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: 10-21 (89), 10-22 (89), 10-23 (89), 10-24 (89), 10-25 (89) — by astronomy; check the weather when the night is within four days.

2044-10-21astronomy score per night — click a bar for that night2044-11-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-10-21 Fri	89	—	unknown	01:40–06:10 (good, 4.5 h)	42.9° 04:55	10.1	1%	127.4°
2044-10-22 Sat	89	—	unknown	01:35–06:10 (good, 4.58 h)	42.9° 04:50	10.14	4%	135.8°
2044-10-23 Sun	89	—	unknown	01:30–06:15 (good, 4.75 h)	42.9° 04:45	10.18	9%	142.3°
2044-10-24 Mon	89	—	unknown	01:30–06:15 (good, 4.75 h)	42.9° 04:40	10.22	15%	145.9°
2044-10-25 Tue	89	—	unknown	01:25–06:15 (good, 4.83 h)	42.9° 04:40	10.26	23%	145.9°
2044-10-26 Wed	89	—	unknown	01:20–06:15 (good, 4.92 h)	42.9° 04:35	10.3	31%	142.4°
2044-10-27 Thu	89	—	unknown	01:15–06:20 (good, 5.08 h)	42.9° 04:30	10.34	40%	136.3°
2044-10-28 Fri	89	—	unknown	01:10–06:20 (good, 5.17 h)	42.9° 04:25	10.38	49%	128.5°
2044-10-29 Sat	89	—	unknown	01:10–05:20 (good, 5.17 h)	42.9° 03:20	10.41	59%	119.6°
2044-10-30 Sun	89	—	unknown	00:15–05:20 (good, 5.08 h)	42.9° 03:20	10.45	68%	110.0°
2044-10-31 Mon	89	—	unknown	00:20–05:20 (good, 5.0 h)	42.9° 03:15	10.49	77%	99.8°
2044-11-01 Tue	89	—	unknown	00:30–05:25 (good, 4.92 h)	42.9° 03:10	10.52	85%	89.2°
2044-11-02 Wed	87	—	unknown	01:50–05:25 (good, 3.58 h)	42.9° 03:05	10.56	92%	78.3°
2044-11-03 Thu	50	—	unknown	04:50–05:25 (good, 0.58 h)	42.9° 03:05	10.6	97%	67.2°
2044-11-04 Fri	34	—	unknown	00:05–05:25 (marginal, 5.33 h)	42.9° 03:00	10.63	99%	56.4°
2044-11-05 Sat	22	—	unknown	01:30–05:25 (marginal, 3.92 h)	42.9° 02:55	10.66	100%	46.4°
2044-11-06 Sun	15	—	unknown	04:00–05:30 (marginal, 1.5 h)	42.9° 02:50	10.7	97%	38.3°
2044-11-07 Mon	13	—	unknown	—	42.9° 02:45	10.73	92%	33.9°
2044-11-08 Tue	19	—	unknown	23:40–05:30 (marginal, 5.83 h)	42.9° 02:45	10.76	84%	34.7°
2044-11-09 Wed	33	—	unknown	23:10–05:30 (marginal, 6.33 h)	42.9° 02:40	10.8	75%	40.4°
2044-11-10 Thu	52	—	unknown	22:50–05:35 (marginal, 6.75 h)	42.9° 02:35	10.83	65%	49.2°
2044-11-11 Fri	68	—	unknown	23:35–04:30 (good, 4.92 h)	42.9° 02:30	10.86	53%	59.5°
2044-11-12 Sat	83	—	unknown	23:15–05:25 (good, 6.17 h)	42.9° 02:25	10.89	42%	70.5°
2044-11-13 Sun	88	—	unknown	23:10–05:30 (good, 6.33 h)	42.9° 02:25	10.92	32%	81.8°
2044-11-14 Mon	89	—	unknown	23:05–05:35 (good, 6.5 h)	42.9° 02:20	10.95	22%	93.0°
2044-11-15 Tue	89	—	unknown	23:00–05:30 (good, 6.5 h)	42.9° 02:15	10.98	14%	104.0°
2044-11-16 Wed	89	—	unknown	23:00–05:30 (good, 6.5 h)	42.9° 02:10	11.01	8%	114.5°
2044-11-17 Thu	89	—	unknown	22:55–05:25 (good, 6.5 h)	42.9° 02:10	11.03	3%	124.5°
2044-11-18 Fri	89	—	unknown	22:50–05:25 (good, 6.58 h)	42.9° 02:05	11.06	1%	133.3°
2044-11-19 Sat	89	—	unknown	22:45–05:20 (good, 6.58 h)	42.9° 02:00	11.09	0%	140.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-10-21&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.