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: 09-23 (100), 09-24 (100), 09-25 (100), 09-26 (100), 09-27 (100) — by astronomy; check the weather when the night is within four days.

2030-09-20astronomy score per night — click a bar for that night2030-10-19

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2030-09-20 Fri	83	—	unknown	00:05–05:35 (good, 5.5 h)	72.5° 05:10	8.63	40%	40.7°
2030-09-21 Sat	90	—	unknown	00:00–05:35 (good, 5.58 h)	72.5° 05:05	8.69	30%	52.8°
2030-09-22 Sun	98	—	unknown	23:55–05:40 (good, 5.75 h)	72.5° 05:00	8.74	22%	65.2°
2030-09-23 Mon	100	—	unknown	23:50–05:40 (good, 5.83 h)	72.5° 04:55	8.79	14%	77.8°
2030-09-24 Tue	100	—	unknown	23:50–05:40 (good, 5.83 h)	72.5° 04:55	8.84	8%	90.8°
2030-09-25 Wed	100	—	unknown	23:45–05:40 (good, 5.92 h)	72.5° 04:50	8.89	3%	104.2°
2030-09-26 Thu	100	—	unknown	23:40–05:45 (good, 6.08 h)	72.5° 04:45	8.94	0%	117.9°
2030-09-27 Fri	100	—	unknown	23:35–05:45 (good, 6.17 h)	72.5° 04:40	8.99	0%	132.0°
2030-09-28 Sat	100	—	unknown	23:30–05:45 (good, 6.25 h)	72.5° 04:40	9.04	3%	146.2°
2030-09-29 Sun	100	—	unknown	23:30–05:45 (good, 6.25 h)	72.5° 04:35	9.08	8%	160.6°
2030-09-30 Mon	100	—	unknown	23:25–05:50 (good, 6.42 h)	72.5° 04:30	9.13	16%	174.3°
2030-10-01 Tue	100	—	unknown	23:20–05:50 (good, 6.5 h)	72.5° 04:25	9.18	25%	169.7°
2030-10-02 Wed	100	—	unknown	23:15–05:50 (good, 6.58 h)	72.5° 04:20	9.23	36%	155.7°
2030-10-03 Thu	100	—	unknown	23:15–05:50 (good, 6.58 h)	72.5° 04:20	9.28	47%	141.6°
2030-10-04 Fri	100	—	unknown	23:15–05:50 (good, 6.58 h)	72.5° 04:15	9.32	58%	127.7°
2030-10-05 Sat	100	—	unknown	23:15–05:55 (good, 6.67 h)	72.5° 04:10	9.37	69%	113.9°
2030-10-06 Sun	100	—	unknown	23:20–05:55 (good, 6.58 h)	72.5° 04:05	9.42	79%	100.4°
2030-10-07 Mon	100	—	unknown	23:45–05:55 (good, 6.17 h)	72.5° 04:00	9.46	87%	87.0°
2030-10-08 Tue	100	—	unknown	01:20–05:55 (good, 4.58 h)	72.5° 04:00	9.51	93%	73.8°
2030-10-09 Wed	70	—	unknown	04:00–06:00 (good, 2.0 h)	72.5° 03:55	9.56	97%	60.9°
2030-10-10 Thu	48	—	unknown	23:05–06:00 (marginal, 6.92 h)	72.5° 03:50	9.6	100%	48.1°
2030-10-11 Fri	29	—	unknown	02:25–06:00 (marginal, 3.58 h)	72.5° 03:45	9.65	100%	35.6°
2030-10-12 Sat	21	—	unknown	04:25–06:00 (marginal, 1.58 h)	72.5° 03:45	9.69	98%	23.3°
2030-10-13 Sun	21	—	unknown	22:50–00:35 (marginal, 1.75 h)	72.5° 03:40	9.74	94%	11.4°
2030-10-14 Mon	27	—	unknown	22:25–06:05 (marginal, 7.67 h)	72.5° 03:35	9.78	89%	3.5°
2030-10-15 Tue	38	—	unknown	22:10–06:05 (marginal, 7.92 h)	72.5° 03:30	9.82	82%	13.4°
2030-10-16 Wed	52	—	unknown	22:00–06:05 (marginal, 8.08 h)	72.5° 03:25	9.87	75%	25.0°
2030-10-17 Thu	79	—	unknown	22:15–02:20 (good, 4.08 h)	72.5° 03:25	9.91	66%	36.8°
2030-10-18 Fri	87	—	unknown	22:15–06:05 (good, 7.83 h)	72.5° 03:20	9.95	57%	48.6°
2030-10-19 Sat	95	—	unknown	22:10–06:10 (good, 8.0 h)	72.5° 03:15	9.99	47%	60.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2030-09-20&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.