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: 07-19 (1), 07-20 (1), 07-21 (1) — by astronomy; check the weather when the night is within four days.

2039-07-19astronomy score per night — click a bar for that night2039-08-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-07-19 Tue	1	—	unknown	—	50.1° 18:05	5.17	2%	84.3°
2039-07-20 Wed	1	—	unknown	—	50.1° 18:00	5.22	0%	72.1°
2039-07-21 Thu	1	—	unknown	—	50.1° 17:55	5.27	0%	59.8°
2039-07-22 Fri	0	—	unknown	—	50.1° 17:50	5.31	3%	47.3°
2039-07-23 Sat	0	—	unknown	—	50.1° 17:45	5.36	7%	34.6°
2039-07-24 Sun	0	—	unknown	—	50.1° 17:45	5.41	13%	21.7°
2039-07-25 Mon	0	—	unknown	—	50.1° 17:40	5.47	21%	8.5°
2039-07-26 Tue	0	—	unknown	—	50.1° 17:35	5.52	30%	4.8°
2039-07-27 Wed	0	—	unknown	—	50.1° 17:30	5.57	41%	18.4°
2039-07-28 Thu	0	—	unknown	—	50.1° 17:30	5.62	52%	32.3°
2039-07-29 Fri	0	—	unknown	—	50.1° 17:25	5.68	64%	46.4°
2039-07-30 Sat	0	—	unknown	—	50.1° 17:20	5.73	74%	60.8°
2039-07-31 Sun	0	—	unknown	—	50.1° 17:15	5.78	84%	75.3°
2039-08-01 Mon	0	—	unknown	—	50.1° 17:10	5.84	92%	90.0°
2039-08-02 Tue	0	—	unknown	—	50.1° 17:10	5.89	97%	104.7°
2039-08-03 Wed	0	—	unknown	—	50.1° 17:05	5.95	100%	119.3°
2039-08-04 Thu	0	—	unknown	—	50.1° 17:00	6.01	100%	133.7°
2039-08-05 Fri	0	—	unknown	—	50.1° 16:55	6.06	97%	147.7°
2039-08-06 Sat	0	—	unknown	—	50.1° 16:50	6.12	92%	161.5°
2039-08-07 Sun	0	—	unknown	—	50.1° 16:50	6.18	85%	174.8°
2039-08-08 Mon	0	—	unknown	—	50.1° 16:45	6.23	77%	172.3°
2039-08-09 Tue	0	—	unknown	—	50.1° 16:40	6.29	68%	159.8°
2039-08-10 Wed	0	—	unknown	—	50.1° 16:35	6.35	58%	147.5°
2039-08-11 Thu	0	—	unknown	—	50.1° 16:35	6.4	49%	135.5°
2039-08-12 Fri	0	—	unknown	—	50.1° 16:30	6.46	40%	123.6°
2039-08-13 Sat	0	—	unknown	—	50.1° 16:25	6.52	30%	111.8°
2039-08-14 Sun	0	—	unknown	—	50.1° 16:20	6.58	22%	99.9°
2039-08-15 Mon	0	—	unknown	—	50.1° 16:15	6.63	15%	87.9°
2039-08-16 Tue	0	—	unknown	—	50.1° 16:15	6.69	9%	75.8°
2039-08-17 Wed	0	—	unknown	—	50.1° 16:10	6.75	4%	63.5°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-07-19&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.