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: 10-18 (87), 10-17 (78), 10-03 (67), 10-04 (67), 10-02 (66) — by astronomy; check the weather when the night is within four days.

2033-09-19astronomy score per night — click a bar for that night2033-10-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-09-19 Mon	40	—	unknown	03:45–05:35 (good, 1.83 h)	42.9° 07:00	8.6	12%	56.6°
2033-09-20 Tue	44	—	unknown	03:40–05:35 (good, 1.92 h)	42.9° 06:55	8.65	6%	67.5°
2033-09-21 Wed	47	—	unknown	03:40–05:40 (good, 2.0 h)	42.9° 06:55	8.7	2%	78.4°
2033-09-22 Thu	48	—	unknown	03:35–05:40 (good, 2.08 h)	42.9° 06:50	8.75	0%	89.4°
2033-09-23 Fri	50	—	unknown	03:30–05:40 (good, 2.17 h)	42.9° 06:45	8.8	0%	100.2°
2033-09-24 Sat	52	—	unknown	03:25–05:40 (good, 2.25 h)	42.9° 06:40	8.85	2%	111.0°
2033-09-25 Sun	53	—	unknown	03:25–05:40 (good, 2.25 h)	42.9° 06:35	8.9	5%	121.6°
2033-09-26 Mon	55	—	unknown	03:20–05:45 (good, 2.42 h)	42.9° 06:35	8.95	10%	131.8°
2033-09-27 Tue	57	—	unknown	03:15–05:45 (good, 2.5 h)	42.9° 06:30	9.0	16%	141.4°
2033-09-28 Wed	59	—	unknown	03:10–05:45 (good, 2.58 h)	42.9° 06:25	9.05	24%	149.8°
2033-09-29 Thu	60	—	unknown	03:05–05:45 (good, 2.67 h)	42.9° 06:20	9.1	32%	155.3°
2033-09-30 Fri	63	—	unknown	03:05–05:50 (good, 2.75 h)	42.9° 06:15	9.15	42%	155.8°
2033-10-01 Sat	64	—	unknown	03:00–05:50 (good, 2.83 h)	42.9° 06:15	9.19	52%	150.6°
2033-10-02 Sun	66	—	unknown	02:55–05:50 (good, 2.92 h)	42.9° 06:10	9.24	63%	141.6°
2033-10-03 Mon	67	—	unknown	02:50–05:50 (good, 3.0 h)	42.9° 06:05	9.29	73%	130.6°
2033-10-04 Tue	67	—	unknown	02:55–05:50 (good, 2.92 h)	42.9° 06:00	9.34	83%	118.3°
2033-10-05 Wed	65	—	unknown	03:00–05:55 (good, 2.92 h)	42.9° 06:00	9.38	91%	105.2°
2033-10-06 Thu	58	—	unknown	03:15–05:55 (good, 2.67 h)	42.9° 05:55	9.43	96%	91.6°
2033-10-07 Fri	35	—	unknown	05:00–05:55 (good, 0.92 h)	42.9° 05:50	9.48	100%	77.7°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-09-19&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.