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: 11-09 (4), 11-08 (3), 11-07 (2), 11-04 (1), 11-05 (1) — by astronomy; check the weather when the night is within four days.

2045-10-11astronomy score per night — click a bar for that night2045-11-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-10-11 Wed	0	—	unknown	—	50.1° 12:30	9.66	3%	34.3°
2045-10-12 Thu	0	—	unknown	—	50.1° 12:25	9.71	8%	47.8°
2045-10-13 Fri	0	—	unknown	—	50.1° 12:25	9.75	15%	61.1°
2045-10-14 Sat	0	—	unknown	—	50.1° 12:20	9.79	23%	73.9°
2045-10-15 Sun	0	—	unknown	—	50.1° 12:15	9.84	32%	86.5°
2045-10-16 Mon	0	—	unknown	—	50.1° 12:10	9.88	42%	98.7°
2045-10-17 Tue	0	—	unknown	—	50.1° 12:05	9.92	51%	110.6°
2045-10-18 Wed	0	—	unknown	—	50.1° 12:00	9.97	61%	122.4°
2045-10-19 Thu	0	—	unknown	—	50.1° 12:00	10.01	70%	134.0°
2045-10-20 Fri	0	—	unknown	—	50.1° 11:50	10.05	78%	145.5°
2045-10-21 Sat	0	—	unknown	—	50.1° 11:50	10.09	85%	156.9°
2045-10-22 Sun	0	—	unknown	—	50.1° 11:45	10.13	91%	167.3°
2045-10-23 Mon	0	—	unknown	—	50.1° 11:40	10.17	96%	171.2°
2045-10-24 Tue	0	—	unknown	—	50.1° 11:35	10.21	99%	162.8°
2045-10-25 Wed	0	—	unknown	—	50.1° 11:30	10.25	100%	151.1°
2045-10-26 Thu	0	—	unknown	—	50.1° 11:30	10.29	99%	138.6°
2045-10-27 Fri	0	—	unknown	—	50.1° 11:25	10.33	95%	125.8°
2045-10-28 Sat	0	—	unknown	—	50.1° 10:20	10.37	90%	112.6°
2045-10-29 Sun	0	—	unknown	—	50.1° 10:15	10.41	82%	99.3°
2045-10-30 Mon	0	—	unknown	—	50.1° 10:10	10.44	73%	85.7°
2045-10-31 Tue	0	—	unknown	—	50.1° 10:10	10.48	63%	72.0°
2045-11-01 Wed	0	—	unknown	—	50.1° 10:05	10.52	52%	58.2°
2045-11-02 Thu	0	—	unknown	—	50.1° 10:00	10.55	41%	44.4°
2045-11-03 Fri	0	—	unknown	—	50.1° 09:55	10.59	30%	30.6°
2045-11-04 Sat	1	—	unknown	—	50.1° 09:55	10.62	20%	17.3°
2045-11-05 Sun	1	—	unknown	—	50.1° 09:50	10.66	11%	8.5°
2045-11-06 Mon	1	—	unknown	—	50.1° 09:45	10.69	5%	15.8°
2045-11-07 Tue	2	—	unknown	05:25–05:30 (marginal, 0.08 h)	50.1° 09:40	10.72	1%	28.8°
2045-11-08 Wed	3	—	unknown	05:50–06:05 (marginal, 0.25 h)	50.1° 09:35	10.76	0%	42.2°
2045-11-09 Thu	4	—	unknown	05:45–06:05 (marginal, 0.33 h)	50.1° 09:35	10.79	1%	55.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-10-11&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.