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: 11-23 (89), 11-24 (89), 11-25 (89), 11-26 (89), 11-27 (89) — by astronomy; check the weather when the night is within four days.

2035-11-21astronomy score per night — click a bar for that night2035-12-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-11-21 Wed	81	—	unknown	22:40–04:30 (good, 5.83 h)	42.9° 01:55	11.11	53%	66.0°
2035-11-22 Thu	86	—	unknown	22:35–04:50 (good, 6.25 h)	42.9° 01:50	11.14	42%	78.4°
2035-11-23 Fri	89	—	unknown	22:35–04:55 (good, 6.33 h)	42.9° 01:45	11.16	32%	90.6°
2035-11-24 Sat	89	—	unknown	22:30–05:00 (good, 6.5 h)	42.9° 01:45	11.19	22%	102.6°
2035-11-25 Sun	89	—	unknown	22:25–04:55 (good, 6.5 h)	42.9° 01:40	11.21	15%	114.3°
2035-11-26 Mon	89	—	unknown	22:20–04:55 (good, 6.58 h)	42.9° 01:35	11.23	8%	125.5°
2035-11-27 Tue	89	—	unknown	22:15–04:50 (good, 6.58 h)	42.9° 01:30	11.25	4%	136.1°
2035-11-28 Wed	89	—	unknown	22:15–04:45 (good, 6.5 h)	42.9° 01:25	11.27	1%	145.4°
2035-11-29 Thu	89	—	unknown	22:10–04:45 (good, 6.58 h)	42.9° 01:25	11.29	0%	152.7°
2035-11-30 Fri	89	—	unknown	22:05–04:40 (good, 6.58 h)	42.9° 01:20	11.31	1%	155.9°
2035-12-01 Sat	89	—	unknown	22:00–04:35 (good, 6.58 h)	42.9° 01:15	11.33	4%	153.8°
2035-12-02 Sun	89	—	unknown	21:55–04:30 (good, 6.58 h)	42.9° 01:10	11.34	9%	147.5°
2035-12-03 Mon	89	—	unknown	21:55–04:25 (good, 6.5 h)	42.9° 01:10	11.36	15%	139.0°
2035-12-04 Tue	89	—	unknown	21:50–04:25 (good, 6.58 h)	42.9° 01:05	11.38	22%	129.3°
2035-12-05 Wed	89	—	unknown	21:50–04:20 (good, 6.5 h)	42.9° 01:00	11.39	30%	118.9°
2035-12-06 Thu	89	—	unknown	21:45–04:15 (good, 6.5 h)	42.9° 00:55	11.4	39%	108.2°
2035-12-07 Fri	89	—	unknown	21:50–04:10 (good, 6.33 h)	42.9° 00:50	11.42	49%	97.0°
2035-12-08 Sat	89	—	unknown	21:55–04:05 (good, 6.17 h)	42.9° 00:50	11.43	59%	85.6°
2035-12-09 Sun	87	—	unknown	22:20–04:05 (good, 5.75 h)	42.9° 00:45	11.44	69%	73.8°
2035-12-10 Mon	82	—	unknown	00:30–04:00 (good, 3.5 h)	42.9° 00:40	11.45	78%	61.7°
2035-12-11 Tue	46	—	unknown	21:25–04:25 (marginal, 7.0 h)	42.9° 00:35	11.46	87%	49.7°
2035-12-12 Wed	26	—	unknown	22:50–04:05 (marginal, 5.25 h)	42.9° 00:30	11.47	93%	38.1°
2035-12-13 Thu	14	—	unknown	02:50–03:20 (marginal, 0.5 h)	42.9° 00:30	11.48	98%	28.5°
2035-12-14 Fri	10	—	unknown	—	42.9° 00:25	11.48	100%	24.1°
2035-12-15 Sat	12	—	unknown	—	42.9° 00:20	11.49	99%	27.9°
2035-12-16 Sun	22	—	unknown	21:00–00:55 (marginal, 3.92 h)	42.9° 00:15	11.5	94%	37.5°
2035-12-17 Mon	40	—	unknown	20:35–03:20 (marginal, 6.75 h)	42.9° 00:15	11.5	88%	49.5°
2035-12-18 Tue	71	—	unknown	21:25–23:35 (good, 2.17 h)	42.9° 00:10	11.5	79%	62.3°
2035-12-19 Wed	85	—	unknown	20:50–02:20 (good, 5.5 h)	42.9° 00:05	11.51	69%	75.2°
2035-12-20 Thu	88	—	unknown	20:45–03:00 (good, 6.25 h)	42.9° 00:00	11.51	58%	87.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-11-21&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.