Set space imagery as your desktop wallpaper, with NASA APOD and nine other sources. Native Swift on macOS; Electron on Windows and Linux.
Loading today's Astronomy Picture of the Day…
Click the star in your menu bar and a panel of frosted black glass floats over your desktop. Today's image fills the hero; the interface quietly re-tints to wear its colours. One tap sets it as your wallpaper.
Every day, Caelum fetches NASA's Astronomy Picture of the Day and sets it as your wallpaper - automatically, in the background.
APOD is the star - joined by ESA/Hubble, James Webb, ESO, NASA EPIC and themed 4K collections: Earth from Space, Solar System, Space Stations and Interstellar (black holes & wormholes).
Caelum prefetches the newest images in the background, so switching is instant - and reads each image's true pixel size to badge it 4K, HD or SD.
Open Caelum from the menu bar on macOS or the system tray on Windows and Linux. Linux window behaviour depends on the desktop environment.
Caelum extracts the dominant colour of each image and tints its accents to match - every image gives the app a new mood.
No accounts, no tracking, no analytics. Images come straight from public APIs. The whole thing is MIT-licensed on GitHub.
Switch sources from the strip inside the panel. Everything works out of the box - no API keys required.
Grab the latest Caelum.zip from GitHub Releases and unzip it into /Applications.
Caelum is free and open source, so it isn't notarized. On first launch, right-click the app and choose Open to get past Gatekeeper.
Look for the orbit glyph in your menu bar. Click it, pick a source, and you're flying.