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: 07-11 (2), 07-12 (2), 07-13 (2), 07-14 (1), 07-15 (1) — by astronomy; check the weather when the night is within four days.

2044-07-11astronomy score per night — click a bar for that night2044-08-09

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-07-11 Mon	2	—	unknown	—	50.1° 18:30	4.86	97%	122.8°
2044-07-12 Tue	2	—	unknown	22:15–22:20 (marginal, 0.08 h)	50.1° 18:30	4.9	94%	134.7°
2044-07-13 Wed	2	—	unknown	—	50.1° 18:25	4.94	88%	146.7°
2044-07-14 Thu	1	—	unknown	—	50.1° 18:20	4.98	81%	158.7°
2044-07-15 Fri	1	—	unknown	—	50.1° 18:15	5.03	72%	169.8°
2044-07-16 Sat	1	—	unknown	—	50.1° 18:10	5.07	62%	171.4°
2044-07-17 Sun	1	—	unknown	—	50.1° 18:10	5.11	52%	160.4°
2044-07-18 Mon	1	—	unknown	—	50.1° 18:05	5.16	41%	147.3°
2044-07-19 Tue	1	—	unknown	—	50.1° 18:00	5.21	30%	133.6°
2044-07-20 Wed	1	—	unknown	—	50.1° 17:55	5.26	20%	119.4°
2044-07-21 Thu	0	—	unknown	—	50.1° 17:50	5.3	12%	104.8°
2044-07-22 Fri	0	—	unknown	—	50.1° 17:50	5.35	5%	90.0°
2044-07-23 Sat	0	—	unknown	—	50.1° 17:45	5.4	1%	75.0°
2044-07-24 Sun	0	—	unknown	—	50.1° 17:40	5.45	0%	60.0°
2044-07-25 Mon	0	—	unknown	—	50.1° 17:35	5.51	2%	45.2°
2044-07-26 Tue	0	—	unknown	—	50.1° 17:35	5.56	7%	30.9°
2044-07-27 Wed	0	—	unknown	—	50.1° 17:30	5.61	14%	17.4°
2044-07-28 Thu	0	—	unknown	—	50.1° 17:25	5.67	22%	7.3°
2044-07-29 Fri	0	—	unknown	—	50.1° 17:20	5.72	32%	13.0°
2044-07-30 Sat	0	—	unknown	—	50.1° 17:15	5.77	42%	24.8°
2044-07-31 Sun	0	—	unknown	—	50.1° 17:15	5.83	52%	36.9°
2044-08-01 Mon	0	—	unknown	—	50.1° 17:10	5.88	62%	48.9°
2044-08-02 Tue	0	—	unknown	—	50.1° 17:05	5.94	71%	60.8°
2044-08-03 Wed	0	—	unknown	—	50.1° 17:00	5.99	79%	72.6°
2044-08-04 Thu	0	—	unknown	—	50.1° 16:55	6.05	86%	84.3°
2044-08-05 Fri	0	—	unknown	—	50.1° 16:55	6.11	92%	96.0°
2044-08-06 Sat	0	—	unknown	—	50.1° 16:50	6.16	96%	107.8°
2044-08-07 Sun	0	—	unknown	—	50.1° 16:45	6.22	99%	119.7°
2044-08-08 Mon	0	—	unknown	—	50.1° 16:40	6.28	100%	131.7°
2044-08-09 Tue	0	—	unknown	—	50.1° 16:40	6.33	99%	143.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-07-11&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.