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.

2037-07-11astronomy score per night — click a bar for that night2037-08-09

night of	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-07-11 Sat	—	unknown	—	42.9° 11:35	4.85	2%	28.7°
2037-07-12 Sun	—	unknown	—	42.9° 11:30	4.89	0%	37.0°
2037-07-13 Mon	—	unknown	—	42.9° 11:30	4.93	1%	48.0°
2037-07-14 Tue	—	unknown	—	42.9° 11:25	4.97	5%	60.4°
2037-07-15 Wed	—	unknown	—	42.9° 11:20	5.01	11%	73.3°
2037-07-16 Thu	—	unknown	—	42.9° 11:15	5.06	19%	86.5°
2037-07-17 Fri	—	unknown	—	42.9° 11:10	5.1	29%	99.5°
2037-07-18 Sat	—	unknown	—	42.9° 11:10	5.15	40%	112.3°
2037-07-19 Sun	—	unknown	—	42.9° 11:05	5.19	52%	124.5°
2037-07-20 Mon	—	unknown	—	42.9° 11:00	5.24	63%	135.9°
2037-07-21 Tue	—	unknown	—	42.9° 10:55	5.29	73%	145.7°
2037-07-22 Wed	—	unknown	—	42.9° 10:55	5.34	82%	152.6°
2037-07-23 Thu	—	unknown	—	42.9° 10:50	5.39	90%	154.4°
2037-07-24 Fri	—	unknown	—	42.9° 10:45	5.44	95%	150.4°
2037-07-25 Sat	—	unknown	—	42.9° 10:40	5.49	98%	142.7°
2037-07-26 Sun	—	unknown	—	42.9° 10:35	5.54	100%	133.2°
2037-07-27 Mon	—	unknown	—	42.9° 10:35	5.6	99%	122.9°
2037-07-28 Tue	—	unknown	—	42.9° 10:30	5.65	97%	112.3°
2037-07-29 Wed	—	unknown	—	42.9° 10:25	5.7	93%	101.6°
2037-07-30 Thu	—	unknown	—	42.9° 10:20	5.76	87%	90.9°
2037-07-31 Fri	—	unknown	—	42.9° 10:15	5.81	80%	80.2°
2037-08-01 Sat	—	unknown	—	42.9° 10:15	5.87	72%	69.6°
2037-08-02 Sun	—	unknown	—	42.9° 10:10	5.92	63%	59.2°
2037-08-03 Mon	—	unknown	—	42.9° 10:05	5.98	54%	49.0°
2037-08-04 Tue	—	unknown	—	42.9° 10:00	6.03	44%	39.4°
2037-08-05 Wed	—	unknown	—	42.9° 10:00	6.09	34%	31.1°
2037-08-06 Thu	—	unknown	—	42.9° 09:55	6.15	25%	26.0°
2037-08-07 Fri	—	unknown	—	42.9° 09:50	6.2	16%	26.6°
2037-08-08 Sat	—	unknown	—	42.9° 09:45	6.26	9%	33.0°
2037-08-09 Sun	—	unknown	—	42.9° 09:40	6.32	3%	43.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-07-11&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.