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: 12-10 (89), 12-11 (89), 12-12 (89), 12-27 (89), 12-28 (89) — by astronomy; check the weather when the night is within four days.

2029-12-10astronomy score per night — click a bar for that night2030-01-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-12-10 Mon	89	—	unknown	21:30–03:55 (good, 6.42 h)	42.9° 00:40	11.46	32%	114.0°
2029-12-11 Tue	89	—	unknown	21:30–03:55 (good, 6.42 h)	42.9° 00:35	11.47	42%	103.1°
2029-12-12 Wed	89	—	unknown	21:30–03:50 (good, 6.33 h)	42.9° 00:30	11.47	52%	92.3°
2029-12-13 Thu	87	—	unknown	21:40–03:45 (good, 6.08 h)	42.9° 00:25	11.48	61%	81.7°
2029-12-14 Fri	83	—	unknown	22:40–03:40 (good, 5.0 h)	42.9° 00:20	11.49	70%	71.4°
2029-12-15 Sat	66	—	unknown	01:15–03:05 (good, 1.83 h)	42.9° 00:20	11.49	79%	61.3°
2029-12-16 Sun	43	—	unknown	21:05–04:00 (marginal, 6.92 h)	42.9° 00:15	11.5	86%	51.7°
2029-12-17 Mon	28	—	unknown	21:35–03:45 (marginal, 6.17 h)	42.9° 00:10	11.5	92%	42.8°
2029-12-18 Tue	17	—	unknown	01:25–03:10 (marginal, 1.75 h)	42.9° 00:05	11.5	96%	35.2°
2029-12-19 Wed	10	—	unknown	—	42.9° 00:05	11.51	99%	30.0°
2029-12-20 Thu	9	—	unknown	—	42.9° 00:00	11.51	100%	28.9°
2029-12-21 Fri	13	—	unknown	—	42.9° 23:55	11.51	99%	32.4°
2029-12-22 Sat	23	—	unknown	20:30–00:35 (marginal, 4.08 h)	42.9° 23:50	11.51	96%	39.5°
2029-12-23 Sun	38	—	unknown	20:10–02:50 (marginal, 6.67 h)	42.9° 23:45	11.51	91%	48.7°
2029-12-24 Mon	69	—	unknown	20:30–20:50 (good, 0.33 h)	42.9° 23:45	11.5	84%	59.1°
2029-12-25 Tue	84	—	unknown	20:25–01:05 (good, 4.67 h)	42.9° 23:40	11.5	76%	70.2°
2029-12-26 Wed	88	—	unknown	20:20–02:25 (good, 6.08 h)	42.9° 23:35	11.49	66%	81.9°
2029-12-27 Thu	89	—	unknown	20:15–02:35 (good, 6.33 h)	42.9° 23:30	11.49	55%	93.9°
2029-12-28 Fri	89	—	unknown	20:15–02:40 (good, 6.42 h)	42.9° 23:25	11.48	44%	106.0°
2029-12-29 Sat	89	—	unknown	20:10–02:40 (good, 6.5 h)	42.9° 23:25	11.48	33%	118.1°
2029-12-30 Sun	89	—	unknown	20:05–02:40 (good, 6.58 h)	42.9° 23:20	11.47	23%	129.8°
2029-12-31 Mon	89	—	unknown	20:00–02:35 (good, 6.58 h)	42.9° 23:15	11.46	14%	140.4°
2030-01-01 Tue	89	—	unknown	19:55–02:30 (good, 6.58 h)	42.9° 23:10	11.45	6%	148.3°
2030-01-02 Wed	89	—	unknown	19:55–02:25 (good, 6.5 h)	42.9° 23:10	11.44	2%	151.2°
2030-01-03 Thu	89	—	unknown	19:50–02:25 (good, 6.58 h)	42.9° 23:05	11.43	0%	147.7°
2030-01-04 Fri	89	—	unknown	19:45–02:20 (good, 6.58 h)	42.9° 23:00	11.42	1%	139.7°
2030-01-05 Sat	89	—	unknown	19:40–02:15 (good, 6.58 h)	42.9° 22:55	11.4	4%	129.4°
2030-01-06 Sun	89	—	unknown	19:40–02:10 (good, 6.5 h)	42.9° 22:50	11.39	10%	118.4°
2030-01-07 Mon	89	—	unknown	19:35–02:05 (good, 6.5 h)	42.9° 22:50	11.37	17%	107.2°
2030-01-08 Tue	89	—	unknown	19:35–02:05 (good, 6.5 h)	42.9° 22:45	11.36	25%	96.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-12-10&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.