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: 07-20 (1), 07-21 (1) — by astronomy; check the weather when the night is within four days.

2033-07-20astronomy score per night — click a bar for that night2033-08-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2033-07-20 Wed	1	—	unknown	—	50.2° 17:55	5.24	31%	134.5°
2033-07-21 Thu	1	—	unknown	—	50.2° 17:55	5.29	21%	120.9°
2033-07-22 Fri	0	—	unknown	—	50.2° 17:50	5.34	13%	107.4°
2033-07-23 Sat	0	—	unknown	—	50.2° 17:45	5.39	6%	94.0°
2033-07-24 Sun	0	—	unknown	—	50.2° 17:40	5.44	2%	80.9°
2033-07-25 Mon	0	—	unknown	—	50.2° 17:35	5.49	0%	68.0°
2033-07-26 Tue	0	—	unknown	—	50.2° 17:35	5.54	0%	55.4°
2033-07-27 Wed	0	—	unknown	—	50.2° 17:30	5.59	3%	43.0°
2033-07-28 Thu	0	—	unknown	—	50.2° 17:25	5.65	7%	30.9°
2033-07-29 Fri	0	—	unknown	—	50.2° 17:20	5.7	12%	19.1°
2033-07-30 Sat	0	—	unknown	—	50.2° 17:20	5.76	19%	8.4°
2033-07-31 Sun	0	—	unknown	—	50.2° 17:15	5.81	27%	7.7°
2033-08-01 Mon	0	—	unknown	—	50.2° 17:10	5.86	36%	18.1°
2033-08-02 Tue	0	—	unknown	—	50.2° 17:05	5.92	45%	29.7°
2033-08-03 Wed	0	—	unknown	—	50.2° 17:00	5.98	55%	41.5°
2033-08-04 Thu	0	—	unknown	—	50.2° 17:00	6.03	64%	53.7°
2033-08-05 Fri	0	—	unknown	—	50.2° 16:55	6.09	74%	66.2°
2033-08-06 Sat	0	—	unknown	—	50.2° 16:50	6.14	82%	79.0°
2033-08-07 Sun	0	—	unknown	—	50.2° 16:45	6.2	90%	92.3°
2033-08-08 Mon	0	—	unknown	—	50.2° 16:40	6.26	95%	105.9°
2033-08-09 Tue	0	—	unknown	—	50.2° 16:40	6.32	99%	120.0°
2033-08-10 Wed	0	—	unknown	—	50.2° 16:35	6.37	100%	134.3°
2033-08-11 Thu	0	—	unknown	—	50.2° 16:30	6.43	98%	148.8°
2033-08-12 Fri	0	—	unknown	—	50.2° 16:25	6.49	93%	163.2°
2033-08-13 Sat	0	—	unknown	—	50.2° 16:25	6.54	86%	174.4°
2033-08-14 Sun	0	—	unknown	—	50.2° 16:20	6.6	77%	165.5°
2033-08-15 Mon	0	—	unknown	—	50.2° 16:15	6.66	66%	151.6°
2033-08-16 Tue	0	—	unknown	—	50.2° 16:10	6.72	55%	137.7°
2033-08-17 Wed	0	—	unknown	—	50.2° 16:05	6.78	44%	123.9°
2033-08-18 Thu	0	—	unknown	—	50.2° 16:05	6.83	34%	110.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2033-07-20&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.