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: 11-15 (89), 11-16 (89), 11-17 (89), 11-18 (89), 11-19 (89) — by astronomy; check the weather when the night is within four days.

2036-11-15astronomy score per night — click a bar for that night2036-12-14

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-11-15 Sat	89	—	unknown	23:00–05:35 (good, 6.58 h)	42.9° 02:15	10.98	5%	122.5°
2036-11-16 Sun	89	—	unknown	22:55–05:30 (good, 6.58 h)	42.9° 02:10	11.0	2%	134.1°
2036-11-17 Mon	89	—	unknown	22:55–05:25 (good, 6.5 h)	42.9° 02:10	11.03	0%	144.4°
2036-11-18 Tue	89	—	unknown	22:50–05:25 (good, 6.58 h)	42.9° 02:05	11.06	1%	152.1°
2036-11-19 Wed	89	—	unknown	22:45–05:20 (good, 6.58 h)	42.9° 02:00	11.08	4%	155.1°
2036-11-20 Thu	89	—	unknown	22:40–05:15 (good, 6.58 h)	42.9° 01:55	11.11	9%	152.3°
2036-11-21 Fri	89	—	unknown	22:40–05:10 (good, 6.5 h)	42.9° 01:50	11.13	15%	145.3°
2036-11-22 Sat	89	—	unknown	22:35–05:05 (good, 6.5 h)	42.9° 01:50	11.16	23%	136.3°
2036-11-23 Sun	89	—	unknown	22:30–05:05 (good, 6.58 h)	42.9° 01:45	11.18	32%	126.4°
2036-11-24 Mon	89	—	unknown	22:30–05:00 (good, 6.5 h)	42.9° 01:40	11.2	40%	116.1°
2036-11-25 Tue	89	—	unknown	22:30–04:55 (good, 6.42 h)	42.9° 01:35	11.23	50%	105.5°
2036-11-26 Wed	89	—	unknown	22:35–04:50 (good, 6.25 h)	42.9° 01:30	11.25	59%	94.8°
2036-11-27 Thu	89	—	unknown	22:40–04:45 (good, 6.08 h)	42.9° 01:30	11.27	68%	83.8°
2036-11-28 Fri	87	—	unknown	23:35–04:45 (good, 5.17 h)	42.9° 01:25	11.29	77%	72.8°
2036-11-29 Sat	83	—	unknown	01:55–04:40 (good, 2.75 h)	42.9° 01:20	11.31	85%	61.6°
2036-11-30 Sun	46	—	unknown	22:15–05:05 (marginal, 6.83 h)	42.9° 01:15	11.32	92%	50.5°
2036-12-01 Mon	27	—	unknown	23:45–04:45 (marginal, 5.0 h)	42.9° 01:15	11.34	96%	39.9°
2036-12-02 Tue	15	—	unknown	03:15–04:05 (marginal, 0.83 h)	42.9° 01:10	11.36	99%	30.7°
2036-12-03 Wed	11	—	unknown	—	42.9° 01:05	11.37	100%	25.3°
2036-12-04 Thu	11	—	unknown	—	42.9° 01:00	11.39	98%	26.6°
2036-12-05 Fri	19	—	unknown	21:50–00:35 (marginal, 2.75 h)	42.9° 00:55	11.4	93%	34.0°
2036-12-06 Sat	35	—	unknown	21:20–03:55 (marginal, 6.58 h)	42.9° 00:55	11.41	86%	44.6°
2036-12-07 Sun	55	—	unknown	21:05–04:20 (marginal, 7.25 h)	42.9° 00:50	11.43	77%	56.7°
2036-12-08 Mon	82	—	unknown	21:30–02:35 (good, 5.08 h)	42.9° 00:45	11.44	66%	69.3°
2036-12-09 Tue	87	—	unknown	21:25–03:35 (good, 6.17 h)	42.9° 00:40	11.45	55%	82.1°
2036-12-10 Wed	89	—	unknown	21:25–03:45 (good, 6.33 h)	42.9° 00:35	11.46	44%	94.8°
2036-12-11 Thu	89	—	unknown	21:20–03:45 (good, 6.42 h)	42.9° 00:35	11.47	33%	107.3°
2036-12-12 Fri	89	—	unknown	21:15–03:45 (good, 6.5 h)	42.9° 00:30	11.48	23%	119.5°
2036-12-13 Sat	89	—	unknown	21:10–03:45 (good, 6.58 h)	42.9° 00:25	11.48	15%	131.0°
2036-12-14 Sun	89	—	unknown	21:05–03:40 (good, 6.58 h)	42.9° 00:20	11.49	8%	141.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-11-15&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.