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: 04-10 (1), 04-11 (1), 04-12 (1), 04-13 (1) — by astronomy; check the weather when the night is within four days.

2032-04-10astronomy score per night — click a bar for that night2032-05-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2032-04-10 Sat	1	—	unknown	—	42.9° 17:40	7.55	1%	56.6°
2032-04-11 Sun	1	—	unknown	—	42.9° 17:35	7.49	4%	45.0°
2032-04-12 Mon	1	—	unknown	—	42.9° 17:35	7.43	10%	35.0°
2032-04-13 Tue	1	—	unknown	—	42.9° 17:30	7.38	16%	27.7°
2032-04-14 Wed	0	—	unknown	—	42.9° 17:25	7.32	25%	25.0°
2032-04-15 Thu	0	—	unknown	—	42.9° 17:20	7.26	34%	27.9°
2032-04-16 Fri	0	—	unknown	—	42.9° 17:15	7.2	43%	34.7°
2032-04-17 Sat	0	—	unknown	—	42.9° 17:15	7.15	53%	43.4°
2032-04-18 Sun	0	—	unknown	—	42.9° 17:10	7.09	62%	53.2°
2032-04-19 Mon	0	—	unknown	—	42.9° 17:05	7.03	71%	63.4°
2032-04-20 Tue	0	—	unknown	—	42.9° 17:00	6.97	79%	74.0°
2032-04-21 Wed	0	—	unknown	—	42.9° 16:55	6.91	86%	84.9°
2032-04-22 Thu	0	—	unknown	—	42.9° 16:55	6.86	92%	96.0°
2032-04-23 Fri	0	—	unknown	—	42.9° 16:50	6.8	97%	107.3°
2032-04-24 Sat	0	—	unknown	—	42.9° 16:45	6.74	100%	118.6°
2032-04-25 Sun	0	—	unknown	—	42.9° 16:40	6.68	100%	129.8°
2032-04-26 Mon	0	—	unknown	—	42.9° 16:35	6.62	98%	140.4°
2032-04-27 Tue	0	—	unknown	—	42.9° 16:35	6.56	94%	149.4°
2032-04-28 Wed	0	—	unknown	—	42.9° 16:30	6.51	88%	154.6°
2032-04-29 Thu	0	—	unknown	—	42.9° 16:25	6.45	79%	153.4°
2032-04-30 Fri	0	—	unknown	—	42.9° 16:20	6.39	69%	146.3°
2032-05-01 Sat	0	—	unknown	—	42.9° 16:20	6.33	58%	136.1°
2032-05-02 Sun	0	—	unknown	—	42.9° 16:15	6.27	47%	124.3°
2032-05-03 Mon	0	—	unknown	—	42.9° 16:10	6.22	36%	111.8°
2032-05-04 Tue	0	—	unknown	—	42.9° 16:05	6.16	25%	99.1°
2032-05-05 Wed	0	—	unknown	—	42.9° 16:00	6.1	16%	86.2°
2032-05-06 Thu	0	—	unknown	—	42.9° 16:00	6.04	8%	73.5°
2032-05-07 Fri	0	—	unknown	—	42.9° 15:55	5.99	3%	61.1°
2032-05-08 Sat	0	—	unknown	—	42.9° 15:50	5.93	0%	49.3°
2032-05-09 Sun	0	—	unknown	—	42.9° 15:45	5.88	0%	38.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2032-04-10&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.