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: 03-11 (45), 03-12 (45), 03-13 (45), 03-10 (44), 03-14 (43) — by astronomy; check the weather when the night is within four days.

2031-03-08astronomy score per night — click a bar for that night2031-04-06

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2031-03-08 Sat	25	—	unknown	19:55–20:15 (good, 0.33 h)	42.9° 18:55	9.33	100%	80.8°
2031-03-09 Sun	31	—	unknown	19:55–21:35 (good, 1.67 h)	42.9° 18:50	9.28	99%	92.5°
2031-03-10 Mon	44	—	unknown	19:55–21:45 (good, 1.83 h)	42.9° 18:45	9.23	96%	104.4°
2031-03-11 Tue	45	—	unknown	20:00–21:50 (good, 1.83 h)	42.9° 18:40	9.18	91%	116.3°
2031-03-12 Wed	45	—	unknown	20:00–21:55 (good, 1.92 h)	42.9° 18:35	9.14	84%	127.9°
2031-03-13 Thu	45	—	unknown	20:00–21:55 (good, 1.92 h)	42.9° 18:35	9.09	75%	138.8°
2031-03-14 Fri	43	—	unknown	20:00–21:50 (good, 1.83 h)	42.9° 18:30	9.04	65%	147.8°
2031-03-15 Sat	40	—	unknown	20:05–21:45 (good, 1.67 h)	42.9° 18:25	8.99	54%	153.0°
2031-03-16 Sun	38	—	unknown	20:05–21:40 (good, 1.58 h)	42.9° 18:20	8.94	42%	151.9°
2031-03-17 Mon	38	—	unknown	20:05–21:35 (good, 1.5 h)	42.9° 18:20	8.89	31%	145.0°
2031-03-18 Tue	36	—	unknown	20:05–21:35 (good, 1.5 h)	42.9° 18:15	8.84	21%	134.9°
2031-03-19 Wed	34	—	unknown	20:05–21:30 (good, 1.42 h)	42.9° 18:10	8.78	13%	123.4°
2031-03-20 Thu	32	—	unknown	20:10–21:25 (good, 1.25 h)	42.9° 18:05	8.73	6%	111.2°
2031-03-21 Fri	30	—	unknown	20:10–21:20 (good, 1.17 h)	42.9° 18:00	8.68	2%	98.9°
2031-03-22 Sat	29	—	unknown	20:10–21:15 (good, 1.08 h)	42.9° 18:00	8.63	0%	86.6°
2031-03-23 Sun	28	—	unknown	20:10–21:15 (good, 1.08 h)	42.9° 17:55	8.58	1%	74.7°
2031-03-24 Mon	25	—	unknown	20:15–21:10 (good, 0.92 h)	42.9° 17:50	8.52	4%	63.1°
2031-03-25 Tue	22	—	unknown	20:15–21:05 (good, 0.83 h)	42.9° 17:45	8.47	8%	52.2°
2031-03-26 Wed	19	—	unknown	20:15–20:55 (good, 0.67 h)	42.9° 17:40	8.42	15%	42.3°
2031-03-27 Thu	16	—	unknown	20:20–20:45 (good, 0.42 h)	42.9° 17:40	8.36	22%	34.0°
2031-03-28 Fri	12	—	unknown	20:20–20:30 (good, 0.17 h)	42.9° 17:35	8.31	31%	28.2°
2031-03-29 Sat	9	—	unknown	20:20–21:20 (marginal, 1.0 h)	42.9° 17:30	8.26	40%	26.6°
2031-03-30 Sun	6	—	unknown	21:20–22:10 (marginal, 0.83 h)	42.9° 18:25	8.2	49%	29.6°
2031-03-31 Mon	4	—	unknown	21:25–21:55 (marginal, 0.5 h)	42.9° 18:25	8.15	59%	36.2°
2031-04-01 Tue	4	—	unknown	21:25–21:50 (marginal, 0.42 h)	42.9° 18:20	8.09	68%	44.8°
2031-04-02 Wed	3	—	unknown	21:25–21:45 (marginal, 0.33 h)	42.9° 18:15	8.04	76%	54.7°
2031-04-03 Thu	3	—	unknown	21:25–21:45 (marginal, 0.33 h)	42.9° 18:10	7.98	84%	65.3°
2031-04-04 Fri	3	—	unknown	21:30–21:45 (marginal, 0.25 h)	42.9° 18:05	7.93	91%	76.5°
2031-04-05 Sat	3	—	unknown	21:30–21:50 (marginal, 0.33 h)	42.9° 18:05	7.87	96%	88.1°
2031-04-06 Sun	3	—	unknown	21:30–21:50 (marginal, 0.33 h)	42.9° 18:00	7.82	99%	100.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2031-03-08&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.