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: 09-16 (100), 09-17 (100), 09-18 (100), 09-19 (100), 09-20 (100) — by astronomy; check the weather when the night is within four days.

2036-09-06astronomy score per night — click a bar for that night2036-10-05

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-09-06 Sat	37	—	unknown	00:50–05:20 (marginal, 4.5 h)	72.5° 06:05	7.92	99%	62.5°
2036-09-07 Sun	27	—	unknown	00:55–05:20 (marginal, 4.42 h)	72.5° 06:00	7.97	96%	50.5°
2036-09-08 Mon	21	—	unknown	00:55–05:20 (marginal, 4.42 h)	72.5° 05:55	8.03	91%	38.4°
2036-09-09 Tue	20	—	unknown	00:45–05:25 (marginal, 4.67 h)	72.5° 05:50	8.08	84%	26.4°
2036-09-10 Wed	26	—	unknown	00:30–05:25 (marginal, 4.92 h)	72.5° 05:45	8.14	76%	15.1°
2036-09-11 Thu	37	—	unknown	00:15–05:25 (marginal, 5.17 h)	72.5° 05:45	8.19	66%	9.2°
2036-09-12 Fri	52	—	unknown	01:55–04:45 (good, 2.83 h)	72.5° 05:40	8.24	56%	17.0°
2036-09-13 Sat	70	—	unknown	00:50–05:30 (good, 4.67 h)	72.5° 05:35	8.3	44%	29.3°
2036-09-14 Sun	84	—	unknown	00:25–05:30 (good, 5.08 h)	72.5° 05:30	8.35	34%	42.8°
2036-09-15 Mon	92	—	unknown	00:20–05:30 (good, 5.17 h)	72.5° 05:25	8.4	23%	56.8°
2036-09-16 Tue	100	—	unknown	00:15–05:30 (good, 5.25 h)	72.5° 05:25	8.45	14%	71.2°
2036-09-17 Wed	100	—	unknown	00:15–05:35 (good, 5.33 h)	72.5° 05:20	8.51	7%	85.9°
2036-09-18 Thu	100	—	unknown	00:10–05:35 (good, 5.42 h)	72.5° 05:15	8.56	2%	100.6°
2036-09-19 Fri	100	—	unknown	00:05–05:35 (good, 5.5 h)	72.5° 05:10	8.61	0%	115.3°
2036-09-20 Sat	100	—	unknown	00:00–05:35 (good, 5.58 h)	72.5° 05:05	8.66	1%	129.8°
2036-09-21 Sun	100	—	unknown	00:00–05:40 (good, 5.67 h)	72.5° 05:05	8.71	5%	143.8°
2036-09-22 Mon	100	—	unknown	23:55–05:40 (good, 5.75 h)	72.5° 05:00	8.76	11%	157.0°
2036-09-23 Tue	100	—	unknown	23:50–05:40 (good, 5.83 h)	72.5° 04:55	8.81	19%	168.2°
2036-09-24 Wed	100	—	unknown	23:45–05:40 (good, 5.92 h)	72.5° 04:50	8.86	27%	169.4°
2036-09-25 Thu	100	—	unknown	23:40–05:45 (good, 6.08 h)	72.5° 04:50	8.91	37%	159.7°
2036-09-26 Fri	100	—	unknown	23:40–05:45 (good, 6.08 h)	72.5° 04:45	8.96	47%	148.2°
2036-09-27 Sat	100	—	unknown	23:40–05:45 (good, 6.08 h)	72.5° 04:40	9.01	56%	136.5°
2036-09-28 Sun	100	—	unknown	23:35–05:45 (good, 6.17 h)	72.5° 04:35	9.06	66%	124.8°
2036-09-29 Mon	100	—	unknown	23:35–05:45 (good, 6.17 h)	72.5° 04:30	9.11	74%	113.1°
2036-09-30 Tue	100	—	unknown	23:40–05:50 (good, 6.17 h)	72.5° 04:30	9.16	82%	101.5°
2036-10-01 Wed	100	—	unknown	23:50–05:50 (good, 6.0 h)	72.5° 04:25	9.21	89%	89.7°
2036-10-02 Thu	100	—	unknown	01:05–05:50 (good, 4.75 h)	72.5° 04:20	9.25	94%	77.9°
2036-10-03 Fri	72	—	unknown	02:55–05:50 (good, 2.92 h)	72.5° 04:15	9.3	98%	65.9°
2036-10-04 Sat	55	—	unknown	05:30–05:55 (good, 0.42 h)	72.5° 04:10	9.35	100%	53.8°
2036-10-05 Sun	36	—	unknown	23:20–05:55 (marginal, 6.58 h)	72.5° 04:10	9.4	100%	41.6°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-09-06&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.