Enjoying Astrometric? It's free, with no ads or accounts. If it helps you catch a clear night, you can chip in toward its upkeep.
Donate with PayPalClouds matter most; transparency comes from humidity, seeing from the 250 hPa jet stream, wind from ground gusts, and darkness from twilight and the moon. Forecast from Open-Meteo (CC BY 4.0); Kp from NOAA SWPC; light pollution from NASA VIIRS night lights; satellite imagery from NASA GIBS and EUMETSAT; target photos from the Digitized Sky Survey 2 (STScI/AURA, Palomar/Caltech, UK Schmidt), bundled for popular targets and fetched from CDS hips2fits or NASA SkyView for the rest. NGC and IC catalogue: OpenNGC by Mattia Verga (CC BY-SA 4.0); Sharpless and Barnard catalogues via VizieR (CDS); constellation lines from d3-celestial (BSD-3); borders from Natural Earth. Sun, moon and planet positions are calculated in your browser. Saved sites and settings stay on this device.