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: 11-15 (11), 11-14 (9), 11-13 (7), 11-12 (6), 11-11 (4) — by astronomy; check the weather when the night is within four days.

2039-10-17astronomy score per night — click a bar for that night2039-11-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
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°
2039-11-09 Wed	2	—	unknown	05:20–05:30 (marginal, 0.17 h)	50.1° 09:35	10.77	42%	39.6°
2039-11-10 Thu	3	—	unknown	05:15–05:30 (marginal, 0.25 h)	50.1° 09:30	10.8	33%	26.9°
2039-11-11 Fri	4	—	unknown	05:10–05:35 (marginal, 0.42 h)	50.1° 09:25	10.83	23%	13.8°
2039-11-12 Sat	6	—	unknown	05:10–05:35 (marginal, 0.42 h)	50.1° 09:25	10.87	15%	0.3°
2039-11-13 Sun	7	—	unknown	05:05–06:10 (marginal, 1.08 h)	50.1° 09:20	10.9	8%	13.8°
2039-11-14 Mon	9	—	unknown	05:30–05:35 (good, 0.08 h)	50.1° 09:15	10.93	3%	28.2°
2039-11-15 Tue	11	—	unknown	05:25–05:35 (good, 0.17 h)	50.1° 09:10	10.95	0%	43.0°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-10-17&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.