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Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for HD 189733: 05-21 (96), 05-19 (95), 05-20 (95), 05-22 (95), 05-17 (94) — by astronomy; check the weather when the night is within four days.
2029-05-04astronomy score per night — click a bar for that night2029-06-02
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2029-05-04 Fri 54 — unknown 01:30–04:25 (good, 2.92 h) 71.1° 06:30 6.17 55% 39.4°
2029-05-05 Sat 62 — unknown 01:25–04:25 (good, 3.0 h) 71.1° 06:25 6.12 45% 40.2°
2029-05-06 Sun 68 — unknown 01:20–04:20 (good, 3.0 h) 71.1° 06:20 6.06 35% 43.9°
2029-05-07 Mon 74 — unknown 01:15–04:20 (good, 3.08 h) 71.1° 06:20 6.0 26% 49.8°
2029-05-08 Tue 80 — unknown 01:15–04:20 (good, 3.08 h) 71.1° 06:15 5.95 19% 57.1°
2029-05-09 Wed 84 — unknown 01:10–04:15 (good, 3.08 h) 71.1° 06:10 5.89 12% 65.2°
2029-05-10 Thu 85 — unknown 01:05–04:15 (good, 3.17 h) 71.1° 06:05 5.83 6% 73.9°
2029-05-11 Fri 87 — unknown 01:00–04:15 (good, 3.25 h) 71.1° 06:00 5.78 3% 83.0°
2029-05-12 Sat 88 — unknown 00:55–04:10 (good, 3.25 h) 71.1° 06:00 5.72 0% 92.2°
2029-05-13 Sun 90 — unknown 00:55–04:10 (good, 3.25 h) 71.1° 05:55 5.67 0% 101.5°
2029-05-14 Mon 91 — unknown 00:50–04:10 (good, 3.33 h) 71.1° 05:50 5.62 2% 110.7°
2029-05-15 Tue 90 — unknown 00:45–04:05 (good, 3.33 h) 71.1° 05:45 5.56 5% 119.6°
2029-05-16 Wed 92 — unknown 00:40–04:05 (good, 3.42 h) 71.1° 05:45 5.51 11% 127.7°
2029-05-17 Thu 94 — unknown 00:40–04:05 (good, 3.42 h) 71.1° 05:40 5.46 18% 134.6°
2029-05-18 Fri 94 — unknown 00:35–04:00 (good, 3.42 h) 71.1° 05:35 5.41 26% 139.3°
2029-05-19 Sat 95 — unknown 00:30–04:00 (good, 3.5 h) 71.1° 05:30 5.36 36% 140.8°
2029-05-20 Sun 95 — unknown 00:30–04:00 (good, 3.5 h) 71.1° 05:25 5.31 47% 138.6°
2029-05-21 Mon 96 — unknown 00:25–04:00 (good, 3.58 h) 71.1° 05:25 5.26 58% 132.9°
2029-05-22 Tue 95 — unknown 00:25–03:55 (good, 3.5 h) 71.1° 05:20 5.21 70% 124.7°
2029-05-23 Wed 93 — unknown 00:25–03:55 (good, 3.5 h) 71.1° 05:15 5.16 80% 114.8°
2029-05-24 Thu 88 — unknown 00:30–03:55 (good, 3.42 h) 71.1° 05:10 5.11 88% 103.8°
2029-05-25 Fri 67 — unknown 00:30–03:55 (good, 3.42 h) 71.1° 05:05 5.07 95% 92.4°
2029-05-26 Sat 55 — unknown 01:20–03:50 (good, 2.5 h) 71.1° 05:05 5.03 99% 80.9°
2029-05-27 Sun 46 — unknown 02:15–03:50 (good, 1.58 h) 71.1° 05:00 4.98 100% 69.7°
2029-05-28 Mon 39 — unknown 03:20–03:50 (good, 0.5 h) 71.1° 04:55 4.94 98% 59.4°
2029-05-29 Tue 36 — unknown 23:30–03:50 (marginal, 4.33 h) 71.1° 04:50 4.9 94% 50.4°
2029-05-30 Wed 37 — unknown 23:20–03:45 (marginal, 4.42 h) 71.1° 04:50 4.86 88% 43.6°
2029-05-31 Thu 60 — unknown 23:40–00:15 (good, 0.58 h) 71.1° 04:45 4.82 80% 39.7°
2029-06-01 Fri 71 — unknown 23:40–03:45 (good, 4.08 h) 71.1° 04:40 4.79 70% 39.4°
2029-06-02 Sat 81 — unknown 23:35–03:45 (good, 4.17 h) 71.1° 04:35 4.75 61% 42.3°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-05-04&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.