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February 14: Chasing NASA's Image Quality

A marathon session: 33 pull requests merged (8 features, 10 fixes, 1 docs, 2 maintenance, 12 dependency updates). Major work on the composite imaging pipeline.

Developer Journal

Late night session — started past midnight and friends had to tell me to sleep. The composite wizard is getting more user friendly, and the results are visibly better, but the gap between what the app produces and what NASA publishes is humbling. Shared side-by-side screenshots with friends: still room for improvement. The color mapping is slightly off and missing an entire channel (luminance in LRGB).

App-generated composite of the Southern Ring Nebula in pink and red tones

NASA published JWST image of NGC 3132 Southern Ring Nebula for comparison

Wikipedia reference showing NGC 3132 in near- and mid-infrared light

A friend with signal processing background jumped in with suggestions — harmonic mean instead of standard mean for compositing, edge detection convolutions for weighted pixel functions, frequency weight matrices. The kind of domain knowledge that language models can't replicate because they'd be penalized for the speculative ideation needed. Another friend shared a PDF of an image processing textbook — immediately fed it to Claude to learn from.

Photo of Image Operators - Image Processing in Python by Jason M. Kinser

Discovered that STScI already serves JWST public data from S3 (s3://stpubdata/). This changes the deployment calculus — bucket-to-bucket transfers instead of slow HTTP chunking through the MAST portal API. A friend suggested self-hosting to get started, but AWS is the more realistic path.

Had Claude do deep research on how to get from the current composite output to NASA's published version. There's an epic across 5 features to close that gap.

Terminal explanation of the edge artifact problem when combining with mean

Terminal showing root cause in mosaic_engine.py with NaN masking fix

Grayscale FITS mosaic showing visible sensor edge artifacts as dark bands

Docker Desktop showing running containers for main and agent Docker stacks

Highlights

#361 add N-channel composite API endpoint with color mapping

Adds POST /composite/generate-nchannel endpoint (B3.2) that accepts N channels with hue or explicit RGB color assignments, enabling multi-filter JWST composites with 4-6+ filters.

The existing /composite/generate endpoint is hardcoded to 3 channels (R/G/B). NASA JWST composites typically use 4-6 filters. This endpoint uses the B3.1 color mapping engine to support arbitrary fi...

#360 add N-channel color mapping engine for multi-filter composites

Adds the core B3.1 N-channel color mapping engine — pure Python functions and Pydantic models that map N JWST filters to RGB via hue-based color assignment. This is the foundation that B3.2 (API) and B3.3 (UI) will build on.

The current composite pipeline is hardcoded to 3 channels (R/G/B). NASA JWST composites typically use 4-6 filters mapped to distinct colors. This engine enables that by providing hue→RGB conversion, w...

What Changed

Features (8)

  • #324 add server-side reprojection cache for composite previews
  • #325 drag-and-drop channel assignment with thumbnails for composite wizard
  • #328 mosaic wizard UI refresh with 2-step flow and thumbnail cards
  • #329 normalize MAST target search variants
  • #330 multi-agent Docker stack infrastructure
  • #356 add background neutralization for RGB composite wizard
  • #360 add N-channel color mapping engine for multi-filter composites
  • #361 add N-channel composite API endpoint with color mapping

Bug Fixes (10)

  • #318 use memory-efficient loading for thumbnail generation
  • #322 show metadata for mosaic-generated FITS files in ImageViewer
  • #346 agent-stack.sh bugs and review.sh improvements
  • #349 add 127.0.0.1 to CORS allowed origins
  • #350 improve mosaic wizard footer UX — primary action is now Generate Mosaic
  • #351 collapsible footprint preview and mask sensor edge zeros in mosaic
  • #352 replace instrument filter with wavelength filter, fix mosaic viewer and thumbnails
  • #353 trim leading/trailing spaces from search input
  • #354 include target name in dashboard search filtering
  • #358 resolve SA1204 static member ordering warning

Documentation (1)

  • #359 add B3 multi-channel composite epic to development plan

Maintenance (2)

  • #320 fix markdown table alignment across project docs
  • #321 add language specifiers to fenced code blocks

Dependencies (12 updates: @typescript-eslint/eslint-plugin, @vitejs/plugin-react, Microsoft.AspNetCore.Authentication.JwtBearer, Microsoft.AspNetCore.OpenApi, Microsoft.CodeAnalysis.NetAnalyzers, Swashbuckle.AspNetCore, actions/upload-artifact, aiohttp and 4 more)

Issues

Opened:

  • #319 — fix: MAST Sync bulk import duplicate key error (500)
  • #326 — [Feature] Improve target search for name variants (Crab Nebula / NGC 3132 / NGC-3132)
  • #347 — chore: migrate eslint 9 → 10
  • #348 — chore: migrate pytest-asyncio 0.23 → 1.x
  • #357 — Refine RGB composite default stretch and background neutralization

Closed:

  • #288 — Composite Preview Performance — Architecture Rework
  • #301 — fix: ImageViewer shows no metadata for mosaic-generated FITS files
  • #317 — Thumbnail generation fails for large FITS files (413 Request Entity Too Large)
  • #319 — fix: MAST Sync bulk import duplicate key error (500)
  • #326 — [Feature] Improve target search for name variants (Crab Nebula / NGC 3132 / NGC-3132)

30 commits across 33 pull requests. Next: February 15, 2026 — add F1 S3 direct access epic to development plan, increase default FITS file size limit from 2GB to ..., increase default FITS array element limit from 100...