# Azimuth protection

Obs.Control ends Telescope settings with Filter flats. Weather Settings ends
with Azimuth protection, shared by the telescopes belonging to that WeatherSentinel.

Each of the three polar maps contains 90 independent 4-degree slices. North is
0 degrees and azimuth increases clockwise through east at 90 degrees. A slice
covers every altitude. Select a colour and paint with a click, drag, or keyboard
Enter/Space. Fill-map, copy-previous-map, and reset controls edit the draft;
Save azimuth protection applies it.

The maps apply from observing begins to time A, from A to B, and from B to
observing ends. Defaults are 22:30 and 02:30 in the observatory's civil timezone,
including daylight-saving changes. Times after midnight belong to the same
observing night. B follows A within the existing local-noon-to-noon night;
equal times are allowed and give an empty middle era. No duration or exposure
quality threshold is added.

| Colour | FIFO | Calendar |
| --- | --- | --- |
| Red | Ineligible if any part of the track enters it | Block the track, including accepted-warning submissions |
| Orange | Ineligible if any part of the track enters it | Warn about stray light and require explicit risk acceptance |
| Blue | Rank after every eligible green track | Warn and require explicit risk acceptance |
| Green | Normal scheduling | No azimuth warning |

Blue does not impose a minimum queue size or delay: a blue request remains
eligible when no green request can run. Existing telescope-scope, funding,
Moon, and FIFO ordering apply within each colour tier. All calendar durations
can accept orange/blue risk, including long exoplanet events.

Calendar writes assess every defined project/sequence target over the full
booking, with moving-target positions evaluated at assessment time. Checks run
on creation and modification, including frontend copies, drags, resizes, and
night-window correction retries. Risk acceptance is tied to the site, maps,
target definitions, and booking times. It is recorded with a server timestamp.
Red never offers an override. Automated transit submission reports a refusal
when the event would need risk acceptance; users can book it explicitly.
Undefined target positions are recorded as unassessed diagnostics rather than
inventing a new booking prerequisite. Real-time reservations without a target
have no predicted track; OBS applies red checks when pointing is requested.

The track evaluator includes minute anchors, exact era changes, and adaptive
refinement across sector boundaries, north wrap, and azimuth turns. Numerical
resolution is one millisecond; it is not a fit/quality rejection threshold.
OBS also refuses commanded red pointings and reports orange/blue project warnings.

## Shared data and deployment

`wema_settings.azimuth_protection` contains `time_a`, `time_b`, and `periods`
(three arrays of 90 colour names). Missing settings are independent green maps.
The save command is `set_azimuth_protection`. Hub owns the saved settings and
does not let stale WEMA telemetry overwrite them. WEMA applies the same schema
and supports the command through its local console.

Hub includes the maps and `azimuth_protection_timezone` in existing enclosure
snapshots. OBS retains those fields and forwards them in FIFO polling. Arbiter
assesses the complete estimated observation, rejects red/orange tracks, and
includes diagnostics on rejected candidates and selected blue work. Its exact
top-k pruning uses a green lower bound so it cannot discard a later green
candidate in favour of an earlier blue one. Active time-dependent maps require
a valid observatory timezone to evaluate their eras.

Keep `azimuth_protection.py` identical in Hub, CodexOBS, CodexWEMA, and Arbiter.
Deploy Hub and Arbiter before updated OBS, then WEMA. Hub's enclosure projection
provides authoritative maps even before WEMA is updated. Older OBS versions do
not forward maps or enforce red pointings, so all affected OBS clients need the
update before relying on protection. Local tests and browser fixtures do not
establish deployed-worker or hardware behavior.