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: 12-02 (89), 12-03 (89), 12-04 (89), 12-05 (89), 12-06 (89) — by astronomy; check the weather when the night is within four days.

2045-11-27astronomy score per night — click a bar for that night2045-12-26

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-11-27 Mon	28	—	unknown	22:05–04:25 (marginal, 6.33 h)	42.9° 01:30	11.26	86%	40.5°
2045-11-28 Tue	46	—	unknown	21:45–04:45 (marginal, 7.0 h)	42.9° 01:25	11.28	77%	49.6°
2045-11-29 Wed	64	—	unknown	22:35–02:00 (good, 3.42 h)	42.9° 01:20	11.3	67%	60.2°
2045-11-30 Thu	84	—	unknown	22:05–04:05 (good, 6.0 h)	42.9° 01:20	11.32	56%	71.6°
2045-12-01 Fri	88	—	unknown	22:00–04:15 (good, 6.25 h)	42.9° 01:15	11.34	44%	83.4°
2045-12-02 Sat	89	—	unknown	21:55–04:20 (good, 6.42 h)	42.9° 01:10	11.35	33%	95.2°
2045-12-03 Sun	89	—	unknown	21:50–04:20 (good, 6.5 h)	42.9° 01:05	11.37	23%	106.8°
2045-12-04 Mon	89	—	unknown	21:50–04:20 (good, 6.5 h)	42.9° 01:00	11.39	14%	118.0°
2045-12-05 Tue	89	—	unknown	21:45–04:15 (good, 6.5 h)	42.9° 01:00	11.4	8%	128.5°
2045-12-06 Wed	89	—	unknown	21:40–04:15 (good, 6.58 h)	42.9° 00:55	11.41	3%	137.5°
2045-12-07 Thu	89	—	unknown	21:35–04:10 (good, 6.58 h)	42.9° 00:50	11.43	0%	144.2°
2045-12-08 Fri	89	—	unknown	21:30–04:05 (good, 6.58 h)	42.9° 00:45	11.44	0%	147.3°
2045-12-09 Sat	89	—	unknown	21:30–04:00 (good, 6.5 h)	42.9° 00:40	11.45	2%	146.0°
2045-12-10 Sun	89	—	unknown	21:25–04:00 (good, 6.58 h)	42.9° 00:40	11.46	6%	140.9°
2045-12-11 Mon	89	—	unknown	21:20–03:55 (good, 6.58 h)	42.9° 00:35	11.47	12%	133.5°
2045-12-12 Tue	89	—	unknown	21:15–03:50 (good, 6.58 h)	42.9° 00:30	11.47	18%	124.9°
2045-12-13 Wed	89	—	unknown	21:15–03:45 (good, 6.5 h)	42.9° 00:25	11.48	26%	115.6°
2045-12-14 Thu	89	—	unknown	21:15–03:40 (good, 6.42 h)	42.9° 00:25	11.49	35%	105.9°
2045-12-15 Fri	89	—	unknown	21:15–03:40 (good, 6.42 h)	42.9° 00:20	11.49	44%	96.1°
2045-12-16 Sat	88	—	unknown	21:20–03:35 (good, 6.25 h)	42.9° 00:15	11.5	54%	86.0°
2045-12-17 Sun	86	—	unknown	21:30–03:30 (good, 6.0 h)	42.9° 00:10	11.5	63%	75.9°
2045-12-18 Mon	80	—	unknown	23:15–03:25 (good, 4.17 h)	42.9° 00:05	11.5	72%	65.9°
2045-12-19 Tue	51	—	unknown	20:45–03:55 (marginal, 7.17 h)	42.9° 00:05	11.51	81%	55.9°
2045-12-20 Wed	34	—	unknown	21:05–03:35 (marginal, 6.5 h)	42.9° 00:00	11.51	88%	46.6°
2045-12-21 Thu	20	—	unknown	23:55–03:10 (marginal, 3.25 h)	42.9° 23:55	11.51	94%	38.6°
2045-12-22 Fri	11	—	unknown	—	42.9° 23:50	11.51	98%	33.5°
2045-12-23 Sat	10	—	unknown	—	42.9° 23:45	11.5	100%	33.1°
2045-12-24 Sun	16	—	unknown	20:45–22:20 (marginal, 1.58 h)	42.9° 23:45	11.5	99%	37.9°
2045-12-25 Mon	29	—	unknown	20:10–02:15 (marginal, 6.08 h)	42.9° 23:40	11.5	95%	46.4°
2045-12-26 Tue	48	—	unknown	19:50–02:50 (marginal, 7.0 h)	42.9° 23:35	11.49	89%	57.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-11-27&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.