OriginStack 2.17.0

Which download?

You have	Download
Windows, want it installed	OriginStack-2.17.0-setup.exe
Windows, no install (one file)	OriginStack-2.17.0-windows-x64-portable.exe
Windows, no install (folder)	OriginStack-2.17.0-windows-x64.zip
Mac with Apple silicon (M1 or later)	OriginStack-2.17.0-macos-arm64.zip
Mac with Intel	OriginStack-2.17.0-macos-x86_64.zip
Linux	OriginStack-2.17.0-linux-x64.tar.gz

Comets stacked on the comet automatically, more of the frame kept, cleaner multi-night
edges, true colour through a nebula filter, and sharper drizzle.

Added

• Comets are stacked on the comet automatically. When the target is a comet (the FITS
  OBJECT, the session name or the folder is a designation such as C/2025 R2 (SWAN),
  12P/Pons-Brooks or 3I/ATLAS), the automatic settings turn on --comet-mode: besides the
  usual star-aligned stack you get <stem>_comet.fits, aligned on the nucleus, and
  <stem>_comet_blended.fits, sharp comet on sharp stars. Before, a comet session came out as
  a star stack with the comet smeared along its track. --no-comet-mode turns it off.
  The comet is located with its JPL Horizons ephemeris (three requests per run; not with
  --offline): on 3I/ATLAS the motion search alone had locked onto a passing satellite.

Changed

• Multi-night combines lose their ragged edges. Nights shot at different field rotations
  only partly overlap, and the combined image kept the reference night's whole frame: wedges
  and rims covered by one or two nights, at a different depth and colour (rainbow edges and
  corner wedges on a nine-night Whirlpool). The combined stack (and --merge) is now cut to the
  largest rectangle that at least half of the nights' total weight covers; on that Whirlpool,
  96% of the frame. The WCS moves with the crop.

• --stream gets the same treatment as a normal stack. Its output kept the whole sensor
  frame, with thin rims made of the one or two frames that drifted over them (a dark strip and
  a dashed bottom row on M66); it is now cut to the area at least half the frames cover. And
  the automatic settings never chose the learned deconvolver in stream mode (the camera was
  not identified there), so streamed stacks were processed with the older wavelet chain.

• Nebula-filter sessions keep their colour. Under the Origin's Nebula filter slot (an OIII,
  dual-band or other narrowband filter), the automatic settings no longer apply SCNR, which
  removes green -- where OIII lands -- or the gray-locus colour calibration, which assumes
  neutral stars and scaled up noise in the near-empty red channel. On an OIII Lagoon the nebula
  comes out brighter, with more of its faint structure, in its own teal-green.

• "Large shifts detected" only when they are large for the frame (over 10% of its shorter
  side). It used a fixed 20 px and appeared on nearly every session from 2026 firmware, whose
  drift and dithering move the field 40-150 px -- which registration handles.

• The stack keeps more of the frame (--full-field, now on by default). The edges that
  dithering, drift or field rotation leave uncovered by some frames used to be cropped off;
  they are now kept wherever at least half the frames cover them, combined from those frames,
  with a little more noise at the very edge (<output>_coverage.fits maps the frame count).
  On a drifting Fireworks Galaxy session: 2996x1986 -> 3017x2024 px, about 19 s more.
  --no-full-field restores the old crop. Skipped quietly with drizzle, comet mode, elastic
  registration and the uncertainty map.

Fixed

• --comet-designation used the wrong time. The Origin stamps DATE-OBS in local time
  with the offset in TIMEZONE; the ephemeris was asked for that time as UTC, eight hours
  out (3I/ATLAS predicted 0.38 deg from where the telescope pointed). It also made one Horizons
  request per frame and then used the positions only for a trailing warning; the predicted
  track now steers the nucleus search.

• The AAVSO report closed its lightcurve file late, which could keep it locked on Windows.

• --config KEY=VALUE now works, as the 2.15 and 2.16 notes already said it did (for
  example --config nn_deconv_blend=0.5 or --config preview_black_sigma=1.0). --config
  took only a file, so such a setting was read as the name of a missing file and silently
  ignored; with --from-stack it also kept the earlier run's saved settings from loading,
  so the re-run used defaults. --config can be repeated; a KEY=VALUE setting wins over
  the config file and over the automatic settings.

• Sharper drizzled stacks (--drizzle-scale 2). The automatic settings switched drizzle to
  the soft Magic Kernel to avoid ringing around bright stars; on two Origin sessions that made
  stars about 10% wider than the normal stack, with no less ringing than the default Lanczos-3
  kernel. Drizzle now keeps Lanczos-3: stars as narrow as the normal stack, with 9-22% less noise
  when viewed at the same scale. --drizzle-kernel magic still selects the soft kernel.