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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 Seven Sisters: 03-15 (43), 03-16 (42), 03-17 (40), 03-18 (38), 03-19 (36) — by astronomy; check the weather when the night is within four days.
2042-03-15astronomy score per night — click a bar for that night2042-04-13
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2042-03-15 Sat 43 — unknown 20:05–21:50 (good, 1.75 h) 72.5° 16:35 8.97 40% 142.8°
2042-03-16 Sun 42 — unknown 20:05–21:45 (good, 1.67 h) 72.5° 16:35 8.92 30% 129.3°
2042-03-17 Mon 40 — unknown 20:05–21:40 (good, 1.58 h) 72.5° 16:30 8.87 20% 115.3°
2042-03-18 Tue 38 — unknown 20:05–21:35 (good, 1.5 h) 72.5° 16:25 8.82 11% 100.8°
2042-03-19 Wed 36 — unknown 20:10–21:30 (good, 1.33 h) 72.5° 16:20 8.77 5% 86.0°
2042-03-20 Thu 34 — unknown 20:10–21:30 (good, 1.33 h) 72.5° 16:15 8.72 1% 70.9°
2042-03-21 Fri 32 — unknown 20:10–21:25 (good, 1.25 h) 72.5° 16:15 8.66 0% 55.6°
2042-03-22 Sat 30 — unknown 20:10–21:20 (good, 1.17 h) 72.5° 16:10 8.61 2% 40.4°
2042-03-23 Sun 27 — unknown 20:15–21:15 (good, 1.0 h) 72.5° 16:05 8.56 7% 25.4°
2042-03-24 Mon 23 — unknown 20:15–21:05 (good, 0.83 h) 72.5° 16:00 8.51 15% 10.7°
2042-03-25 Tue 18 — unknown 20:15–20:55 (good, 0.67 h) 72.5° 15:55 8.45 24% 3.8°
2042-03-26 Wed 14 — unknown 20:15–20:40 (good, 0.42 h) 72.5° 15:55 8.4 34% 17.4°
2042-03-27 Thu 10 — unknown 20:20–21:25 (marginal, 1.08 h) 72.5° 15:50 8.35 44% 30.7°
2042-03-28 Fri 8 — unknown 20:20–21:15 (marginal, 0.92 h) 72.5° 15:45 8.29 55% 43.6°
2042-03-29 Sat 7 — unknown 20:20–21:10 (marginal, 0.83 h) 72.5° 15:40 8.24 64% 56.2°
2042-03-30 Sun 6 — unknown 21:20–22:05 (marginal, 0.75 h) 72.5° 16:40 8.18 74% 68.5°
2042-03-31 Mon 6 — unknown 21:25–22:05 (marginal, 0.67 h) 72.5° 16:35 8.13 82% 80.6°
2042-04-01 Tue 6 — unknown 21:25–22:05 (marginal, 0.67 h) 72.5° 16:30 8.08 88% 92.5°
2042-04-02 Wed 7 — unknown 21:25–22:05 (marginal, 0.67 h) 72.5° 16:25 8.02 94% 104.4°
2042-04-03 Thu 7 — unknown 21:25–22:00 (marginal, 0.58 h) 72.5° 16:20 7.97 98% 116.2°
2042-04-04 Fri 6 — unknown 21:30–21:55 (marginal, 0.42 h) 72.5° 16:20 7.91 100% 128.1°
2042-04-05 Sat 5 — unknown 21:30–21:50 (marginal, 0.33 h) 72.5° 16:15 7.85 100% 139.9°
2042-04-06 Sun 5 — unknown 21:30–21:50 (marginal, 0.33 h) 72.5° 16:10 7.8 98% 151.8°
2042-04-07 Mon 4 — unknown 21:00–21:15 (marginal, 0.25 h) 72.5° 16:05 7.74 95% 163.8°
2042-04-08 Tue 3 — unknown 21:00–21:15 (marginal, 0.25 h) 72.5° 16:00 7.69 90% 175.8°
2042-04-09 Wed 2 — unknown 21:00–21:10 (marginal, 0.17 h) 72.5° 16:00 7.63 83% 171.6°
2042-04-10 Thu 2 — unknown 21:00–21:05 (marginal, 0.08 h) 72.5° 15:55 7.57 75% 159.2°
2042-04-11 Fri 1 — unknown — 72.5° 15:50 7.52 66% 146.4°
2042-04-12 Sat 1 — unknown — 72.5° 15:45 7.46 56% 133.4°
2042-04-13 Sun 1 — unknown — 72.5° 15:45 7.4 45% 120.0°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2042-03-15&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.