Caelum

Caelum is an open-source, headless capture engine for all-sky cameras developed by AstroMeters. It is the primary software of the AMASC01 camera, designed for long-term unattended operation and scientific data collection.

Default software since October 2026. AMASC01 cameras sold from October 2026 onwards are shipped with Caelum pre-installed and pre-configured. Cameras sold earlier run the AllskyTeam/allsky stack and can be switched to Caelum on request – contact us if you need help.

Documentation: https://caelum.astrometers.eu
Getting started: https://caelum.astrometers.eu/guide/getting-started
Source code: https://github.com/roman-dvorak/caelum

Key Features

Sky-aware auto-exposure – Sun and Moon positions are computed from an offline ephemeris, and separate exposure and gain presets are used for day, civil, nautical and astronomical twilight, and night. See exposure control.
RAM-first image pipeline – frames are calibrated, measured and thumbnailed in memory; only what is worth keeping is written to disk, including raw FITS and DNG files with metadata.
Keograms and meteor detection – built-in plugins assemble a daily keogram and detect meteor streaks; third-party plugins use the same interface. See plugins.
Storage and remote archive – a rotating local cache with a retention policy and a self-healing rsync upload to a permanent remote archive, viewable as a static multi-camera gallery. See storage and upload.
Web UI – live view, recordings by night, file browser, settings, live logs and a web terminal, with admin and viewer accounts. See web UI.
Updates from the browser – releases are installed and rolled back from the web UI. See updates.

Operation

Connect the camera via Ethernet/PoE cable
Open the Caelum web interface using the camera’s IP address or hostname
Adjust capture, storage and upload settings if needed
Let it run – Caelum operates unattended day and night

Other Software Options

AMASC01 can also run AllskyTeam/allsky (the default software for cameras sold before October 2026) or indi-allsky.

Installation

Caelum comes pre-installed on new AMASC01 cameras. To install it on an older camera or another Raspberry Pi (Raspberry Pi OS Bookworm, 64-bit), run:

curl -fsSL https://github.com/roman-dvorak/caelum/releases/latest/download/install.sh | sudo bash

The installer sets up Caelum as a systemd service together with its web interface. Further options and manual installation are described in the Caelum deployment guide.