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: 09-11 (100), 09-12 (100), 09-13 (100), 09-14 (100), 09-15 (100) — by astronomy; check the weather when the night is within four days.

2029-09-11astronomy score per night — click a bar for that night2029-10-10

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-09-11 Tue	100	—	unknown	00:40–05:25 (good, 4.75 h)	72.5° 05:45	8.17	17%	158.2°
2029-09-12 Wed	100	—	unknown	00:35–05:25 (good, 4.83 h)	72.5° 05:40	8.23	27%	172.7°
2029-09-13 Thu	100	—	unknown	00:30–05:30 (good, 5.0 h)	72.5° 05:35	8.28	37%	172.7°
2029-09-14 Fri	100	—	unknown	00:25–05:30 (good, 5.08 h)	72.5° 05:30	8.33	48%	158.8°
2029-09-15 Sat	100	—	unknown	00:25–05:30 (good, 5.08 h)	72.5° 05:30	8.39	60%	145.2°
2029-09-16 Sun	100	—	unknown	00:25–05:30 (good, 5.08 h)	72.5° 05:25	8.44	70%	131.9°
2029-09-17 Mon	100	—	unknown	00:20–05:35 (good, 5.25 h)	72.5° 05:20	8.49	79%	118.9°
2029-09-18 Tue	100	—	unknown	00:25–05:35 (good, 5.17 h)	72.5° 05:15	8.54	86%	106.1°
2029-09-19 Wed	100	—	unknown	00:35–05:35 (good, 5.0 h)	72.5° 05:10	8.59	93%	93.5°
2029-09-20 Thu	78	—	unknown	01:55–05:35 (good, 3.67 h)	72.5° 05:10	8.65	97%	81.1°
2029-09-21 Fri	60	—	unknown	03:40–05:40 (good, 2.0 h)	72.5° 05:05	8.7	99%	68.8°
2029-09-22 Sat	42	—	unknown	00:00–05:40 (marginal, 5.67 h)	72.5° 05:00	8.75	100%	56.7°
2029-09-23 Sun	28	—	unknown	00:10–05:40 (marginal, 5.5 h)	72.5° 04:55	8.8	98%	44.7°
2029-09-24 Mon	18	—	unknown	03:05–05:40 (marginal, 2.58 h)	72.5° 04:55	8.85	95%	32.9°
2029-09-25 Tue	18	—	unknown	00:05–05:40 (marginal, 5.58 h)	72.5° 04:50	8.9	91%	21.1°
2029-09-26 Wed	23	—	unknown	23:40–05:45 (marginal, 6.08 h)	72.5° 04:45	8.95	84%	9.3°
2029-09-27 Thu	32	—	unknown	23:25–05:45 (marginal, 6.33 h)	72.5° 04:40	9.0	77%	3.1°
2029-09-28 Fri	45	—	unknown	23:10–05:45 (marginal, 6.58 h)	72.5° 04:35	9.05	69%	14.7°
2029-09-29 Sat	62	—	unknown	00:50–03:10 (good, 2.33 h)	72.5° 04:35	9.1	59%	26.8°
2029-09-30 Sun	81	—	unknown	23:25–05:50 (good, 6.42 h)	72.5° 04:30	9.14	50%	39.1°
2029-10-01 Mon	89	—	unknown	23:20–05:50 (good, 6.5 h)	72.5° 04:25	9.19	39%	51.8°
2029-10-02 Tue	97	—	unknown	23:15–05:50 (good, 6.58 h)	72.5° 04:20	9.24	29%	64.9°
2029-10-03 Wed	100	—	unknown	23:10–05:50 (good, 6.67 h)	72.5° 04:15	9.29	20%	78.5°
2029-10-04 Thu	100	—	unknown	23:05–05:50 (good, 6.75 h)	72.5° 04:15	9.34	12%	92.5°
2029-10-05 Fri	100	—	unknown	23:05–05:55 (good, 6.83 h)	72.5° 04:10	9.38	5%	107.0°
2029-10-06 Sat	100	—	unknown	23:00–05:55 (good, 6.92 h)	72.5° 04:05	9.43	1%	121.9°
2029-10-07 Sun	100	—	unknown	22:55–05:55 (good, 7.0 h)	72.5° 04:00	9.48	0%	137.0°
2029-10-08 Mon	100	—	unknown	22:50–05:55 (good, 7.08 h)	72.5° 03:55	9.52	2%	152.2°
2029-10-09 Tue	100	—	unknown	22:50–06:00 (good, 7.17 h)	72.5° 03:55	9.57	7%	167.3°
2029-10-10 Wed	100	—	unknown	22:45–06:00 (good, 7.25 h)	72.5° 03:50	9.61	14%	177.2°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-09-11&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.