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.

2047-07-19astronomy score per night — click a bar for that night2047-08-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-07-19 Fri	1	—	unknown	—	50.1° 18:05	5.17	9%	104.0°
2047-07-20 Sat	1	—	unknown	—	50.1° 18:00	5.22	4%	91.7°
2047-07-21 Sun	1	—	unknown	—	50.1° 17:55	5.27	1%	79.1°
2047-07-22 Mon	0	—	unknown	—	50.1° 17:50	5.32	0%	66.2°
2047-07-23 Tue	0	—	unknown	—	50.1° 17:50	5.37	1%	53.2°
2047-07-24 Wed	0	—	unknown	—	50.1° 17:45	5.42	5%	40.0°
2047-07-25 Thu	0	—	unknown	—	50.1° 17:40	5.47	10%	26.9°
2047-07-26 Fri	0	—	unknown	—	50.1° 17:35	5.52	18%	14.9°
2047-07-27 Sat	0	—	unknown	—	50.1° 17:30	5.57	28%	10.3°
2047-07-28 Sun	0	—	unknown	—	50.1° 17:30	5.63	39%	19.6°
2047-07-29 Mon	0	—	unknown	—	50.1° 17:25	5.68	50%	32.5°
2047-07-30 Tue	0	—	unknown	—	50.1° 17:20	5.73	62%	46.2°
2047-07-31 Wed	0	—	unknown	—	50.1° 17:15	5.79	72%	60.0°
2047-08-01 Thu	0	—	unknown	—	50.1° 17:10	5.84	82%	73.9°
2047-08-02 Fri	0	—	unknown	—	50.1° 17:10	5.9	90%	87.7°
2047-08-03 Sat	0	—	unknown	—	50.1° 17:05	5.95	96%	101.4°
2047-08-04 Sun	0	—	unknown	—	50.1° 17:00	6.01	99%	114.9°
2047-08-05 Mon	0	—	unknown	—	50.1° 16:55	6.07	100%	128.0°
2047-08-06 Tue	0	—	unknown	—	50.1° 16:50	6.12	99%	140.8°
2047-08-07 Wed	0	—	unknown	—	50.1° 16:50	6.18	95%	153.0°
2047-08-08 Thu	0	—	unknown	—	50.1° 16:45	6.24	90%	164.0°
2047-08-09 Fri	0	—	unknown	—	50.1° 16:40	6.29	83%	170.1°
2047-08-10 Sat	0	—	unknown	—	50.1° 16:35	6.35	75%	164.7°
2047-08-11 Sun	0	—	unknown	—	50.1° 16:35	6.41	67%	154.4°
2047-08-12 Mon	0	—	unknown	—	50.1° 16:30	6.47	57%	143.2°
2047-08-13 Tue	0	—	unknown	—	50.1° 16:25	6.52	48%	131.8°
2047-08-14 Wed	0	—	unknown	—	50.1° 16:20	6.58	39%	120.1°
2047-08-15 Thu	0	—	unknown	—	50.1° 16:15	6.64	30%	108.3°
2047-08-16 Fri	0	—	unknown	—	50.1° 16:15	6.7	21%	96.1°
2047-08-17 Sat	0	—	unknown	—	50.1° 16:10	6.75	13%	83.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-07-19&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.