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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: 03-16 (41), 03-17 (39), 03-18 (37), 03-19 (33), 03-20 (29) — by astronomy; check the weather when the night is within four days.
2037-03-16astronomy score per night — click a bar for that night2037-04-14
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2037-03-16 Mon 41 — unknown 20:05–21:40 (good, 1.58 h) 72.5° 16:30 8.91 0% 64.1°
2037-03-17 Tue 39 — unknown 20:05–21:40 (good, 1.58 h) 72.5° 16:30 8.86 1% 52.3°
2037-03-18 Wed 37 — unknown 20:05–21:35 (good, 1.5 h) 72.5° 16:25 8.81 4% 40.5°
2037-03-19 Thu 33 — unknown 20:10–21:30 (good, 1.33 h) 72.5° 16:20 8.76 8% 28.8°
2037-03-20 Fri 29 — unknown 20:10–21:20 (good, 1.17 h) 72.5° 16:15 8.7 14% 17.5°
2037-03-21 Sat 24 — unknown 20:10–21:10 (good, 1.0 h) 72.5° 16:10 8.65 22% 9.2°
2037-03-22 Sun 19 — unknown 20:10–21:00 (good, 0.83 h) 72.5° 16:10 8.6 31% 13.3°
2037-03-23 Mon 14 — unknown 20:15–21:40 (marginal, 1.42 h) 72.5° 16:05 8.55 41% 24.6°
2037-03-24 Tue 11 — unknown 20:15–21:30 (marginal, 1.25 h) 72.5° 16:00 8.5 52% 37.4°
2037-03-25 Wed 9 — unknown 20:15–21:25 (marginal, 1.17 h) 72.5° 15:55 8.44 63% 50.8°
2037-03-26 Thu 9 — unknown 20:15–21:20 (marginal, 1.08 h) 72.5° 15:50 8.39 73% 64.7°
2037-03-27 Fri 9 — unknown 20:20–21:20 (marginal, 1.0 h) 72.5° 15:50 8.34 83% 79.1°
2037-03-28 Sat 10 — unknown 20:20–21:20 (marginal, 1.0 h) 72.5° 15:45 8.28 91% 93.7°
2037-03-29 Sun 12 — unknown 21:20–21:30 (good, 0.17 h) 72.5° 16:40 8.23 97% 108.6°
2037-03-30 Mon 13 — unknown 21:20–21:35 (good, 0.25 h) 72.5° 16:35 8.17 100% 123.5°
2037-03-31 Tue 11 — unknown 21:25–21:35 (good, 0.17 h) 72.5° 16:35 8.12 99% 138.2°
2037-04-01 Wed 10 — unknown 21:25–21:30 (good, 0.08 h) 72.5° 16:30 8.06 96% 152.4°
2037-04-02 Thu 11 — unknown 21:25–21:35 (good, 0.17 h) 72.5° 16:25 8.01 91% 165.3°
2037-04-03 Fri 8 — unknown 20:55–22:00 (marginal, 1.08 h) 72.5° 16:20 7.95 84% 171.0°
2037-04-04 Sat 7 — unknown 20:55–21:55 (marginal, 1.0 h) 72.5° 16:15 7.9 75% 162.3°
2037-04-05 Sun 6 — unknown 20:55–21:25 (marginal, 0.5 h) 72.5° 16:15 7.84 65% 150.3°
2037-04-06 Mon 5 — unknown 20:55–21:20 (marginal, 0.42 h) 72.5° 16:10 7.79 55% 138.1°
2037-04-07 Tue 3 — unknown 21:00–21:15 (marginal, 0.25 h) 72.5° 16:05 7.73 46% 126.0°
2037-04-08 Wed 3 — unknown 21:00–21:10 (marginal, 0.17 h) 72.5° 16:00 7.67 36% 114.1°
2037-04-09 Thu 2 — unknown 21:00–21:10 (marginal, 0.17 h) 72.5° 15:55 7.62 27% 102.4°
2037-04-10 Fri 1 — unknown 21:00–21:05 (marginal, 0.08 h) 72.5° 15:55 7.56 19% 90.7°
2037-04-11 Sat 1 — unknown — 72.5° 15:50 7.5 12% 79.0°
2037-04-12 Sun 1 — unknown — 72.5° 15:45 7.45 7% 67.3°
2037-04-13 Mon 1 — unknown — 72.5° 15:40 7.39 3% 55.5°
2037-04-14 Tue 1 — unknown — 72.5° 15:40 7.33 1% 43.7°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-03-16&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.