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: 03-14 (42), 03-13 (41), 03-15 (40), 03-16 (39), 03-17 (38) — by astronomy; check the weather when the night is within four days.

2047-03-11astronomy score per night — click a bar for that night2047-04-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-03-11 Mon	24	—	unknown	20:00–20:30 (good, 0.5 h)	42.9° 18:40	9.18	100%	84.9°
2047-03-12 Tue	31	—	unknown	20:00–21:30 (good, 1.5 h)	42.9° 18:40	9.13	99%	97.8°
2047-03-13 Wed	41	—	unknown	20:00–21:40 (good, 1.67 h)	42.9° 18:35	9.08	95%	110.5°
2047-03-14 Thu	42	—	unknown	20:00–21:50 (good, 1.83 h)	42.9° 18:30	9.03	88%	122.7°
2047-03-15 Fri	40	—	unknown	20:05–21:45 (good, 1.67 h)	42.9° 18:25	8.98	79%	133.7°
2047-03-16 Sat	39	—	unknown	20:05–21:40 (good, 1.58 h)	42.9° 18:20	8.93	69%	142.7°
2047-03-17 Sun	38	—	unknown	20:05–21:35 (good, 1.5 h)	42.9° 18:20	8.88	58%	148.0°
2047-03-18 Mon	36	—	unknown	20:05–21:35 (good, 1.5 h)	42.9° 18:15	8.83	47%	148.4°
2047-03-19 Tue	33	—	unknown	20:10–21:30 (good, 1.33 h)	42.9° 18:10	8.78	37%	144.0°
2047-03-20 Wed	32	—	unknown	20:10–21:25 (good, 1.25 h)	42.9° 18:05	8.73	27%	136.5°
2047-03-21 Thu	30	—	unknown	20:10–21:20 (good, 1.17 h)	42.9° 18:00	8.67	18%	127.4°
2047-03-22 Fri	29	—	unknown	20:10–21:15 (good, 1.08 h)	42.9° 18:00	8.62	12%	117.6°
2047-03-23 Sat	27	—	unknown	20:15–21:15 (good, 1.0 h)	42.9° 17:55	8.57	6%	107.4°
2047-03-24 Sun	25	—	unknown	20:15–21:10 (good, 0.92 h)	42.9° 17:50	8.52	2%	97.1°
2047-03-25 Mon	24	—	unknown	20:15–21:05 (good, 0.83 h)	42.9° 17:45	8.46	0%	86.9°
2047-03-26 Tue	23	—	unknown	20:15–21:00 (good, 0.75 h)	42.9° 17:45	8.41	0%	76.7°
2047-03-27 Wed	21	—	unknown	20:20–21:00 (good, 0.67 h)	42.9° 17:40	8.36	2%	66.8°
2047-03-28 Thu	18	—	unknown	20:20–20:50 (good, 0.5 h)	42.9° 17:35	8.3	6%	57.2°
2047-03-29 Fri	16	—	unknown	20:20–20:45 (good, 0.42 h)	42.9° 17:30	8.25	10%	48.2°
2047-03-30 Sat	13	—	unknown	20:20–20:35 (good, 0.25 h)	42.9° 17:25	8.2	17%	40.3°
2047-03-31 Sun	9	—	unknown	20:50–22:15 (marginal, 1.42 h)	42.9° 18:25	8.14	25%	34.1°
2047-04-01 Mon	7	—	unknown	21:25–22:10 (marginal, 0.75 h)	42.9° 18:20	8.09	33%	31.1°
2047-04-02 Tue	5	—	unknown	21:25–22:00 (marginal, 0.58 h)	42.9° 18:15	8.03	43%	32.2°
2047-04-03 Wed	4	—	unknown	21:25–21:50 (marginal, 0.42 h)	42.9° 18:10	7.98	53%	37.4°
2047-04-04 Thu	2	—	unknown	21:30–21:40 (marginal, 0.17 h)	42.9° 18:05	7.92	63%	45.4°
2047-04-05 Fri	2	—	unknown	21:30–21:35 (marginal, 0.08 h)	42.9° 18:05	7.87	74%	55.5°
2047-04-06 Sat	2	—	unknown	21:30–21:35 (marginal, 0.08 h)	42.9° 18:00	7.81	83%	66.8°
2047-04-07 Sun	2	—	unknown	—	42.9° 17:55	7.75	91%	79.0°
2047-04-08 Mon	1	—	unknown	21:35–21:40 (marginal, 0.08 h)	42.9° 17:50	7.7	96%	91.7°
2047-04-09 Tue	2	—	unknown	21:35–21:40 (marginal, 0.08 h)	42.9° 17:50	7.64	99%	104.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-03-11&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.