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: 10-23 (89), 10-24 (89), 10-25 (89), 10-26 (89), 10-27 (89) — by astronomy; check the weather when the night is within four days.

2030-10-15astronomy score per night — click a bar for that night2030-11-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-10-15 Tue	12	—	unknown	02:30–06:05 (marginal, 3.58 h)	42.9° 05:20	9.82	82%	30.0°
2030-10-16 Wed	17	—	unknown	02:00–06:05 (marginal, 4.08 h)	42.9° 05:15	9.87	75%	27.3°
2030-10-17 Thu	24	—	unknown	01:40–06:05 (marginal, 4.42 h)	42.9° 05:10	9.91	66%	29.0°
2030-10-18 Fri	36	—	unknown	01:25–06:05 (marginal, 4.67 h)	42.9° 05:05	9.95	57%	34.7°
2030-10-19 Sat	50	—	unknown	02:15–06:10 (good, 3.92 h)	42.9° 05:05	9.99	47%	42.8°
2030-10-20 Sun	65	—	unknown	02:00–06:10 (good, 4.17 h)	42.9° 05:00	10.03	37%	52.5°
2030-10-21 Mon	82	—	unknown	01:40–06:10 (good, 4.5 h)	42.9° 04:55	10.08	28%	63.1°
2030-10-22 Tue	87	—	unknown	01:40–06:10 (good, 4.5 h)	42.9° 04:50	10.12	19%	74.4°
2030-10-23 Wed	89	—	unknown	01:35–06:15 (good, 4.67 h)	42.9° 04:50	10.16	11%	86.3°
2030-10-24 Thu	89	—	unknown	01:30–06:15 (good, 4.75 h)	42.9° 04:45	10.2	5%	98.7°
2030-10-25 Fri	89	—	unknown	01:25–06:15 (good, 4.83 h)	42.9° 04:40	10.24	1%	111.3°
2030-10-26 Sat	89	—	unknown	01:20–05:15 (good, 4.92 h)	42.9° 03:35	10.28	0%	123.9°
2030-10-27 Sun	89	—	unknown	00:20–05:15 (good, 4.92 h)	42.9° 03:30	10.32	2%	135.8°
2030-10-28 Mon	89	—	unknown	00:15–05:20 (good, 5.08 h)	42.9° 03:30	10.35	6%	145.9°
2030-10-29 Tue	89	—	unknown	00:10–05:20 (good, 5.17 h)	42.9° 03:25	10.39	13%	152.1°
2030-10-30 Wed	89	—	unknown	00:05–05:20 (good, 5.25 h)	42.9° 03:20	10.43	22%	151.7°
2030-10-31 Thu	89	—	unknown	00:00–05:20 (good, 5.33 h)	42.9° 03:15	10.47	32%	145.3°
2030-11-01 Fri	89	—	unknown	00:00–05:20 (good, 5.33 h)	42.9° 03:10	10.5	44%	135.6°
2030-11-02 Sat	89	—	unknown	23:55–05:25 (good, 5.5 h)	42.9° 03:10	10.54	55%	124.6°
2030-11-03 Sun	89	—	unknown	00:00–05:25 (good, 5.42 h)	42.9° 03:05	10.57	65%	113.2°
2030-11-04 Mon	89	—	unknown	00:05–05:25 (good, 5.33 h)	42.9° 03:00	10.61	75%	101.7°
2030-11-05 Tue	89	—	unknown	00:15–05:25 (good, 5.17 h)	42.9° 02:55	10.64	83%	90.2°
2030-11-06 Wed	86	—	unknown	01:30–05:30 (good, 4.0 h)	42.9° 02:55	10.68	90%	79.0°
2030-11-07 Thu	73	—	unknown	04:00–05:30 (good, 1.5 h)	42.9° 02:50	10.71	95%	68.0°
2030-11-08 Fri	39	—	unknown	23:45–05:30 (marginal, 5.75 h)	42.9° 02:45	10.74	98%	57.5°
2030-11-09 Sat	26	—	unknown	00:40–05:30 (marginal, 4.83 h)	42.9° 02:40	10.78	100%	47.6°
2030-11-10 Sun	18	—	unknown	03:05–05:30 (marginal, 2.42 h)	42.9° 02:35	10.81	99%	38.7°
2030-11-11 Mon	12	—	unknown	—	42.9° 02:35	10.84	97%	31.5°
2030-11-12 Tue	12	—	unknown	—	42.9° 02:30	10.87	93%	27.5°
2030-11-13 Wed	17	—	unknown	23:30–01:30 (marginal, 2.0 h)	42.9° 02:25	10.9	88%	27.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-10-15&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.