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: 09-18 (100), 09-19 (100), 09-20 (100), 09-21 (100), 09-22 (100) — by astronomy; check the weather when the night is within four days.

2034-09-18astronomy score per night — click a bar for that night2034-10-17

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-09-18 Mon	100	—	unknown	00:10–05:35 (good, 5.42 h)	72.5° 05:15	8.53	33%	169.1°
2034-09-19 Tue	100	—	unknown	00:05–05:35 (good, 5.5 h)	72.5° 05:15	8.58	42%	159.8°
2034-09-20 Wed	100	—	unknown	00:05–05:35 (good, 5.5 h)	72.5° 05:10	8.64	51%	148.7°
2034-09-21 Thu	100	—	unknown	00:05–05:35 (good, 5.5 h)	72.5° 05:05	8.69	61%	136.9°
2034-09-22 Fri	100	—	unknown	00:00–05:40 (good, 5.67 h)	72.5° 05:00	8.74	71%	124.8°
2034-09-23 Sat	100	—	unknown	00:05–05:40 (good, 5.58 h)	72.5° 05:00	8.79	79%	112.2°
2034-09-24 Sun	100	—	unknown	00:10–05:40 (good, 5.5 h)	72.5° 04:55	8.84	87%	99.2°
2034-09-25 Mon	100	—	unknown	00:55–05:40 (good, 4.75 h)	72.5° 04:50	8.89	94%	85.8°
2034-09-26 Tue	73	—	unknown	02:30–05:45 (good, 3.25 h)	72.5° 04:45	8.94	98%	71.9°
2034-09-27 Wed	50	—	unknown	05:30–05:45 (good, 0.25 h)	72.5° 04:40	8.99	100%	57.7°
2034-09-28 Thu	31	—	unknown	23:50–05:45 (marginal, 5.92 h)	72.5° 04:40	9.04	99%	43.4°
2034-09-29 Fri	20	—	unknown	03:25–05:45 (marginal, 2.33 h)	72.5° 04:35	9.09	95%	29.1°
2034-09-30 Sat	23	—	unknown	23:25–05:50 (marginal, 6.42 h)	72.5° 04:30	9.13	89%	15.7°
2034-10-01 Sun	33	—	unknown	23:05–05:50 (marginal, 6.75 h)	72.5° 04:25	9.18	80%	9.1°
2034-10-02 Mon	48	—	unknown	22:55–05:50 (marginal, 6.92 h)	72.5° 04:20	9.23	70%	18.4°
2034-10-03 Tue	67	—	unknown	23:40–03:40 (good, 4.0 h)	72.5° 04:20	9.28	59%	31.6°
2034-10-04 Wed	86	—	unknown	23:10–05:50 (good, 6.67 h)	72.5° 04:15	9.33	48%	45.1°
2034-10-05 Thu	94	—	unknown	23:05–05:55 (good, 6.83 h)	72.5° 04:10	9.37	37%	58.4°
2034-10-06 Fri	100	—	unknown	23:00–05:55 (good, 6.92 h)	72.5° 04:05	9.42	27%	71.6°
2034-10-07 Sat	100	—	unknown	22:55–05:55 (good, 7.0 h)	72.5° 04:05	9.47	18%	84.6°
2034-10-08 Sun	100	—	unknown	22:55–05:55 (good, 7.0 h)	72.5° 04:00	9.51	11%	97.3°
2034-10-09 Mon	100	—	unknown	22:50–06:00 (good, 7.17 h)	72.5° 03:55	9.56	6%	109.8°
2034-10-10 Tue	100	—	unknown	22:45–06:00 (good, 7.25 h)	72.5° 03:50	9.6	2%	122.1°
2034-10-11 Wed	100	—	unknown	22:40–06:00 (good, 7.33 h)	72.5° 03:45	9.65	0%	134.2°
2034-10-12 Thu	100	—	unknown	22:35–06:00 (good, 7.42 h)	72.5° 03:45	9.69	0%	146.0°
2034-10-13 Fri	100	—	unknown	22:35–06:00 (good, 7.42 h)	72.5° 03:40	9.74	2%	157.3°
2034-10-14 Sat	100	—	unknown	22:30–06:05 (good, 7.58 h)	72.5° 03:35	9.78	6%	167.3°
2034-10-15 Sun	100	—	unknown	22:25–06:05 (good, 7.67 h)	72.5° 03:30	9.82	12%	170.7°
2034-10-16 Mon	100	—	unknown	22:20–06:05 (good, 7.75 h)	72.5° 03:25	9.87	18%	163.0°
2034-10-17 Tue	100	—	unknown	22:15–06:05 (good, 7.83 h)	72.5° 03:25	9.91	26%	152.3°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-09-18&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.