DESIGN.md@benchmarks/visual/night-shift git:20261010.9696da4A

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# Night Shift Direction

## Chosen direction

Treat the page as a quiet night field guide: two image records are the instrument, and the interface behaves like a page marker between scales. The wide DSS2 field establishes context; the Hubble ACS observation resolves the encounter. The first screen is dark enough for the material to remain visible, but the type is clear and restrained rather than a generic neon space dashboard.

## Alternatives

- A dense observatory dashboard: useful for repeated measurement, but it makes a single astronomical image feel like a data tile.
- A cinematic full-screen space poster: memorable, but it hides the actual reading task and source trail.
- A field guide with two source scales: chosen. It makes the wide field and Hubble detail materially distinct while keeping the same M51 encounter, facts, controls, and provenance visible.

## Material decisions

- `m51-galaxy.jpg` supplies the wide DSS2 field and `m51-hubble.jpg` supplies the Hubble ACS pair/core view. Each image keeps its own record and credit.
- Sora handles navigation and measurements; Newsreader handles the field note.
- Paper, ink, blue, and coral are derived from the inspected Hubble image rather than a purple space gradient.
- Grouping uses open image stages, spacing, tone, and named feature markers. Repeated cards, decorative star fields, and fake telemetry are rejected.
- The view transition has a purpose: it changes the scale and material of the observation. Reduced motion keeps the final view and controls usable.

## Source and rights

The local wide-field image is the 7095x6219 DSS2 reproduction recorded in `../shared/assets/m51-source.json`; its official page identifies ESA/Hubble and Digitized Sky Survey 2. The local close image is a 6000x4164 rendition of the Hubble ACS observation heic0506a, recorded in `../shared/assets/m51-hubble-source.json`. The page keeps the full applicable credits beside the relevant records and links the ESA/Hubble reuse policy.