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: 12-04 (89), 12-05 (89), 12-06 (89), 12-07 (89), 12-08 (89) — by astronomy; check the weather when the night is within four days.

2034-12-04astronomy score per night — click a bar for that night2035-01-02

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-12-04 Mon	89	—	unknown	21:50–04:15 (good, 6.42 h)	42.9° 01:05	11.38	28%	104.2°
2034-12-05 Tue	89	—	unknown	21:45–04:15 (good, 6.5 h)	42.9° 01:00	11.39	20%	115.1°
2034-12-06 Wed	89	—	unknown	21:40–04:15 (good, 6.58 h)	42.9° 00:55	11.41	13%	125.7°
2034-12-07 Thu	89	—	unknown	21:35–04:10 (good, 6.58 h)	42.9° 00:50	11.42	8%	135.8°
2034-12-08 Fri	89	—	unknown	21:35–04:05 (good, 6.5 h)	42.9° 00:45	11.43	3%	144.9°
2034-12-09 Sat	89	—	unknown	21:30–04:00 (good, 6.5 h)	42.9° 00:45	11.44	1%	152.3°
2034-12-10 Sun	89	—	unknown	21:25–04:00 (good, 6.58 h)	42.9° 00:40	11.45	0%	156.1°
2034-12-11 Mon	89	—	unknown	21:20–03:55 (good, 6.58 h)	42.9° 00:35	11.46	1%	154.8°
2034-12-12 Tue	89	—	unknown	21:15–03:50 (good, 6.58 h)	42.9° 00:30	11.47	4%	148.8°
2034-12-13 Wed	89	—	unknown	21:15–03:45 (good, 6.5 h)	42.9° 00:25	11.48	9%	140.2°
2034-12-14 Thu	89	—	unknown	21:10–03:45 (good, 6.58 h)	42.9° 00:25	11.49	15%	130.1°
2034-12-15 Fri	89	—	unknown	21:05–03:40 (good, 6.58 h)	42.9° 00:20	11.49	22%	119.3°
2034-12-16 Sat	89	—	unknown	21:05–03:35 (good, 6.5 h)	42.9° 00:15	11.5	31%	107.9°
2034-12-17 Sun	89	—	unknown	21:10–03:30 (good, 6.33 h)	42.9° 00:10	11.5	41%	96.1°
2034-12-18 Mon	89	—	unknown	21:15–03:25 (good, 6.17 h)	42.9° 00:10	11.5	52%	83.9°
2034-12-19 Tue	86	—	unknown	21:35–03:25 (good, 5.83 h)	42.9° 00:05	11.51	63%	71.4°
2034-12-20 Wed	80	—	unknown	00:00–03:20 (good, 3.33 h)	42.9° 00:00	11.51	74%	58.8°
2034-12-21 Thu	43	—	unknown	20:45–03:45 (marginal, 7.0 h)	42.9° 23:55	11.51	83%	46.3°
2034-12-22 Fri	24	—	unknown	22:40–03:20 (marginal, 4.67 h)	42.9° 23:50	11.51	91%	34.7°
2034-12-23 Sat	14	—	unknown	—	42.9° 23:50	11.51	97%	26.0°
2034-12-24 Sun	10	—	unknown	—	42.9° 23:45	11.5	100%	24.0°
2034-12-25 Mon	13	—	unknown	—	42.9° 23:40	11.5	99%	30.1°
2034-12-26 Tue	25	—	unknown	20:10–00:50 (marginal, 4.67 h)	42.9° 23:35	11.5	96%	40.7°
2034-12-27 Wed	43	—	unknown	19:45–02:40 (marginal, 6.92 h)	42.9° 23:30	11.49	91%	52.7°
2034-12-28 Thu	81	—	unknown	20:15–23:15 (good, 3.0 h)	42.9° 23:30	11.48	83%	65.2°
2034-12-29 Fri	86	—	unknown	20:10–01:35 (good, 5.42 h)	42.9° 23:25	11.48	74%	77.5°
2034-12-30 Sat	88	—	unknown	20:05–02:15 (good, 6.17 h)	42.9° 23:20	11.47	65%	89.5°
2034-12-31 Sun	89	—	unknown	20:00–02:25 (good, 6.42 h)	42.9° 23:15	11.46	55%	101.1°
2035-01-01 Mon	89	—	unknown	20:00–02:25 (good, 6.42 h)	42.9° 23:15	11.45	45%	112.3°
2035-01-02 Tue	89	—	unknown	19:55–02:25 (good, 6.5 h)	42.9° 23:10	11.44	36%	123.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-12-04&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.