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: 11-11 (3), 11-09 (2), 11-10 (2), 11-04 (1), 11-05 (1) — by astronomy; check the weather when the night is within four days.

2047-10-13astronomy score per night — click a bar for that night2047-11-11

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-10-13 Sun	0	—	unknown	—	50.1° 12:25	9.73	33%	55.4°
2047-10-14 Mon	0	—	unknown	—	50.1° 12:20	9.77	23%	42.4°
2047-10-15 Tue	0	—	unknown	—	50.1° 12:15	9.82	14%	29.2°
2047-10-16 Wed	0	—	unknown	—	50.1° 12:15	9.86	7%	16.5°
2047-10-17 Thu	0	—	unknown	—	50.1° 12:10	9.9	2%	9.9°
2047-10-18 Fri	0	—	unknown	—	50.1° 12:05	9.95	0%	19.0°
2047-10-19 Sat	0	—	unknown	—	50.1° 12:00	9.99	1%	32.9°
2047-10-20 Sun	0	—	unknown	—	50.1° 11:55	10.03	5%	47.5°
2047-10-21 Mon	0	—	unknown	—	50.1° 11:50	10.07	11%	62.2°
2047-10-22 Tue	0	—	unknown	—	50.1° 11:45	10.11	20%	76.7°
2047-10-23 Wed	0	—	unknown	—	50.1° 11:40	10.15	30%	90.8°
2047-10-24 Thu	0	—	unknown	—	50.1° 11:40	10.19	40%	104.5°
2047-10-25 Fri	0	—	unknown	—	50.1° 11:35	10.23	51%	117.7°
2047-10-26 Sat	0	—	unknown	—	50.1° 10:30	10.27	62%	130.5°
2047-10-27 Sun	0	—	unknown	—	50.1° 10:25	10.31	71%	142.9°
2047-10-28 Mon	0	—	unknown	—	50.1° 10:20	10.35	80%	154.7°
2047-10-29 Tue	0	—	unknown	—	50.1° 10:20	10.39	87%	165.2°
2047-10-30 Wed	0	—	unknown	—	50.1° 10:15	10.42	93%	170.1°
2047-10-31 Thu	0	—	unknown	—	50.1° 10:10	10.46	97%	163.8°
2047-11-01 Fri	0	—	unknown	—	50.1° 10:05	10.5	99%	153.3°
2047-11-02 Sat	0	—	unknown	—	50.1° 10:05	10.53	100%	142.1°
2047-11-03 Sun	0	—	unknown	—	50.1° 10:00	10.57	99%	130.7°
2047-11-04 Mon	1	—	unknown	—	50.1° 09:55	10.61	96%	119.1°
2047-11-05 Tue	1	—	unknown	—	50.1° 09:50	10.64	91%	107.4°
2047-11-06 Wed	1	—	unknown	—	50.1° 09:45	10.67	85%	95.7°
2047-11-07 Thu	1	—	unknown	—	50.1° 09:45	10.71	77%	83.8°
2047-11-08 Fri	1	—	unknown	—	50.1° 09:40	10.74	69%	71.7°
2047-11-09 Sat	2	—	unknown	05:25–05:30 (marginal, 0.08 h)	50.1° 09:35	10.77	59%	59.4°
2047-11-10 Sun	2	—	unknown	05:20–05:30 (marginal, 0.17 h)	50.1° 09:30	10.81	49%	46.9°
2047-11-11 Mon	3	—	unknown	05:10–05:35 (marginal, 0.42 h)	50.1° 09:25	10.84	38%	34.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-10-13&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.