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: 09-09 (100), 09-10 (100), 09-11 (100), 09-12 (100), 09-13 (100) — by astronomy; check the weather when the night is within four days.

2034-09-01astronomy score per night — click a bar for that night2034-09-30

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2034-09-01 Fri	19	—	unknown	01:20–05:10 (marginal, 3.83 h)	72.5° 06:25	7.61	87%	38.2°
2034-09-02 Sat	20	—	unknown	01:10–05:15 (marginal, 4.08 h)	72.5° 06:20	7.67	78%	24.5°
2034-09-03 Sun	29	—	unknown	00:55–05:15 (marginal, 4.33 h)	72.5° 06:15	7.73	68%	12.4°
2034-09-04 Mon	42	—	unknown	03:50–04:35 (good, 0.75 h)	72.5° 06:10	7.78	56%	10.5°
2034-09-05 Tue	57	—	unknown	01:25–05:15 (good, 3.83 h)	72.5° 06:10	7.84	45%	21.6°
2034-09-06 Wed	78	—	unknown	01:00–05:20 (good, 4.33 h)	72.5° 06:05	7.89	34%	34.8°
2034-09-07 Thu	90	—	unknown	00:55–05:20 (good, 4.42 h)	72.5° 06:00	7.95	24%	48.2°
2034-09-08 Fri	96	—	unknown	00:50–05:20 (good, 4.5 h)	72.5° 05:55	8.0	15%	61.6°
2034-09-09 Sat	100	—	unknown	00:45–05:25 (good, 4.67 h)	72.5° 05:55	8.05	8%	74.8°
2034-09-10 Sun	100	—	unknown	00:45–05:25 (good, 4.67 h)	72.5° 05:50	8.11	3%	87.9°
2034-09-11 Mon	100	—	unknown	00:40–05:25 (good, 4.75 h)	72.5° 05:45	8.16	1%	100.7°
2034-09-12 Tue	100	—	unknown	00:35–05:25 (good, 4.83 h)	72.5° 05:40	8.22	0%	113.4°
2034-09-13 Wed	100	—	unknown	00:30–05:30 (good, 5.0 h)	72.5° 05:35	8.27	2%	125.7°
2034-09-14 Thu	100	—	unknown	00:25–05:30 (good, 5.08 h)	72.5° 05:35	8.32	5%	137.8°
2034-09-15 Fri	100	—	unknown	00:25–05:30 (good, 5.08 h)	72.5° 05:30	8.38	10%	149.5°
2034-09-16 Sat	100	—	unknown	00:20–05:30 (good, 5.17 h)	72.5° 05:25	8.43	17%	160.6°
2034-09-17 Sun	100	—	unknown	00:15–05:35 (good, 5.33 h)	72.5° 05:20	8.48	24%	169.5°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2034-09-01&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.