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: 11-08 (3), 11-09 (3), 11-07 (2), 11-03 (1), 11-04 (1) — by astronomy; check the weather when the night is within four days.

2041-10-11astronomy score per night — click a bar for that night2041-11-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2041-10-11 Fri	0	—	unknown	—	50.1° 12:30	9.66	94%	137.0°
2041-10-12 Sat	0	—	unknown	—	50.1° 12:25	9.71	87%	123.0°
2041-10-13 Sun	0	—	unknown	—	50.1° 12:25	9.75	78%	109.4°
2041-10-14 Mon	0	—	unknown	—	50.1° 12:20	9.79	69%	96.2°
2041-10-15 Tue	0	—	unknown	—	50.1° 12:15	9.84	60%	83.5°
2041-10-16 Wed	0	—	unknown	—	50.1° 12:10	9.88	50%	71.2°
2041-10-17 Thu	0	—	unknown	—	50.1° 12:05	9.92	40%	59.1°
2041-10-18 Fri	0	—	unknown	—	50.1° 12:00	9.97	31%	47.1°
2041-10-19 Sat	0	—	unknown	—	50.1° 11:55	10.01	22%	35.3°
2041-10-20 Sun	0	—	unknown	—	50.1° 11:50	10.05	15%	23.6°
2041-10-21 Mon	0	—	unknown	—	50.1° 11:50	10.09	9%	11.8°
2041-10-22 Tue	0	—	unknown	—	50.1° 11:45	10.13	4%	2.1°
2041-10-23 Wed	0	—	unknown	—	50.1° 11:40	10.17	1%	12.6°
2041-10-24 Thu	0	—	unknown	—	50.1° 11:35	10.21	0%	24.7°
2041-10-25 Fri	0	—	unknown	—	50.1° 11:30	10.25	1%	37.1°
2041-10-26 Sat	0	—	unknown	—	50.1° 10:30	10.29	3%	49.7°
2041-10-27 Sun	0	—	unknown	—	50.1° 10:25	10.33	8%	62.5°
2041-10-28 Mon	0	—	unknown	—	50.1° 10:20	10.37	15%	75.5°
2041-10-29 Tue	0	—	unknown	—	50.1° 10:15	10.4	23%	88.7°
2041-10-30 Wed	0	—	unknown	—	50.1° 10:10	10.44	33%	102.1°
2041-10-31 Thu	0	—	unknown	—	50.1° 10:10	10.48	44%	115.7°
2041-11-01 Fri	0	—	unknown	—	50.1° 10:05	10.51	55%	129.6°
2041-11-02 Sat	0	—	unknown	—	50.1° 10:00	10.55	66%	143.8°
2041-11-03 Sun	1	—	unknown	—	50.1° 09:55	10.59	76%	158.1°
2041-11-04 Mon	1	—	unknown	—	50.1° 09:55	10.62	86%	172.5°
2041-11-05 Tue	1	—	unknown	—	50.1° 09:50	10.66	93%	172.3°
2041-11-06 Wed	1	—	unknown	—	50.1° 09:45	10.69	98%	157.9°
2041-11-07 Thu	2	—	unknown	05:25–05:30 (marginal, 0.08 h)	50.1° 09:40	10.72	100%	143.4°
2041-11-08 Fri	3	—	unknown	05:20–05:30 (marginal, 0.17 h)	50.1° 09:35	10.76	99%	129.1°
2041-11-09 Sat	3	—	unknown	05:20–05:30 (marginal, 0.17 h)	50.1° 09:35	10.79	96%	115.1°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2041-10-11&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.