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: 10-27 (89), 10-28 (89), 10-29 (89), 10-30 (89), 10-31 (89) — by astronomy; check the weather when the night is within four days.

2035-10-15astronomy score per night — click a bar for that night2035-11-13

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2035-10-15 Mon	44	—	unknown	04:30–06:05 (good, 1.58 h)	42.9° 05:20	9.81	98%	76.2°
2035-10-16 Tue	32	—	unknown	02:00–06:05 (marginal, 4.08 h)	42.9° 05:15	9.86	100%	63.8°
2035-10-17 Wed	21	—	unknown	02:20–06:05 (marginal, 3.75 h)	42.9° 05:10	9.9	99%	51.5°
2035-10-18 Thu	14	—	unknown	03:40–06:05 (marginal, 2.42 h)	42.9° 05:10	9.94	96%	39.8°
2035-10-19 Fri	11	—	unknown	05:20–06:10 (marginal, 0.83 h)	42.9° 05:05	9.98	90%	29.9°
2035-10-20 Sat	14	—	unknown	02:05–06:10 (marginal, 4.08 h)	42.9° 05:00	10.03	82%	24.2°
2035-10-21 Sun	22	—	unknown	01:35–06:10 (marginal, 4.58 h)	42.9° 04:55	10.07	72%	25.8°
2035-10-22 Mon	34	—	unknown	01:15–06:10 (marginal, 4.92 h)	42.9° 04:55	10.11	61%	33.7°
2035-10-23 Tue	51	—	unknown	02:05–05:45 (good, 3.67 h)	42.9° 04:50	10.15	50%	44.4°
2035-10-24 Wed	70	—	unknown	01:45–06:15 (good, 4.5 h)	42.9° 04:45	10.19	38%	56.3°
2035-10-25 Thu	83	—	unknown	01:25–06:15 (good, 4.83 h)	42.9° 04:40	10.23	28%	68.6°
2035-10-26 Fri	87	—	unknown	01:25–06:15 (good, 4.83 h)	42.9° 04:35	10.27	19%	81.0°
2035-10-27 Sat	89	—	unknown	01:20–05:15 (good, 4.92 h)	42.9° 03:35	10.31	11%	93.3°
2035-10-28 Sun	89	—	unknown	00:15–05:20 (good, 5.08 h)	42.9° 03:30	10.35	5%	105.4°
2035-10-29 Mon	89	—	unknown	00:10–05:20 (good, 5.17 h)	42.9° 03:25	10.38	2%	117.2°
2035-10-30 Tue	89	—	unknown	00:05–05:20 (good, 5.25 h)	42.9° 03:20	10.42	0%	128.4°
2035-10-31 Wed	89	—	unknown	00:05–05:20 (good, 5.25 h)	42.9° 03:15	10.46	1%	138.9°
2035-11-01 Thu	89	—	unknown	00:00–05:20 (good, 5.33 h)	42.9° 03:15	10.49	3%	147.9°
2035-11-02 Fri	89	—	unknown	23:55–05:25 (good, 5.5 h)	42.9° 03:10	10.53	8%	154.2°
2035-11-03 Sat	89	—	unknown	23:50–05:25 (good, 5.58 h)	42.9° 03:05	10.57	14%	156.0°
2035-11-04 Sun	89	—	unknown	23:50–05:25 (good, 5.58 h)	42.9° 03:00	10.6	21%	152.5°
2035-11-05 Mon	89	—	unknown	23:45–05:25 (good, 5.67 h)	42.9° 03:00	10.64	29%	145.3°
2035-11-06 Tue	89	—	unknown	23:40–05:30 (good, 5.83 h)	42.9° 02:55	10.67	38%	136.3°
2035-11-07 Wed	89	—	unknown	23:35–05:30 (good, 5.92 h)	42.9° 02:50	10.7	47%	126.4°
2035-11-08 Thu	89	—	unknown	23:40–05:30 (good, 5.83 h)	42.9° 02:45	10.74	56%	115.7°
2035-11-09 Fri	89	—	unknown	23:40–05:30 (good, 5.83 h)	42.9° 02:40	10.77	66%	104.6°
2035-11-10 Sat	89	—	unknown	23:45–05:30 (good, 5.75 h)	42.9° 02:40	10.8	75%	93.1°
2035-11-11 Sun	88	—	unknown	00:20–05:35 (good, 5.25 h)	42.9° 02:35	10.83	84%	81.2°
2035-11-12 Mon	85	—	unknown	02:15–05:35 (good, 3.33 h)	42.9° 02:30	10.86	91%	69.0°
2035-11-13 Tue	62	—	unknown	05:20–05:35 (good, 0.25 h)	42.9° 02:25	10.89	96%	56.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2035-10-15&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.