 2.0. The service receives coordinates for the requested coarse-area centre, identifies the ReconStar application and follows the provider's caching requirements.

Attribution: Data from MET Norway, modified and interpreted by ReconStar. Locationforecast is licensed under CC BY 4.0 and subject to the MET Norway licence notice and API terms of service.

NOAA Space Weather Prediction Center

ReconStar uses NOAA SWPC OVATION data as model intensity — not as a literal probability that a person will see aurora — and uses planetary Kp as geomagnetic context. The app shows issue times and stale/error states when available.

Aurora 30-minute forecast · Planetary K-index · US National Weather Service disclaimer

NASA Earthdata GIBS · VIIRS Black Marble

NASA Earthdata GIBS supplies the VIIRS Black Marble image dated 31 December 2016 used as a historical night-light reference layer for a coarsened area. It is not live light-pollution monitoring, a Bortle-class measurement or part of the opportunity score. The separate Worldview link opens NASA's own interactive map.

NASA Global Imagery Browse Services · NASA Worldview

Method, freshness and limits

Current-condition cards include source update or retrieval time and can be marked stale or unavailable. If a provider fails, ReconStar falls back to on-device astronomy rather than presenting old condition data as current. Connected weather is never presented beyond the provider's actual forecast horizon; later planning dates are labelled astronomy-only.

ReconStar combines on-device astronomy calculations with recognised weather, space-weather and satellite-derived data. Forecasts and scores are estimates and conditions can change. Check official weather, safety and access guidance. Never view the Sun without certified solar-viewing equipment. ReconStar is independently developed and is not endorsed by Astronomy Engine, GeoNames, the International Meteor Organization, MET Norway, NOAA, NASA, Cloudflare, Expo, Apple or Google.