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 3C 273: 07-14 (2), 07-15 (1), 07-16 (1), 07-17 (1) — by astronomy; check the weather when the night is within four days.

2037-07-14astronomy score per night — click a bar for that night2037-08-12

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2037-07-14 Tue	2	—	unknown	22:10–22:15 (marginal, 0.08 h)	50.2° 18:20	4.97	5%	48.3°
2037-07-15 Wed	1	—	unknown	—	50.2° 18:15	5.01	11%	33.7°
2037-07-16 Thu	1	—	unknown	—	50.1° 18:15	5.06	19%	19.1°
2037-07-17 Fri	1	—	unknown	—	50.2° 18:10	5.1	29%	4.6°
2037-07-18 Sat	0	—	unknown	—	50.2° 18:05	5.15	40%	9.7°
2037-07-19 Sun	0	—	unknown	—	50.2° 18:00	5.19	52%	23.8°
2037-07-20 Mon	0	—	unknown	—	50.1° 17:55	5.24	63%	37.6°
2037-07-21 Tue	0	—	unknown	—	50.2° 17:55	5.29	73%	51.1°
2037-07-22 Wed	0	—	unknown	—	50.2° 17:50	5.34	82%	64.4°
2037-07-23 Thu	0	—	unknown	—	50.2° 17:45	5.39	90%	77.5°
2037-07-24 Fri	0	—	unknown	—	50.2° 17:40	5.44	95%	90.4°
2037-07-25 Sat	0	—	unknown	—	50.1° 17:35	5.49	98%	103.1°
2037-07-26 Sun	0	—	unknown	—	50.2° 17:35	5.54	100%	115.6°
2037-07-27 Mon	0	—	unknown	—	50.2° 17:30	5.6	99%	127.9°
2037-07-28 Tue	0	—	unknown	—	50.2° 17:25	5.65	97%	140.0°
2037-07-29 Wed	0	—	unknown	—	50.2° 17:20	5.7	93%	152.0°
2037-07-30 Thu	0	—	unknown	—	50.1° 17:20	5.76	87%	163.9°
2037-07-31 Fri	0	—	unknown	—	50.2° 17:15	5.81	80%	175.7°
2037-08-01 Sat	0	—	unknown	—	50.2° 17:10	5.87	72%	172.5°
2037-08-02 Sun	0	—	unknown	—	50.2° 17:05	5.92	63%	160.5°
2037-08-03 Mon	0	—	unknown	—	50.1° 17:00	5.98	54%	148.5°
2037-08-04 Tue	0	—	unknown	—	50.1° 17:00	6.03	44%	136.2°
2037-08-05 Wed	0	—	unknown	—	50.2° 16:55	6.09	34%	123.6°
2037-08-06 Thu	0	—	unknown	—	50.2° 16:50	6.15	25%	110.6°
2037-08-07 Fri	0	—	unknown	—	50.2° 16:45	6.2	16%	97.2°
2037-08-08 Sat	0	—	unknown	—	50.1° 16:40	6.26	9%	83.4°
2037-08-09 Sun	0	—	unknown	—	50.2° 16:40	6.32	3%	69.0°
2037-08-10 Mon	0	—	unknown	—	50.2° 16:35	6.37	0%	54.4°
2037-08-11 Tue	0	—	unknown	—	50.2° 16:30	6.43	0%	39.4°
2037-08-12 Wed	0	—	unknown	—	50.1° 16:25	6.49	3%	24.4°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2037-07-14&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.