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: 08-20 (1) — by astronomy; check the weather when the night is within four days.

2033-07-22astronomy score per night — click a bar for that night2033-08-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-07-22 Fri	0	—	unknown	—	42.9° 10:50	5.34	13%	24.5°
2033-07-23 Sat	0	—	unknown	—	42.9° 10:50	5.39	6%	25.4°
2033-07-24 Sun	0	—	unknown	—	42.9° 10:45	5.44	2%	31.8°
2033-07-25 Mon	0	—	unknown	—	42.9° 10:40	5.49	0%	41.2°
2033-07-26 Tue	0	—	unknown	—	42.9° 10:35	5.54	0%	51.7°
2033-07-27 Wed	0	—	unknown	—	42.9° 10:35	5.59	3%	62.6°
2033-07-28 Thu	0	—	unknown	—	42.9° 10:30	5.65	7%	73.6°
2033-07-29 Fri	0	—	unknown	—	42.9° 10:25	5.7	12%	84.6°
2033-07-30 Sat	0	—	unknown	—	42.9° 10:20	5.76	19%	95.5°
2033-07-31 Sun	0	—	unknown	—	42.9° 10:15	5.81	27%	106.3°
2033-08-01 Mon	0	—	unknown	—	42.9° 10:15	5.86	36%	117.0°
2033-08-02 Tue	0	—	unknown	—	42.9° 10:10	5.92	45%	127.4°
2033-08-03 Wed	0	—	unknown	—	42.9° 10:05	5.98	55%	137.4°
2033-08-04 Thu	0	—	unknown	—	42.9° 10:00	6.03	64%	146.6°
2033-08-05 Fri	0	—	unknown	—	42.9° 09:55	6.09	74%	153.6°
2033-08-06 Sat	0	—	unknown	—	42.9° 09:55	6.14	82%	156.1°
2033-08-07 Sun	0	—	unknown	—	42.9° 09:50	6.2	90%	152.2°
2033-08-08 Mon	0	—	unknown	—	42.9° 09:45	6.26	95%	143.5°
2033-08-09 Tue	0	—	unknown	—	42.9° 09:40	6.32	99%	132.3°
2033-08-10 Wed	0	—	unknown	—	42.9° 09:40	6.37	100%	119.8°
2033-08-11 Thu	0	—	unknown	—	42.9° 09:35	6.43	98%	106.6°
2033-08-12 Fri	0	—	unknown	—	42.9° 09:30	6.49	93%	93.2°
2033-08-13 Sat	0	—	unknown	—	42.9° 09:25	6.54	86%	79.7°
2033-08-14 Sun	0	—	unknown	—	42.9° 09:20	6.6	77%	66.4°
2033-08-15 Mon	0	—	unknown	—	42.9° 09:20	6.66	66%	53.7°
2033-08-16 Tue	0	—	unknown	—	42.9° 09:15	6.72	55%	41.9°
2033-08-17 Wed	0	—	unknown	—	42.9° 09:10	6.78	44%	31.8°
2033-08-18 Thu	0	—	unknown	—	42.9° 09:05	6.83	34%	25.1°
2033-08-19 Fri	0	—	unknown	—	42.9° 09:00	6.89	24%	24.4°
2033-08-20 Sat	1	—	unknown	—	42.9° 09:00	6.95	16%	29.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-07-22&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.