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 Seven Sisters: 09-28 (100), 09-29 (100), 09-30 (100), 10-01 (100), 10-02 (100) — by astronomy; check the weather when the night is within four days.

2043-09-18astronomy score per night — click a bar for that night2043-10-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-09-18 Fri	51	—	unknown	04:25–05:35 (good, 1.17 h)	72.6° 05:20	8.52	100%	65.9°
2043-09-19 Sat	33	—	unknown	00:15–05:35 (marginal, 5.33 h)	72.6° 05:15	8.57	99%	51.6°
2043-09-20 Sun	21	—	unknown	00:30–05:35 (marginal, 5.08 h)	72.6° 05:10	8.63	95%	37.2°
2043-09-21 Mon	17	—	unknown	00:20–05:35 (marginal, 5.25 h)	72.6° 05:05	8.68	89%	22.6°
2043-09-22 Tue	24	—	unknown	23:55–05:40 (marginal, 5.75 h)	72.5° 05:05	8.73	81%	8.1°
2043-09-23 Wed	36	—	unknown	23:35–05:40 (marginal, 6.08 h)	72.6° 05:00	8.78	71%	6.4°
2043-09-24 Thu	54	—	unknown	23:25–05:40 (marginal, 6.25 h)	72.6° 04:55	8.83	60%	20.7°
2043-09-25 Fri	71	—	unknown	00:05–05:40 (good, 5.58 h)	72.6° 04:50	8.88	48%	34.8°
2043-09-26 Sat	84	—	unknown	23:40–05:45 (good, 6.08 h)	72.5° 04:45	8.93	37%	48.7°
2043-09-27 Sun	93	—	unknown	23:35–05:45 (good, 6.17 h)	72.5° 04:45	8.98	27%	62.3°
2043-09-28 Mon	100	—	unknown	23:35–05:45 (good, 6.17 h)	72.6° 04:40	9.03	18%	75.8°
2043-09-29 Tue	100	—	unknown	23:30–05:45 (good, 6.25 h)	72.6° 04:35	9.08	10%	89.0°
2043-09-30 Wed	100	—	unknown	23:25–05:45 (good, 6.33 h)	72.6° 04:30	9.13	5%	102.0°
2043-10-01 Thu	100	—	unknown	23:20–05:50 (good, 6.5 h)	72.5° 04:25	9.17	2%	114.8°
2043-10-02 Fri	100	—	unknown	23:20–05:50 (good, 6.5 h)	72.6° 04:25	9.22	0%	127.4°
2043-10-03 Sat	100	—	unknown	23:15–05:50 (good, 6.58 h)	72.6° 04:20	9.27	1%	139.8°
2043-10-04 Sun	100	—	unknown	23:10–05:50 (good, 6.67 h)	72.6° 04:15	9.32	3%	152.0°
2043-10-05 Mon	100	—	unknown	23:05–05:55 (good, 6.83 h)	72.6° 04:10	9.36	7%	164.0°
2043-10-06 Tue	100	—	unknown	23:00–05:55 (good, 6.92 h)	72.5° 04:10	9.41	13%	175.9°
2043-10-07 Wed	100	—	unknown	23:00–05:55 (good, 6.92 h)	72.6° 04:05	9.46	20%	172.2°
2043-10-08 Thu	100	—	unknown	22:55–05:55 (good, 7.0 h)	72.6° 04:00	9.5	28%	160.4°
2043-10-09 Fri	100	—	unknown	22:50–05:55 (good, 7.08 h)	72.6° 03:55	9.55	37%	148.5°
2043-10-10 Sat	100	—	unknown	22:50–06:00 (good, 7.17 h)	72.5° 03:50	9.59	46%	136.6°
2043-10-11 Sun	100	—	unknown	22:45–06:00 (good, 7.25 h)	72.5° 03:50	9.64	56%	124.4°
2043-10-12 Mon	100	—	unknown	22:45–06:00 (good, 7.25 h)	72.6° 03:45	9.68	66%	111.9°
2043-10-13 Tue	100	—	unknown	22:50–06:00 (good, 7.17 h)	72.6° 03:40	9.73	75%	99.1°
2043-10-14 Wed	100	—	unknown	23:10–06:05 (good, 6.92 h)	72.6° 03:35	9.77	84%	85.8°
2043-10-15 Thu	100	—	unknown	00:45–06:05 (good, 5.33 h)	72.5° 03:30	9.82	91%	72.0°
2043-10-16 Fri	96	—	unknown	03:55–06:05 (good, 2.17 h)	72.6° 03:30	9.86	96%	57.9°
2043-10-17 Sat	46	—	unknown	22:40–06:05 (marginal, 7.42 h)	72.6° 03:25	9.9	100%	43.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-09-18&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.