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: 09-21 (100), 09-22 (100), 09-23 (100), 09-24 (100), 09-25 (100) — by astronomy; check the weather when the night is within four days.

2044-09-21astronomy score per night — click a bar for that night2044-10-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2044-09-21 Wed	100	—	unknown	00:00–05:40 (good, 5.67 h)	72.6° 05:05	8.72	0%	125.8°
2044-09-22 Thu	100	—	unknown	23:55–05:40 (good, 5.75 h)	72.6° 05:00	8.77	3%	139.4°
2044-09-23 Fri	100	—	unknown	23:50–05:40 (good, 5.83 h)	72.6° 04:55	8.82	7%	152.6°
2044-09-24 Sat	100	—	unknown	23:45–05:40 (good, 5.92 h)	72.6° 04:50	8.87	13%	165.4°
2044-09-25 Sun	100	—	unknown	23:40–05:45 (good, 6.08 h)	72.6° 04:50	8.92	21%	177.7°
2044-09-26 Mon	100	—	unknown	23:40–05:45 (good, 6.08 h)	72.6° 04:45	8.97	29%	169.7°
2044-09-27 Tue	100	—	unknown	23:35–05:45 (good, 6.17 h)	72.6° 04:40	9.02	38%	157.7°
2044-09-28 Wed	100	—	unknown	23:30–05:45 (good, 6.25 h)	72.6° 04:35	9.07	48%	145.9°
2044-09-29 Thu	100	—	unknown	23:30–05:45 (good, 6.25 h)	72.6° 04:30	9.11	57%	134.0°
2044-09-30 Fri	100	—	unknown	23:30–05:50 (good, 6.33 h)	72.6° 04:30	9.16	66%	122.2°
2044-10-01 Sat	100	—	unknown	23:30–05:50 (good, 6.33 h)	72.6° 04:25	9.21	75%	110.2°
2044-10-02 Sun	100	—	unknown	23:35–05:50 (good, 6.25 h)	72.6° 04:20	9.26	83%	98.0°
2044-10-03 Mon	100	—	unknown	00:10–05:50 (good, 5.67 h)	72.6° 04:15	9.31	90%	85.6°
2044-10-04 Tue	100	—	unknown	01:40–05:55 (good, 4.25 h)	72.5° 04:15	9.35	95%	72.9°
2044-10-05 Wed	66	—	unknown	04:25–05:55 (good, 1.5 h)	72.6° 04:10	9.4	99%	59.9°
2044-10-06 Thu	42	—	unknown	23:20–05:55 (marginal, 6.58 h)	72.6° 04:05	9.45	100%	46.6°
2044-10-07 Fri	24	—	unknown	03:30–05:55 (marginal, 2.42 h)	72.6° 04:00	9.49	99%	33.0°
2044-10-08 Sat	19	—	unknown	04:45–05:55 (marginal, 1.17 h)	72.6° 03:55	9.54	96%	19.2°
2044-10-09 Sun	22	—	unknown	22:55–03:25 (marginal, 4.5 h)	72.6° 03:55	9.58	90%	5.3°
2044-10-10 Mon	33	—	unknown	22:35–06:00 (marginal, 7.42 h)	72.6° 03:50	9.63	82%	9.0°
2044-10-11 Tue	49	—	unknown	22:20–06:00 (marginal, 7.67 h)	72.6° 03:45	9.67	72%	23.1°
2044-10-12 Wed	65	—	unknown	23:00–03:20 (good, 4.33 h)	72.6° 03:40	9.72	61%	37.3°
2044-10-13 Thu	85	—	unknown	22:30–06:05 (good, 7.58 h)	72.6° 03:35	9.76	50%	51.5°
2044-10-14 Fri	96	—	unknown	22:25–06:05 (good, 7.67 h)	72.6° 03:35	9.81	39%	65.6°
2044-10-15 Sat	100	—	unknown	22:25–06:05 (good, 7.67 h)	72.6° 03:30	9.85	28%	79.6°
2044-10-16 Sun	100	—	unknown	22:20–06:05 (good, 7.75 h)	72.6° 03:25	9.89	18%	93.6°
2044-10-17 Mon	100	—	unknown	22:15–06:05 (good, 7.83 h)	72.6° 03:20	9.93	11%	107.4°
2044-10-18 Tue	100	—	unknown	22:10–06:10 (good, 8.0 h)	72.5° 03:20	9.98	5%	121.0°
2044-10-19 Wed	100	—	unknown	22:10–06:10 (good, 8.0 h)	72.6° 03:15	10.02	1%	134.5°
2044-10-20 Thu	100	—	unknown	22:05–06:10 (good, 8.08 h)	72.6° 03:10	10.06	0%	147.7°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2044-09-21&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.