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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 Triangulum Pinwheel: 02-21 (44), 02-22 (41), 02-23 (40), 02-24 (38), 02-25 (37) — by astronomy; check the weather when the night is within four days.
2041-02-21astronomy score per night — click a bar for that night2041-03-22
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2041-02-21 Thu 44 — unknown 19:35–21:20 (good, 1.75 h) 79.2° 15:50 9.98 71% 159.1°
2041-02-22 Fri 41 — unknown 19:40–21:20 (good, 1.67 h) 79.2° 15:45 9.94 61% 153.8°
2041-02-23 Sat 40 — unknown 19:40–21:15 (good, 1.58 h) 79.2° 15:40 9.9 51% 144.4°
2041-02-24 Sun 38 — unknown 19:40–21:10 (good, 1.5 h) 79.2° 15:40 9.85 40% 133.0°
2041-02-25 Mon 37 — unknown 19:40–21:05 (good, 1.42 h) 79.2° 15:35 9.81 29% 120.5°
2041-02-26 Tue 34 — unknown 19:45–21:05 (good, 1.33 h) 79.2° 15:30 9.77 20% 107.2°
2041-02-27 Wed 32 — unknown 19:45–21:00 (good, 1.25 h) 79.2° 15:25 9.72 11% 93.5°
2041-02-28 Thu 31 — unknown 19:45–20:55 (good, 1.17 h) 79.2° 15:20 9.68 5% 79.4°
2041-03-01 Fri 29 — unknown 19:45–20:50 (good, 1.08 h) 79.2° 15:20 9.63 1% 65.3°
2041-03-02 Sat 26 — unknown 19:50–20:45 (good, 0.92 h) 79.2° 15:15 9.58 0% 51.5°
2041-03-03 Sun 25 — unknown 19:50–20:45 (good, 0.92 h) 79.2° 15:10 9.54 3% 38.5°
2041-03-04 Mon 22 — unknown 19:50–20:40 (good, 0.83 h) 79.2° 15:05 9.49 8% 27.5°
2041-03-05 Tue 19 — unknown 19:50–20:30 (good, 0.67 h) 79.2° 15:05 9.45 15% 21.0°
2041-03-06 Wed 15 — unknown 19:50–20:20 (good, 0.5 h) 79.2° 15:00 9.4 23% 22.4°
2041-03-07 Thu 11 — unknown 19:55–20:05 (good, 0.17 h) 79.2° 14:55 9.35 33% 30.2°
2041-03-08 Fri 9 — unknown 19:55–20:50 (marginal, 0.92 h) 79.2° 14:50 9.3 43% 40.3°
2041-03-09 Sat 7 — unknown 19:55–20:40 (marginal, 0.75 h) 79.2° 14:45 9.25 53% 51.1°
2041-03-10 Sun 6 — unknown 19:55–20:35 (marginal, 0.67 h) 79.2° 14:45 9.21 62% 62.2°
2041-03-11 Mon 5 — unknown 20:00–20:30 (marginal, 0.5 h) 79.2° 14:40 9.16 71% 73.3°
2041-03-12 Tue 4 — unknown 20:00–20:30 (marginal, 0.5 h) 79.2° 14:35 9.11 80% 84.4°
2041-03-13 Wed 4 — unknown 20:00–20:30 (marginal, 0.5 h) 79.2° 14:30 9.06 86% 95.4°
2041-03-14 Thu 4 — unknown 20:00–20:30 (marginal, 0.5 h) 79.2° 14:25 9.01 92% 106.5°
2041-03-15 Fri 4 — unknown 20:05–20:25 (marginal, 0.33 h) 79.2° 14:25 8.96 96% 117.5°
2041-03-16 Sat 3 — unknown 20:05–20:20 (marginal, 0.25 h) 79.2° 14:20 8.91 99% 128.3°
2041-03-17 Sun 3 — unknown 20:05–20:15 (marginal, 0.17 h) 79.2° 14:15 8.86 100% 138.9°
2041-03-18 Mon 3 — unknown 20:05–20:15 (marginal, 0.17 h) 79.2° 14:10 8.81 99% 148.7°
2041-03-19 Tue 2 — unknown 19:35–19:40 (marginal, 0.08 h) 79.2° 14:10 8.75 96% 156.5°
2041-03-20 Wed 1 — unknown — 79.2° 14:05 8.7 91% 159.6°
2041-03-21 Thu 1 — unknown — 79.2° 14:00 8.65 84% 155.7°
2041-03-22 Fri 1 — unknown — 79.2° 13:55 8.6 76% 147.0°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-02-21&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.