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: 11-05 (1), 11-06 (1), 11-07 (1), 11-08 (1) — by astronomy; check the weather when the night is within four days.

2039-10-10astronomy score per night — click a bar for that night2039-11-08

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-10-10 Mon	0	—	unknown	—	50.1° 12:35	9.59	45%	72.2°
2039-10-11 Tue	0	—	unknown	—	50.1° 12:35	9.64	35%	60.0°
2039-10-12 Wed	0	—	unknown	—	50.1° 12:30	9.68	26%	47.6°
2039-10-13 Thu	0	—	unknown	—	50.1° 12:25	9.73	18%	34.8°
2039-10-14 Fri	0	—	unknown	—	50.1° 12:20	9.77	10%	21.7°
2039-10-15 Sat	0	—	unknown	—	50.1° 12:15	9.81	5%	8.1°
2039-10-16 Sun	0	—	unknown	—	50.1° 12:15	9.86	1%	5.8°
2039-10-17 Mon	0	—	unknown	—	50.1° 12:10	9.9	0%	20.1°
2039-10-18 Tue	0	—	unknown	—	50.1° 12:05	9.94	2%	34.7°
2039-10-19 Wed	0	—	unknown	—	50.1° 12:00	9.99	6%	49.4°
2039-10-20 Thu	0	—	unknown	—	50.1° 11:55	10.03	13%	64.1°
2039-10-21 Fri	0	—	unknown	—	50.1° 11:50	10.07	22%	78.7°
2039-10-22 Sat	0	—	unknown	—	50.1° 11:45	10.11	32%	93.1°
2039-10-23 Sun	0	—	unknown	—	50.1° 11:40	10.15	44%	107.3°
2039-10-24 Mon	0	—	unknown	—	50.1° 11:40	10.19	55%	121.2°
2039-10-25 Tue	0	—	unknown	—	50.1° 11:35	10.23	66%	134.8°
2039-10-26 Wed	0	—	unknown	—	50.1° 11:30	10.27	75%	148.3°
2039-10-27 Thu	0	—	unknown	—	50.1° 11:25	10.31	84%	161.4°
2039-10-28 Fri	0	—	unknown	—	50.1° 11:20	10.35	91%	174.4°
2039-10-29 Sat	0	—	unknown	—	50.1° 10:20	10.38	96%	172.8°
2039-10-30 Sun	0	—	unknown	—	50.1° 10:15	10.42	99%	160.2°
2039-10-31 Mon	0	—	unknown	—	50.1° 10:10	10.46	100%	147.8°
2039-11-01 Tue	0	—	unknown	—	50.1° 10:05	10.5	99%	135.6°
2039-11-02 Wed	0	—	unknown	—	50.1° 10:00	10.53	96%	123.5°
2039-11-03 Thu	0	—	unknown	—	50.1° 10:00	10.57	92%	111.6°
2039-11-04 Fri	0	—	unknown	—	50.1° 09:55	10.6	86%	99.7°
2039-11-05 Sat	1	—	unknown	—	50.1° 09:50	10.64	79%	87.9°
2039-11-06 Sun	1	—	unknown	—	50.1° 09:45	10.67	71%	76.0°
2039-11-07 Mon	1	—	unknown	—	50.1° 09:45	10.71	62%	64.1°
2039-11-08 Tue	1	—	unknown	—	50.1° 09:40	10.74	52%	52.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-10-10&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.