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: 09-01 (100), 08-30 (99), 08-29 (98), 08-31 (98), 09-02 (96) — by astronomy; check the weather when the night is within four days.

2036-08-17astronomy score per night — click a bar for that night2036-09-15

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2036-08-17 Sun	55	—	unknown	02:15–04:50 (good, 2.58 h)	72.5° 07:20	6.79	20%	33.7°
2036-08-18 Mon	66	—	unknown	02:10–04:55 (good, 2.75 h)	72.5° 07:15	6.85	11%	47.8°
2036-08-19 Tue	72	—	unknown	02:05–04:55 (good, 2.83 h)	72.5° 07:15	6.91	5%	62.5°
2036-08-20 Wed	76	—	unknown	02:05–04:55 (good, 2.83 h)	72.5° 07:10	6.96	1%	77.4°
2036-08-21 Thu	78	—	unknown	02:00–04:55 (good, 2.92 h)	72.5° 07:05	7.02	0%	92.4°
2036-08-22 Fri	81	—	unknown	01:55–05:00 (good, 3.08 h)	72.5° 07:00	7.08	2%	107.3°
2036-08-23 Sat	83	—	unknown	01:50–05:00 (good, 3.17 h)	72.5° 07:00	7.13	7%	121.9°
2036-08-24 Sun	86	—	unknown	01:50–05:00 (good, 3.17 h)	72.5° 06:55	7.19	14%	136.0°
2036-08-25 Mon	89	—	unknown	01:45–05:05 (good, 3.33 h)	72.5° 06:50	7.25	23%	149.4°
2036-08-26 Tue	91	—	unknown	01:40–05:05 (good, 3.42 h)	72.5° 06:45	7.31	33%	161.7°
2036-08-27 Wed	92	—	unknown	01:35–05:05 (good, 3.5 h)	72.5° 06:40	7.36	43%	170.3°
2036-08-28 Thu	95	—	unknown	01:30–05:05 (good, 3.58 h)	72.5° 06:40	7.42	53%	166.5°
2036-08-29 Fri	98	—	unknown	01:30–05:10 (good, 3.67 h)	72.5° 06:35	7.48	63%	156.0°
2036-08-30 Sat	99	—	unknown	01:30–05:10 (good, 3.67 h)	72.5° 06:30	7.53	72%	144.6°
2036-08-31 Sun	98	—	unknown	01:25–05:10 (good, 3.75 h)	72.5° 06:25	7.59	80%	133.0°
2036-09-01 Mon	100	—	unknown	01:25–05:15 (good, 3.83 h)	72.5° 06:20	7.64	87%	121.4°
2036-09-02 Tue	96	—	unknown	01:25–05:15 (good, 3.83 h)	72.5° 06:20	7.7	93%	109.7°
2036-09-03 Wed	75	—	unknown	01:35–05:15 (good, 3.67 h)	72.5° 06:15	7.75	97%	98.0°
2036-09-04 Thu	61	—	unknown	02:20–05:15 (good, 2.92 h)	72.5° 06:10	7.81	99%	86.3°
2036-09-05 Fri	48	—	unknown	03:35–05:20 (good, 1.75 h)	72.5° 06:05	7.86	100%	74.5°
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°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2036-08-17&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.