← single night · whole-night plan

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: 08-06 (41), 08-05 (39), 08-04 (38), 08-07 (37), 08-03 (35) — by astronomy; check the weather when the night is within four days.
2025-07-15astronomy score per night — click a bar for that night2025-08-13
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2025-07-15 Tue 1 94 1 — 72.5° 09:30 5.01 73% 63.3°
2025-07-16 Wed 2 98 2 — 72.5° 09:30 5.05 62% 49.4°
2025-07-17 Thu 2 9 0 — 72.5° 09:25 5.1 51% 35.3°
2025-07-18 Fri 4 66 3 03:50–04:00 (marginal, 0.17 h) 72.5° 09:20 5.14 40% 21.1°
2025-07-19 Sat 5 100 5 04:25–04:55 (marginal, 0.5 h) 72.5° 09:15 5.19 29% 6.9°
2025-07-20 Sun 7 100 7 04:15–04:55 (marginal, 0.67 h) 72.5° 09:10 5.24 19% 7.5°
2025-07-21 Mon 10 100 10 04:05–04:10 (good, 0.08 h) 72.5° 09:10 5.28 11% 21.8°
2025-07-22 Tue 12 99 12 04:00–04:10 (good, 0.17 h) 72.5° 09:05 5.33 5% 36.1°
2025-07-23 Wed 15 100 15 03:55–04:10 (good, 0.25 h) 72.5° 09:00 5.38 1% 50.2°
2025-07-24 Thu 17 100 17 03:50–04:15 (good, 0.42 h) 72.5° 08:55 5.43 0% 64.1°
2025-07-25 Fri 19 100 19 03:45–04:15 (good, 0.5 h) 72.5° 08:50 5.48 2% 77.7°
2025-07-26 Sat 20 100 20 03:45–04:15 (good, 0.5 h) 72.5° 08:50 5.54 5% 91.0°
2025-07-27 Sun 23 92 21 03:55–04:20 (good, 0.42 h) 72.5° 08:45 5.59 11% 103.9°
2025-07-28 Mon 25 99 25 03:35–04:20 (good, 0.75 h) 72.5° 08:40 5.64 18% 116.5°
2025-07-29 Tue 26 99 26 03:30–04:20 (good, 0.83 h) 72.5° 08:35 5.7 26% 128.8°
2025-07-30 Wed 28 0 0 — 72.5° 08:35 5.75 35% 140.9°
2025-07-31 Thu 30 33 10 04:00–04:25 (marginal, 0.42 h) 72.5° 08:30 5.81 44% 152.8°
2025-08-01 Fri 32 87 28 03:35–04:25 (good, 0.83 h) 72.5° 08:25 5.86 54% 164.6°
2025-08-02 Sat 33 100 33 03:15–04:25 (good, 1.17 h) 72.5° 08:20 5.92 63% 176.4°
2025-08-03 Sun 35 97 34 03:10–04:30 (good, 1.33 h) 72.5° 08:15 5.97 72% 171.5°
2025-08-04 Mon 38 52 20 03:15–04:00 (good, 0.75 h) 72.5° 08:15 6.03 80% 159.4°
2025-08-05 Tue 39 64 25 04:00–04:30 (good, 0.5 h) 72.5° 08:10 6.08 88% 147.1°
2025-08-06 Wed 41 77 32 03:30–04:35 (good, 1.08 h) 72.5° 08:05 6.14 94% 134.4°
2025-08-07 Thu 37 70 26 04:00–04:35 (good, 0.58 h) 72.5° 08:00 6.2 98% 121.5°
2025-08-08 Fri 33 100 33 03:10–04:35 (good, 1.42 h) 72.5° 07:55 6.25 100% 108.2°
2025-08-09 Sat 28 100 28 03:20–04:40 (good, 1.33 h) 72.5° 07:55 6.31 100% 94.7°
2025-08-10 Sun 23 100 23 04:30–04:40 (good, 0.17 h) 72.5° 07:50 6.37 97% 80.9°
2025-08-11 Mon 18 100 18 02:30–04:40 (marginal, 2.17 h) 72.5° 07:45 6.43 92% 66.9°
2025-08-12 Tue 15 100 15 02:30–04:45 (marginal, 2.25 h) 72.5° 07:40 6.48 84% 52.8°
2025-08-13 Wed 14 100 14 02:25–04:45 (marginal, 2.33 h) 72.5° 07:40 6.54 75% 38.6°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2025-07-15&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.