Batch processing on the command line

Goal: stack a whole session, or many captures, without opening the app.

Every helia stack run needs only an input and an output. Helia reads the filter from each file name, so with names such as Sun_Ha_001.ser and Sun_CaK_002.ser one command suits both and each gets its own recommended settings.

A folder of captures

In a POSIX shell (Linux, macOS, or Git Bash on Windows):

mkdir -p stacks
for f in captures/*.ser; do
  helia stack "$f" -o "stacks/$(basename "$f" .ser).tif" --sharpen wavelet --quiet \
    || echo "failed: $f"
done

In PowerShell:

New-Item -ItemType Directory -Force stacks | Out-Null
Get-ChildItem captures\*.ser | ForEach-Object {
  helia stack $_.FullName -o "stacks\$($_.BaseName).tif" --sharpen wavelet --quiet
  if ($LASTEXITCODE -ne 0) { Write-Warning "failed: $($_.Name)" }
}

Both carry on after a failing capture, so one bad file does not hide the others. --quiet hides the progress bar and the summary; the exit status is non-zero on failure. Leave --quiet off to keep each run's summary in a log:

helia stack "$f" -o "stacks/$(basename "$f" .ser).tif" > "logs/$(basename "$f" .ser).txt" 2>&1

Test the batch on one file first

helia info captures/Sun_Ha_001.ser     # what Helia will use, and any notice
helia stack captures/Sun_Ha_001.ser -o test.tif --sharpen wavelet

Other formats and options

• A PNG for sharing and a FITS for measurement from the same capture: run it twice, with -o x.png --preset ha and -o x.fits.
• All sharpening, colour and alignment options work in a batch; see the CLI reference.
• Make the same edits to existing images with helia edit, with a saved preset:

for f in stacks/*.tif; do
  helia edit "$f" -o "edited/$(basename "$f")" --edits "H-alpha gentle" --quiet
done

One at a time, or all at once

The GPU is one device, so running several helia stack jobs at once rarely helps. Run them in turn, as above. If you want a queue that other programs can add to, use the API, which runs one job at a time by default.