ASRU Astral Survey
Research Union

Member Image Pipeline

One shared, documented route from a member’s raw frames to calibrated, solved and checked images.

Amateur astronomers setting up for an evening of observing. Image: Annatsach / Wikimedia Commons, CC BY 4.0

The problem

Our members take images with very different equipment: camera lenses on tripods, small refractors on tracking mounts, cooled astronomy cameras. Each of us used to process images in our own way, which made it hard to compare results or reuse each other’s data.

The member image pipeline gives everyone the same route. It is deliberately conservative: it calibrates and measures, but it does not make images prettier.

How a submission is processed

  1. Checks. File formats, exposure times and header information are checked, and problems are flagged.
  2. Calibration. Bias, dark and flat frames are combined and applied.
  3. Plate solving. Each frame is matched to star catalogs to find exactly where on the sky it points.
  4. Trail masking. Satellite trails are found with trailmask and masked.
  5. Measurement. Sources are extracted and matched against Gaia, and a photometric zero point is fitted.
  6. Report. The member receives quality figures for every frame: star size, elongation, background level and how many stars were matched.

The method is described in ASRU-TN-2026-001.

Three people in silhouette around a large amateur telescope on a mount under a starry sky.
Amateur astronomers at the Grand Canyon Star Party. Image: Grand Canyon National Park Service, public domain

What the data is used for

Processed frames are used to train and test our models, including trailmask. Members can also use their own reports to improve their technique. Frames from our 2026 expeditions to Hawaiʻi and La Palma are part of the test sets.

Your images stay yours

Members keep the copyright in every image they submit. By submitting, a member allows ASRU to process the image and to publish measurements and small cutouts derived from it. Full images are only published with the member’s permission. See privacy and data.

Submitting images

Submission is open to ASRU members. The guide for members covers file naming, calibration frames and the most common reasons a frame fails. If you are not a member yet, see how to join.