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: 07-12 (2), 07-13 (2), 07-14 (2), 07-15 (1), 07-16 (1) — by astronomy; check the weather when the night is within four days.

2045-07-12astronomy score per night — click a bar for that night2045-08-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2045-07-12 Wed	2	—	unknown	22:15–22:20 (marginal, 0.08 h)	50.1° 18:30	4.89	3%	95.5°
2045-07-13 Thu	2	—	unknown	—	50.1° 18:25	4.93	0%	80.8°
2045-07-14 Fri	2	—	unknown	22:10–22:15 (marginal, 0.08 h)	50.1° 18:20	4.97	0%	65.9°
2045-07-15 Sat	1	—	unknown	—	50.1° 18:15	5.02	3%	50.9°
2045-07-16 Sun	1	—	unknown	—	50.1° 18:15	5.06	9%	36.3°
2045-07-17 Mon	1	—	unknown	—	50.1° 18:10	5.1	17%	22.2°
2045-07-18 Tue	1	—	unknown	—	50.1° 18:05	5.15	27%	10.4°
2045-07-19 Wed	1	—	unknown	—	50.1° 18:00	5.2	38%	11.4°
2045-07-20 Thu	0	—	unknown	—	50.1° 17:55	5.24	48%	23.0°
2045-07-21 Fri	0	—	unknown	—	50.1° 17:55	5.29	59%	35.6°
2045-07-22 Sat	0	—	unknown	—	50.1° 17:50	5.34	69%	48.2°
2045-07-23 Sun	0	—	unknown	—	50.1° 17:45	5.39	78%	60.6°
2045-07-24 Mon	0	—	unknown	—	50.1° 17:40	5.44	86%	72.9°
2045-07-25 Tue	0	—	unknown	—	50.1° 17:40	5.49	92%	85.0°
2045-07-26 Wed	0	—	unknown	—	50.1° 17:35	5.55	96%	96.9°
2045-07-27 Thu	0	—	unknown	—	50.1° 17:30	5.6	99%	108.8°
2045-07-28 Fri	0	—	unknown	—	50.1° 17:25	5.65	100%	120.5°
2045-07-29 Sat	0	—	unknown	—	50.1° 17:20	5.71	99%	132.2°
2045-07-30 Sun	0	—	unknown	—	50.1° 17:20	5.76	96%	143.7°
2045-07-31 Mon	0	—	unknown	—	50.1° 17:15	5.81	92%	155.1°
2045-08-01 Tue	0	—	unknown	—	50.1° 17:10	5.87	86%	165.7°
2045-08-02 Wed	0	—	unknown	—	50.1° 17:05	5.93	79%	171.6°
2045-08-03 Thu	0	—	unknown	—	50.1° 17:00	5.98	70%	164.9°
2045-08-04 Fri	0	—	unknown	—	50.1° 17:00	6.04	61%	153.7°
2045-08-05 Sat	0	—	unknown	—	50.1° 16:55	6.09	51%	141.5°
2045-08-06 Sun	0	—	unknown	—	50.1° 16:50	6.15	40%	128.6°
2045-08-07 Mon	0	—	unknown	—	50.1° 16:45	6.21	30%	115.3°
2045-08-08 Tue	0	—	unknown	—	50.1° 16:45	6.26	20%	101.5°
2045-08-09 Wed	0	—	unknown	—	50.1° 16:40	6.32	11%	87.2°
2045-08-10 Thu	0	—	unknown	—	50.1° 16:35	6.38	5%	72.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2045-07-12&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.