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: 10-20 (89), 10-21 (89), 10-22 (89), 10-23 (89), 11-06 (89) — by astronomy; check the weather when the night is within four days.

2034-10-20astronomy score per night — click a bar for that night2034-11-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2034-11-01 Wed	42	—	unknown	23:30–05:20 (marginal, 5.83 h)	42.9° 03:10	10.5	63%	38.2°
2034-11-02 Thu	61	—	unknown	00:20–04:20 (good, 4.0 h)	42.9° 03:10	10.54	52%	49.3°
2034-11-03 Fri	79	—	unknown	23:50–05:25 (good, 5.58 h)	42.9° 03:05	10.58	42%	60.9°
2034-11-04 Sat	85	—	unknown	23:45–05:25 (good, 5.67 h)	42.9° 03:00	10.61	32%	72.6°
2034-11-05 Sun	88	—	unknown	23:45–05:25 (good, 5.67 h)	42.9° 02:55	10.64	23%	84.1°
2034-11-06 Mon	89	—	unknown	23:40–05:30 (good, 5.83 h)	42.9° 02:55	10.68	15%	95.5°
2034-11-07 Tue	89	—	unknown	23:35–05:30 (good, 5.92 h)	42.9° 02:50	10.71	9%	106.7°
2034-11-08 Wed	89	—	unknown	23:30–05:30 (good, 6.0 h)	42.9° 02:45	10.75	4%	117.6°
2034-11-09 Thu	89	—	unknown	23:25–05:30 (good, 6.08 h)	42.9° 02:40	10.78	1%	128.1°
2034-11-10 Fri	89	—	unknown	23:25–05:30 (good, 6.08 h)	42.9° 02:35	10.81	0%	138.1°
2034-11-11 Sat	89	—	unknown	23:20–05:35 (good, 6.25 h)	42.9° 02:35	10.84	1%	146.9°
2034-11-12 Sun	89	—	unknown	23:15–05:35 (good, 6.33 h)	42.9° 02:30	10.87	3%	153.6°
2034-11-13 Mon	89	—	unknown	23:10–05:35 (good, 6.42 h)	42.9° 02:25	10.9	7%	156.4°
2034-11-14 Tue	89	—	unknown	23:05–05:35 (good, 6.5 h)	42.9° 02:20	10.93	13%	153.8°
2034-11-15 Wed	89	—	unknown	23:05–05:35 (good, 6.5 h)	42.9° 02:15	10.96	20%	147.1°
2034-11-16 Thu	89	—	unknown	23:00–05:35 (good, 6.58 h)	42.9° 02:15	10.99	28%	138.0°
2034-11-17 Fri	89	—	unknown	22:55–05:30 (good, 6.58 h)	42.9° 02:10	11.02	38%	127.7°
2034-11-18 Sat	89	—	unknown	22:55–05:25 (good, 6.5 h)	42.9° 02:05	11.04	47%	116.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-10-20&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.