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: 10-17 (89), 10-18 (89), 10-19 (89), 10-20 (89), 10-21 (89) — by astronomy; check the weather when the night is within four days.

2036-10-17astronomy score per night — click a bar for that night2036-11-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-10-17 Fri	89	—	unknown	01:55–06:05 (good, 4.17 h)	42.9° 05:10	9.93	3%	101.6°
2036-10-18 Sat	89	—	unknown	01:50–06:10 (good, 4.33 h)	42.9° 05:05	9.97	1%	114.5°
2036-10-19 Sun	89	—	unknown	01:45–06:10 (good, 4.42 h)	42.9° 05:00	10.02	0%	126.9°
2036-10-20 Mon	89	—	unknown	01:45–06:10 (good, 4.42 h)	42.9° 05:00	10.06	3%	138.2°
2036-10-21 Tue	89	—	unknown	01:40–06:10 (good, 4.5 h)	42.9° 04:55	10.1	7%	147.8°
2036-10-22 Wed	89	—	unknown	01:35–06:10 (good, 4.58 h)	42.9° 04:50	10.14	14%	154.0°
2036-10-23 Thu	89	—	unknown	01:30–06:15 (good, 4.75 h)	42.9° 04:45	10.18	21%	154.9°
2036-10-24 Fri	89	—	unknown	01:30–06:15 (good, 4.75 h)	42.9° 04:40	10.22	30%	150.3°
2036-10-25 Sat	89	—	unknown	01:25–05:15 (good, 4.83 h)	42.9° 03:40	10.26	39%	142.4°
2036-10-26 Sun	89	—	unknown	00:20–05:15 (good, 4.92 h)	42.9° 03:35	10.3	49%	133.1°
2036-10-27 Mon	89	—	unknown	00:15–05:20 (good, 5.08 h)	42.9° 03:30	10.34	58%	123.1°
2036-10-28 Tue	89	—	unknown	00:20–05:20 (good, 5.0 h)	42.9° 03:25	10.37	67%	112.7°
2036-10-29 Wed	89	—	unknown	00:25–05:20 (good, 4.92 h)	42.9° 03:20	10.41	76%	102.0°
2036-10-30 Thu	89	—	unknown	00:30–05:20 (good, 4.83 h)	42.9° 03:20	10.45	83%	91.0°
2036-10-31 Fri	88	—	unknown	01:20–05:20 (good, 4.0 h)	42.9° 03:15	10.49	90%	80.0°
2036-11-01 Sat	76	—	unknown	03:15–05:25 (good, 2.17 h)	42.9° 03:10	10.52	95%	68.7°
2036-11-02 Sun	40	—	unknown	00:00–05:25 (marginal, 5.42 h)	42.9° 03:05	10.56	98%	57.5°
2036-11-03 Mon	27	—	unknown	00:30–05:25 (marginal, 4.92 h)	42.9° 03:05	10.59	100%	46.5°
2036-11-04 Tue	17	—	unknown	03:10–05:25 (marginal, 2.25 h)	42.9° 03:00	10.63	99%	36.3°
2036-11-05 Wed	12	—	unknown	05:15–05:25 (marginal, 0.17 h)	42.9° 02:55	10.66	96%	28.2°
2036-11-06 Thu	13	—	unknown	—	42.9° 02:50	10.7	90%	24.8°
2036-11-07 Fri	20	—	unknown	23:35–05:30 (marginal, 5.92 h)	42.9° 02:45	10.73	83%	28.2°
2036-11-08 Sat	34	—	unknown	23:10–05:30 (marginal, 6.33 h)	42.9° 02:45	10.76	73%	36.6°
2036-11-09 Sun	53	—	unknown	22:55–05:30 (marginal, 6.58 h)	42.9° 02:40	10.79	63%	47.4°
2036-11-10 Mon	69	—	unknown	23:40–04:45 (good, 5.08 h)	42.9° 02:35	10.83	52%	59.4°
2036-11-11 Tue	84	—	unknown	23:15–05:30 (good, 6.25 h)	42.9° 02:30	10.86	40%	72.0°
2036-11-12 Wed	88	—	unknown	23:15–05:35 (good, 6.33 h)	42.9° 02:25	10.89	29%	84.7°
2036-11-13 Thu	89	—	unknown	23:10–05:35 (good, 6.42 h)	42.9° 02:25	10.92	20%	97.6°
2036-11-14 Fri	89	—	unknown	23:05–05:35 (good, 6.5 h)	42.9° 02:20	10.95	12%	110.2°
2036-11-15 Sat	89	—	unknown	23:00–05:35 (good, 6.58 h)	42.9° 02:15	10.98	5%	122.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-10-17&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.