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: 09-05 (100), 09-06 (100), 09-07 (100), 09-08 (100), 09-09 (100) — by astronomy; check the weather when the night is within four days.

2029-08-22astronomy score per night — click a bar for that night2029-09-20

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2029-08-22 Wed	55	—	unknown	02:20–05:00 (good, 2.67 h)	72.5° 07:00	7.06	98%	102.8°
2029-08-23 Thu	45	—	unknown	03:00–05:00 (good, 2.0 h)	72.5° 07:00	7.12	100%	90.1°
2029-08-24 Fri	36	—	unknown	04:10–05:00 (good, 0.83 h)	72.5° 06:55	7.17	99%	77.6°
2029-08-25 Sat	28	—	unknown	01:40–05:05 (marginal, 3.42 h)	72.5° 06:50	7.23	96%	65.3°
2029-08-26 Sun	21	—	unknown	01:45–05:05 (marginal, 3.33 h)	72.5° 06:45	7.29	92%	53.2°
2029-08-27 Mon	17	—	unknown	01:45–05:05 (marginal, 3.33 h)	72.5° 06:45	7.35	86%	41.2°
2029-08-28 Tue	16	—	unknown	01:40–05:05 (marginal, 3.42 h)	72.5° 06:40	7.4	79%	29.4°
2029-08-29 Wed	22	—	unknown	01:20–05:10 (marginal, 3.83 h)	72.5° 06:35	7.46	71%	17.6°
2029-08-30 Thu	30	—	unknown	01:05–05:10 (marginal, 4.08 h)	72.5° 06:30	7.51	62%	5.8°
2029-08-31 Fri	41	—	unknown	03:25–05:10 (good, 1.75 h)	72.5° 06:25	7.57	52%	6.4°
2029-09-01 Sat	54	—	unknown	01:40–05:10 (good, 3.5 h)	72.5° 06:25	7.63	43%	18.5°
2029-09-02 Sun	70	—	unknown	01:25–05:15 (good, 3.83 h)	72.5° 06:20	7.68	33%	30.9°
2029-09-03 Mon	87	—	unknown	01:10–05:15 (good, 4.08 h)	72.5° 06:15	7.74	24%	43.7°
2029-09-04 Tue	94	—	unknown	01:05–05:15 (good, 4.17 h)	72.5° 06:10	7.79	16%	56.9°
2029-09-05 Wed	100	—	unknown	01:00–05:20 (good, 4.33 h)	72.5° 06:05	7.85	8%	70.5°
2029-09-06 Thu	100	—	unknown	00:55–05:20 (good, 4.42 h)	72.5° 06:05	7.9	3%	84.5°
2029-09-07 Fri	100	—	unknown	00:55–05:20 (good, 4.42 h)	72.5° 06:00	7.96	0%	99.0°
2029-09-08 Sat	100	—	unknown	00:50–05:20 (good, 4.5 h)	72.5° 05:55	8.01	0%	113.7°
2029-09-09 Sun	100	—	unknown	00:45–05:25 (good, 4.67 h)	72.5° 05:50	8.07	3%	128.6°
2029-09-10 Mon	100	—	unknown	00:40–05:25 (good, 4.75 h)	72.5° 05:50	8.12	9%	143.4°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2029-08-22&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.