Use fixed obs time for NASA fetch and atmosphere check

Previous approach: scan a 3-day window, find best moon detection,
use that timestamp.  Problems: fuzzy composite (multi-day scan could
pick a frame far from actual full moon), no clear tie between the
NASA render and a specific observable moment.

New approach — MOON_OBS_TIME_LOCAL (default 22:30 local):
  On the night of the exact phase event, look at east frames in a
  ±MOON_OBS_WINDOW_MIN (default 30 min) window around the configured
  time.  The frame closest to that time determines atmosphere opacity;
  the same time (rounded to hour) drives the NASA Dial-a-Moon fetch.
  This gives one definitive moment per phase per month.

moon_phase_monthly.py:
  - PHASE_SPEC stripped to just post_delay + enabled_key (all window/
    illumination filtering removed — obs time is the only selector)
  - run_phase() replaced with obs-time logic; opacity derived from
    detect_moon quality on that single frame
  - MOON_FULL_POST_DELAY_DAYS / MOON_QUARTER_POST_DELAY_DAYS default
    changed to 1 (post morning after the phase, frames already on disk)

moon_composite.py:
  - atmosphere blur default: output_width//10 (192px) → output_width//20
    (96px) so cloud shapes survive the blur

sky-cam.conf:
  - MOON_OBS_TIME_LOCAL=22:30, MOON_OBS_WINDOW_MIN=30
  - Post delay defaults updated to 1

test_moon_composite.py:
  - Tries real NASA SVS Dial-a-Moon API first; procedural disc only as
    fallback if API unreachable
  - Runs detect_moon on the east frame to compute real opacity
  - Single output (test_composite_out.jpg)

https://claude.ai/code/session_01HkTxpNSTWtViZzxbrbKytR

sky-cam.conf

@@ -491,15 +491,28 @@ MOON_TRACK_FPS=12                  # output mp4 framerate
 MOON_TRACK_CRF=24                  # output mp4 CRF
 MOON_TRACK_RETENTION_DAYS=90       # delete tracker mp4s older than this; 0 = forever
 
-# Full-moon monthly tuning ────────────────────────────────────────────────────
-# How many days after the exact full moon to post.  3 = waits for D-1..D+2
-# nights to be on disk, then runs the morning of D+3.
-MOON_FULL_POST_DELAY_DAYS=3
+# Observation time ────────────────────────────────────────────────────────────
+# Local time used to select the east camera frame and the NASA Dial-a-Moon
+# render for each phase post.  The script looks at east frames within
+# ±MOON_OBS_WINDOW_MIN of this time on the night of the exact phase event,
+# picks the one closest to the target time, and uses it to:
+#   1. Determine atmospheric conditions (clear / hazy / overcast)
+#   2. Set the atmosphere overlay opacity on the NASA moon image
+#   3. Round to the nearest hour for the NASA API call
+#
+# 22:30 works well for full moon and first quarter (both visible after dark).
+# For third quarter (rises after midnight), consider 02:30 or leave at 22:30
+# and accept that the moon may be below the horizon — the script will warn
+# and post a clean NASA render instead.
+MOON_OBS_TIME_LOCAL=22:30
+MOON_OBS_WINDOW_MIN=30              # ±minutes around obs time to check east frames
 
-# Quarter (half-moon) tuning ──────────────────────────────────────────────────
-# 2 = waits for D-1, D, D+1 nights, runs the morning of D+2.
-MOON_QUARTER_POST_DELAY_DAYS=2
-MOON_QUARTER_MIN_ILLUMINATION=0.46 # ±4% of 50%: waxing/waning within 4% of exact quarter
+# Post delay ──────────────────────────────────────────────────────────────────
+# How many days after the exact phase to run the post.  The post delay gives
+# time for the obs-night frames to land on disk before the job runs.
+MOON_FULL_POST_DELAY_DAYS=1         # post the morning after the full moon
+MOON_QUARTER_POST_DELAY_DAYS=1      # post the morning after each quarter
+MOON_QUARTER_MIN_ILLUMINATION=0.46
 MOON_QUARTER_MAX_ILLUMINATION=0.54
 
 # Frame-acceptance thresholds — a candidate must beat all three to qualify.