← 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 Great Orion Nebula: 09-08 (23), 09-07 (20), 09-06 (17), 09-05 (13), 09-04 (8) — by astronomy; check the weather when the night is within four days.
2045-08-10astronomy score per night — click a bar for that night2045-09-08
night ofastronomyweatheroverall best windowhighestdark hMoonMoon sep.
2045-08-10 Thu 0 — unknown — 42.9° 09:40 6.38 5% 42.7°
2045-08-11 Fri 0 — unknown — 42.9° 09:35 6.44 1% 52.7°
2045-08-12 Sat 0 — unknown — 42.9° 09:30 6.49 0% 64.3°
2045-08-13 Sun 0 — unknown — 42.9° 09:25 6.55 2% 76.7°
2045-08-14 Mon 0 — unknown — 42.9° 09:20 6.61 7% 89.2°
2045-08-15 Tue 0 — unknown — 42.9° 09:20 6.67 14% 101.4°
2045-08-16 Wed 0 — unknown — 42.9° 09:15 6.72 24% 113.0°
2045-08-17 Thu 0 — unknown — 42.9° 09:10 6.78 34% 123.8°
2045-08-18 Fri 0 — unknown — 42.9° 09:05 6.84 44% 133.2°
2045-08-19 Sat 1 — unknown — 42.9° 09:05 6.9 55% 140.8°
2045-08-20 Sun 1 — unknown — 42.9° 09:00 6.95 64% 145.6°
2045-08-21 Mon 1 — unknown — 42.9° 08:55 7.01 74% 146.7°
2045-08-22 Tue 1 — unknown — 42.9° 08:50 7.07 82% 144.0°
2045-08-23 Wed 2 — unknown — 42.9° 08:45 7.13 88% 138.3°
2045-08-24 Thu 2 — unknown 05:30–05:40 (marginal, 0.17 h) 42.9° 08:45 7.18 94% 130.8°
2045-08-25 Fri 3 — unknown 05:25–05:40 (marginal, 0.25 h) 42.9° 08:40 7.24 98% 122.1°
2045-08-26 Sat 3 — unknown 04:50–05:05 (marginal, 0.25 h) 42.9° 08:35 7.3 100% 112.9°
2045-08-27 Sun 3 — unknown 04:45–05:05 (marginal, 0.33 h) 42.9° 08:30 7.35 100% 103.2°
2045-08-28 Mon 4 — unknown 04:45–05:05 (marginal, 0.33 h) 42.9° 08:25 7.41 98% 93.2°
2045-08-29 Tue 3 — unknown 04:45–05:10 (marginal, 0.42 h) 42.9° 08:25 7.47 95% 83.1°
2045-08-30 Wed 3 — unknown 04:50–05:10 (marginal, 0.33 h) 42.9° 08:20 7.52 90% 73.1°
2045-08-31 Thu 3 — unknown 04:50–05:10 (marginal, 0.33 h) 42.9° 08:15 7.58 83% 63.1°
2045-09-01 Fri 4 — unknown 04:50–05:15 (marginal, 0.42 h) 42.9° 08:10 7.63 75% 53.5°
2045-09-02 Sat 5 — unknown 04:45–05:15 (marginal, 0.5 h) 42.9° 08:10 7.69 66% 44.8°
2045-09-03 Sun 6 — unknown 04:30–05:15 (marginal, 0.75 h) 42.9° 08:05 7.74 55% 37.7°
2045-09-04 Mon 8 — unknown 04:20–05:15 (marginal, 0.92 h) 42.9° 08:00 7.8 44% 33.6°
2045-09-05 Tue 13 — unknown 05:10–05:20 (good, 0.17 h) 42.9° 07:55 7.86 34% 34.1°
2045-09-06 Wed 17 — unknown 04:50–05:20 (good, 0.5 h) 42.9° 07:50 7.91 23% 39.4°
2045-09-07 Thu 20 — unknown 04:40–05:20 (good, 0.67 h) 42.9° 07:50 7.96 14% 48.1°
2045-09-08 Fri 23 — unknown 04:30–05:20 (good, 0.83 h) 42.9° 07:45 8.02 7% 59.0°

Download: CSV · JSON


💡 API
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-08-10&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.