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: 09-01 (100), 09-02 (100), 09-03 (100), 09-04 (100), 09-05 (100) — by astronomy; check the weather when the night is within four days.

2043-08-31astronomy score per night — click a bar for that night2043-09-29

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2043-08-31 Mon	96	—	unknown	01:25–05:10 (good, 3.75 h)	72.6° 06:30	7.55	8%	65.8°
2043-09-01 Tue	100	—	unknown	01:20–05:10 (good, 3.83 h)	72.6° 06:25	7.6	3%	79.4°
2043-09-02 Wed	100	—	unknown	01:15–05:15 (good, 4.0 h)	72.6° 06:20	7.66	0%	92.8°
2043-09-03 Thu	100	—	unknown	01:10–05:15 (good, 4.08 h)	72.5° 06:15	7.72	0%	106.0°
2043-09-04 Fri	100	—	unknown	01:10–05:15 (good, 4.08 h)	72.6° 06:15	7.77	2%	118.9°
2043-09-05 Sat	100	—	unknown	01:05–05:15 (good, 4.17 h)	72.6° 06:10	7.83	6%	131.5°
2043-09-06 Sun	100	—	unknown	01:00–05:20 (good, 4.33 h)	72.6° 06:05	7.88	11%	143.8°
2043-09-07 Mon	100	—	unknown	00:55–05:20 (good, 4.42 h)	72.5° 06:00	7.94	18%	156.0°
2043-09-08 Tue	100	—	unknown	00:50–05:20 (good, 4.5 h)	72.5° 06:00	7.99	26%	167.9°
2043-09-09 Wed	100	—	unknown	00:50–05:20 (good, 4.5 h)	72.6° 05:55	8.05	35%	179.5°
2043-09-10 Thu	100	—	unknown	00:45–05:25 (good, 4.67 h)	72.6° 05:50	8.1	44%	168.4°
2043-09-11 Fri	100	—	unknown	00:40–05:25 (good, 4.75 h)	72.6° 05:45	8.15	54%	156.5°
2043-09-12 Sat	100	—	unknown	00:35–05:25 (good, 4.83 h)	72.5° 05:40	8.21	63%	144.5°
2043-09-13 Sun	100	—	unknown	00:40–05:25 (good, 4.75 h)	72.5° 05:40	8.26	72%	132.2°
2043-09-14 Mon	100	—	unknown	00:35–05:30 (good, 4.92 h)	72.6° 05:35	8.31	81%	119.7°
2043-09-15 Tue	100	—	unknown	00:40–05:30 (good, 4.83 h)	72.6° 05:30	8.37	88%	106.8°
2043-09-16 Wed	100	—	unknown	00:45–05:30 (good, 4.75 h)	72.6° 05:25	8.42	94%	93.6°
2043-09-17 Thu	72	—	unknown	02:10–05:30 (good, 3.33 h)	72.5° 05:20	8.47	98%	79.9°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2043-08-31&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.