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: 09-16 (100), 08-29 (96), 08-30 (96), 08-31 (96), 09-15 (96) — by astronomy; check the weather when the night is within four days.

2047-08-18astronomy score per night — click a bar for that night2047-09-16

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2047-08-18 Sun	66	—	unknown	02:15–04:50 (good, 2.58 h)	72.6° 07:20	6.81	7%	55.5°
2047-08-19 Mon	71	—	unknown	02:10–04:55 (good, 2.75 h)	72.6° 07:15	6.87	3%	68.8°
2047-08-20 Tue	74	—	unknown	02:05–04:55 (good, 2.83 h)	72.6° 07:15	6.93	0%	82.5°
2047-08-21 Wed	76	—	unknown	02:05–04:55 (good, 2.83 h)	72.6° 07:10	6.98	0%	96.5°
2047-08-22 Thu	80	—	unknown	02:00–05:00 (good, 3.0 h)	72.6° 07:05	7.04	3%	110.7°
2047-08-23 Fri	82	—	unknown	01:55–05:00 (good, 3.08 h)	72.6° 07:00	7.1	9%	125.0°
2047-08-24 Sat	84	—	unknown	01:50–05:00 (good, 3.17 h)	72.6° 06:55	7.15	16%	139.5°
2047-08-25 Sun	86	—	unknown	01:45–05:00 (good, 3.25 h)	72.6° 06:55	7.21	26%	153.9°
2047-08-26 Mon	89	—	unknown	01:45–05:05 (good, 3.33 h)	72.6° 06:50	7.27	36%	168.2°
2047-08-27 Tue	91	—	unknown	01:40–05:05 (good, 3.42 h)	72.6° 06:45	7.33	48%	177.5°
2047-08-28 Wed	93	—	unknown	01:35–05:05 (good, 3.5 h)	72.6° 06:40	7.38	59%	163.5°
2047-08-29 Thu	96	—	unknown	01:30–05:10 (good, 3.67 h)	72.6° 06:35	7.44	70%	149.7°
2047-08-30 Fri	96	—	unknown	01:35–05:10 (good, 3.58 h)	72.6° 06:35	7.49	80%	136.0°
2047-08-31 Sat	96	—	unknown	01:30–05:10 (good, 3.67 h)	72.6° 06:30	7.55	88%	122.5°
2047-09-01 Sun	91	—	unknown	01:35–05:10 (good, 3.58 h)	72.6° 06:25	7.61	94%	109.2°
2047-09-02 Mon	68	—	unknown	01:40–05:15 (good, 3.58 h)	72.6° 06:20	7.66	98%	96.2°
2047-09-03 Tue	53	—	unknown	02:55–05:15 (good, 2.33 h)	72.6° 06:20	7.72	100%	83.3°
2047-09-04 Wed	40	—	unknown	04:20–05:15 (good, 0.92 h)	72.6° 06:15	7.77	100%	70.7°
2047-09-05 Thu	29	—	unknown	01:05–05:15 (marginal, 4.17 h)	72.6° 06:10	7.83	97%	58.3°
2047-09-06 Fri	21	—	unknown	01:10–05:20 (marginal, 4.17 h)	72.6° 06:05	7.88	93%	46.1°
2047-09-07 Sat	16	—	unknown	01:15–05:20 (marginal, 4.08 h)	72.6° 06:00	7.94	88%	34.0°
2047-09-08 Sun	18	—	unknown	00:55–05:20 (marginal, 4.42 h)	72.6° 06:00	7.99	81%	22.1°
2047-09-09 Mon	25	—	unknown	00:40–05:20 (marginal, 4.67 h)	72.6° 05:55	8.05	73%	10.3°
2047-09-10 Tue	35	—	unknown	00:25–05:25 (marginal, 5.0 h)	72.6° 05:50	8.1	64%	1.7°
2047-09-11 Wed	48	—	unknown	03:00–04:20 (good, 1.33 h)	72.6° 05:45	8.16	55%	13.5°
2047-09-12 Thu	64	—	unknown	01:00–05:25 (good, 4.42 h)	72.6° 05:40	8.21	46%	25.5°
2047-09-13 Fri	80	—	unknown	00:30–05:30 (good, 5.0 h)	72.6° 05:40	8.26	36%	37.8°
2047-09-14 Sat	89	—	unknown	00:30–05:30 (good, 5.0 h)	72.6° 05:35	8.32	27%	50.4°
2047-09-15 Sun	96	—	unknown	00:25–05:30 (good, 5.08 h)	72.6° 05:30	8.37	18%	63.4°
2047-09-16 Mon	100	—	unknown	00:20–05:30 (good, 5.17 h)	72.6° 05:25	8.42	10%	76.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2047-08-18&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.