ASRU Astral Survey
Research Union

A closer look at a century of sky images

ASRU is an independent, volunteer-run research union. We build open machine-learning tools that find, measure and classify what is in astronomical images, from glass plates exposed in the 1880s to frames taken last night.

See our research Join ASRU

ASRU was formally founded on November 7, 2026, when its twelve members adopted the bylaws and elected the first Council at the Founding Assembly in Portland.

Read the assembly record

What we work on

Three programs, all run by volunteers. Every model, dataset and method note we publish is open.

Plate Archive Project

For about a century, observatories recorded the sky on glass. We train models to read digitized plates, sort real stars from flaws in the emulsion, and make old measurements easier to reuse.

Member Image Pipeline

A shared workflow that calibrates, plate-solves and checks images taken by members with their own telescopes.

Satellite Trails

trailmask, our open model for finding and masking satellite trails in wide-field images.
Observatory domes on the summit ridge of Maunakea under an orange and red sunset sky, above a layer of clouds.

Expeditions

Most of our work happens on weeknights in Portland and online. Twice in 2026 we traveled together to some of the darkest skies on Earth.

Sunset over the summit ridge of Maunakea, Hawaiʻi. Image: International Gemini Observatory/NOIRLab/NSF/AURA/J. Pollard, CC BY 4.0

News

All news

  1. ASRU is formally founded

    On November 7 all twelve members adopted the bylaws and elected the first Council. The Astral Survey Research Union now exists as a formal association.

  2. A first catalog of defects on digitized plates

    The Plate Archive Project has published its first labeled dataset, a trained classifier, and a technical note describing both.

  3. Founding Assembly set for November 7 in Portland

    The comment period on the bylaws has closed. All members are invited to vote on them and elect the first Council on November 7.

  4. Totality in Spain, then four nights on La Palma

    Five members watched the total solar eclipse of August 12 from near Soria and then spent four nights imaging under the protected skies of La Palma.

Join ASRU

Membership is free and open to anyone aged 18 or over, anywhere in the world. You do not need a telescope or a background in astronomy.

How to join

  • Review images

    Check what our models flag in plates and member frames, and correct them when they are wrong.

  • Write and review code

    Our pipelines are written in Python and run on donated compute.

  • Contribute observations

    Submit calibrated images from your own equipment to the member pipeline.

  • Help run the Union

    Writing, translation, events and membership all need volunteers.