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: 10-19 (89), 10-20 (89), 10-21 (89), 10-22 (89), 10-23 (89) — by astronomy; check the weather when the night is within four days.

2033-10-08astronomy score per night — click a bar for that night2033-11-06

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-10-08 Sat	25	—	unknown	02:30–05:55 (marginal, 3.42 h)	42.9° 05:45	9.52	100%	63.9°
2033-10-09 Sun	17	—	unknown	02:50–06:00 (marginal, 3.17 h)	42.9° 05:40	9.57	97%	50.5°
2033-10-10 Mon	12	—	unknown	03:30–06:00 (marginal, 2.5 h)	42.9° 05:40	9.61	91%	38.3°
2033-10-11 Tue	12	—	unknown	02:50–06:00 (marginal, 3.17 h)	42.9° 05:35	9.66	83%	28.5°
2033-10-12 Wed	16	—	unknown	02:15–06:00 (marginal, 3.75 h)	42.9° 05:30	9.7	74%	23.8°
2033-10-13 Thu	25	—	unknown	01:55–06:00 (marginal, 4.08 h)	42.9° 05:25	9.75	63%	26.1°
2033-10-14 Fri	36	—	unknown	01:40–06:05 (marginal, 4.42 h)	42.9° 05:20	9.79	53%	33.7°
2033-10-15 Sat	50	—	unknown	02:25–06:05 (good, 3.67 h)	42.9° 05:20	9.83	43%	43.4°
2033-10-16 Sun	65	—	unknown	02:10–06:05 (good, 3.92 h)	42.9° 05:15	9.88	33%	54.0°
2033-10-17 Mon	78	—	unknown	01:55–06:05 (good, 4.17 h)	42.9° 05:10	9.92	24%	64.8°
2033-10-18 Tue	87	—	unknown	01:50–06:10 (good, 4.33 h)	42.9° 05:05	9.96	16%	75.7°
2033-10-19 Wed	89	—	unknown	01:50–06:10 (good, 4.33 h)	42.9° 05:05	10.0	10%	86.6°
2033-10-20 Thu	89	—	unknown	01:45–06:10 (good, 4.42 h)	42.9° 05:00	10.05	5%	97.5°
2033-10-21 Fri	89	—	unknown	01:40–06:10 (good, 4.5 h)	42.9° 04:55	10.09	2%	108.2°
2033-10-22 Sat	89	—	unknown	01:35–06:10 (good, 4.58 h)	42.9° 04:50	10.13	0%	118.9°
2033-10-23 Sun	89	—	unknown	01:35–06:15 (good, 4.67 h)	42.9° 04:45	10.17	0%	129.2°
2033-10-24 Mon	89	—	unknown	01:30–06:15 (good, 4.75 h)	42.9° 04:45	10.21	2%	139.1°
2033-10-25 Tue	89	—	unknown	01:25–06:15 (good, 4.83 h)	42.9° 04:40	10.25	6%	147.9°
2033-10-26 Wed	89	—	unknown	01:20–06:15 (good, 4.92 h)	42.9° 04:35	10.29	12%	154.3°
2033-10-27 Thu	89	—	unknown	01:15–06:15 (good, 5.0 h)	42.9° 04:30	10.33	19%	156.2°
2033-10-28 Fri	89	—	unknown	01:15–06:20 (good, 5.08 h)	42.9° 04:25	10.36	27%	152.4°
2033-10-29 Sat	89	—	unknown	01:10–05:20 (good, 5.17 h)	42.9° 03:25	10.4	37%	144.4°
2033-10-30 Sun	89	—	unknown	00:05–05:20 (good, 5.25 h)	42.9° 03:20	10.44	47%	134.2°
2033-10-31 Mon	89	—	unknown	00:05–05:20 (good, 5.25 h)	42.9° 03:15	10.48	58%	122.6°
2033-11-01 Tue	89	—	unknown	00:10–05:25 (good, 5.25 h)	42.9° 03:10	10.51	69%	110.3°
2033-11-02 Wed	89	—	unknown	00:15–05:25 (good, 5.17 h)	42.9° 03:10	10.55	79%	97.3°
2033-11-03 Thu	88	—	unknown	00:50–05:25 (good, 4.58 h)	42.9° 03:05	10.58	88%	83.9°
2033-11-04 Fri	78	—	unknown	03:05–05:25 (good, 2.33 h)	42.9° 03:00	10.62	94%	70.3°
2033-11-05 Sat	39	—	unknown	23:55–05:25 (marginal, 5.5 h)	42.9° 02:55	10.65	99%	56.7°
2033-11-06 Sun	24	—	unknown	01:20–05:30 (marginal, 4.17 h)	42.9° 02:50	10.69	100%	43.9°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-10-08&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.