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.

2034-10-02astronomy score per night — click a bar for that night2034-10-31

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-10-02 Mon	14	—	unknown	02:55–05:50 (marginal, 2.92 h)	42.9° 06:10	9.23	70%	24.5°
2034-10-03 Tue	21	—	unknown	02:35–05:50 (marginal, 3.25 h)	42.9° 06:05	9.28	59%	24.4°
2034-10-04 Wed	31	—	unknown	02:20–05:50 (marginal, 3.5 h)	42.9° 06:05	9.33	48%	30.9°
2034-10-05 Thu	43	—	unknown	03:05–05:55 (good, 2.83 h)	42.9° 06:00	9.37	37%	40.9°
2034-10-06 Fri	55	—	unknown	02:50–05:55 (good, 3.08 h)	42.9° 05:55	9.42	27%	52.0°
2034-10-07 Sat	65	—	unknown	02:35–05:55 (good, 3.33 h)	42.9° 05:50	9.47	18%	63.6°
2034-10-08 Sun	72	—	unknown	02:35–05:55 (good, 3.33 h)	42.9° 05:45	9.51	11%	75.2°
2034-10-09 Mon	76	—	unknown	02:30–06:00 (good, 3.5 h)	42.9° 05:45	9.56	6%	86.8°
2034-10-10 Tue	78	—	unknown	02:25–06:00 (good, 3.58 h)	42.9° 05:40	9.6	2%	98.3°
2034-10-11 Wed	80	—	unknown	02:20–06:00 (good, 3.67 h)	42.9° 05:35	9.65	0%	109.5°
2034-10-12 Thu	82	—	unknown	02:15–06:00 (good, 3.75 h)	42.9° 05:30	9.69	0%	120.4°
2034-10-13 Fri	83	—	unknown	02:15–06:00 (good, 3.75 h)	42.9° 05:25	9.74	2%	130.9°
2034-10-14 Sat	85	—	unknown	02:10–06:05 (good, 3.92 h)	42.9° 05:25	9.78	6%	140.6°
2034-10-15 Sun	86	—	unknown	02:05–06:05 (good, 4.0 h)	42.9° 05:20	9.82	12%	149.1°
2034-10-16 Mon	88	—	unknown	02:00–06:05 (good, 4.08 h)	42.9° 05:15	9.87	18%	155.0°
2034-10-17 Tue	89	—	unknown	01:55–06:05 (good, 4.17 h)	42.9° 05:10	9.91	26%	156.4°
2034-10-18 Wed	89	—	unknown	01:55–06:05 (good, 4.17 h)	42.9° 05:10	9.95	35%	152.5°
2034-10-19 Thu	89	—	unknown	01:50–06:10 (good, 4.33 h)	42.9° 05:05	9.99	44%	144.9°
2034-10-20 Fri	89	—	unknown	01:45–06:10 (good, 4.42 h)	42.9° 05:00	10.04	54%	135.3°
2034-10-21 Sat	89	—	unknown	01:40–06:10 (good, 4.5 h)	42.9° 04:55	10.08	64%	124.4°
2034-10-22 Sun	89	—	unknown	01:45–06:10 (good, 4.42 h)	42.9° 04:50	10.12	74%	112.8°
2034-10-23 Mon	89	—	unknown	01:55–06:15 (good, 4.33 h)	42.9° 04:50	10.16	83%	100.4°
2034-10-24 Tue	85	—	unknown	02:15–06:15 (good, 4.0 h)	42.9° 04:45	10.2	90%	87.5°
2034-10-25 Wed	70	—	unknown	04:05–06:15 (good, 2.17 h)	42.9° 04:40	10.24	96%	74.3°
2034-10-26 Thu	37	—	unknown	01:25–06:15 (marginal, 4.83 h)	42.9° 04:35	10.28	99%	60.9°
2034-10-27 Fri	23	—	unknown	01:50–06:15 (marginal, 4.42 h)	42.9° 04:30	10.32	100%	47.8°
2034-10-28 Sat	14	—	unknown	03:35–05:20 (marginal, 1.75 h)	42.9° 03:30	10.35	97%	35.7°
2034-10-29 Sun	12	—	unknown	05:00–05:20 (marginal, 0.33 h)	42.9° 03:25	10.39	91%	26.5°
2034-10-30 Mon	16	—	unknown	00:20–05:20 (marginal, 5.0 h)	42.9° 03:20	10.43	84%	23.6°
2034-10-31 Tue	25	—	unknown	23:50–05:20 (marginal, 5.5 h)	42.9° 03:15	10.47	74%	28.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-10-02&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.